This is truly excellent. I have learned so much from this channel over the last few days. I've long believed that speakers are the key determinant of a rig's tone. I'm hugely grateful to be able to learn about the implications of parallel and series wiring.
I agree wiring dissimilar speakers in series is misleading for comparison purposes. That is for purposes of comparison to parallel wiring. But taking identical speakers and comparing the effect on tone in series versus parallel is a clean process. And I can tell you that series wiring enhances mid range frequencies and parallel wiring tends to scoop further. There’s also a buffering in the parallel wiring that seems to clean up the tone even further, and opposite in the series. Hence (or thence) fender amplifiers always used parallel wiring in a 2X configuration and vox amplifiers used series. They were going for different things. I love how all of these phenomena evolved together. Without a doubt the musicians decided the course of the evolution. No doubt the scientists are made right either way but the musicians are made happy. Different processes same results.
To be honest, the main reason I've always used parallel topology for connecting speakers is...twice the speakers = twice the things to go wrong (blowing a coil, dodgy spade connectors etc), and if that happens in series...buh-bye to the output transformer. In parallel, you're still presenting a load to the amp even if one speaker dies and so you've got a chance to rescue it before something expensive happens.
@@BarefacedAudio Well you also have the unfortunate OT primary to secondary short which puts the DC directly on the coil...and poof no matter which series or parallel configuration. Plenty of not well protected amps out there that don't blow fuses when they should.
Thanks a lot for this explanation, i mostly have 1x12 cabs and 8 ohm speakers and i recently got an empty 2x12 but since my speakers are 8 ohm i though about wiring them in series to get 16 ohm (more standard across amps) instead of the 4 ohm parallel (luckily i just checked and most of my amps can actually handle 4 ohm). So this is why when people who have 4x12s and have pairs of different speakers state that when they change the speaker pairs orientation X/Vertical/Horizontal without changing the wiring there are big changes in sound, the sound is changing because of the parallel/series interaction + the different sound dispersion due to the orientation.
Bizarre! Hi, Dave. Strange this should appear here NOW for me. I'm modding up an old Dallas Arbitter 50WPA to become a Hi-Watt 50W guitar set up. Decision was to build two single 12" speaker cabs. A Cellestion 8ohm Rockdriver Junior 'used' & a McKenzie C12-100Bass 1997 *NEW*... £35 each popped up ebay. Grabbed em. Straight away - I recognised the acoustic issues if in same cab (series and parallel) AND how each would act like filters on each other & in turn on themselves being substatially different magnetics and inductive storage elements. However - I'll be allowing customers to test their basses at a relatively low power & there may not be any great issues. But I will now do the maths from output transformer to the speakers as a inductor filter network. Be interesting how it sounds with my guitar... country rock stuff... my hearing being shot above 4.5/5khz...
i use two different speakers via a 2x12 cab, to achieve "MY" tone. i cant get the tone otherwise. that being said, they are the same ohm, so it works out for me.
Massive fun to be had wiring a 4x12 with pairs of different drivers as parallel/series vs series/parallel for matching/non-matching pairs- lots of options that produce results that you just can't quite recall after you break down the cab and rewire everything for all the possible combinations. Throw in an open/closed back cab option and you've got a proper hobby!
@@jublaim I have a 4x12 that came with a pair of G12M Blackbacks and a pair of G12H Greens - when I rewired it I had to decide not only how to connect them, but hwere to put them - some people swear by an X pattern, I ended up with the more sensitive Hs on the bottom, Ms on the top. Of course you then have to figire how to mic it - if the cab is just a carrier for the drivers for close micing then fair enough, but if you want to capture the sound of the cab in a room. Thank goodness for IRs!
@@AndiPicker I have a 4x12 with 2 16 Ohm G12M Greens and 2 16 Ohm 1974 G12H Creams; Creams in bottom and Greens top. Greens wired in series, Creams in series and then both pairs parallelled for 16 Ohms total, I would think that wiring like this makes the speaker pairs affect eachother less than wiring pairs in parallell and then series.
@@jublaim I think I may have wired the other way, similar speakers in parallell so they look like one 8 ohm M and one 8 ohm H version; I'm pretty sure I felt very clever when I did it, I'm pretty sure I tried it different ways, and I'm pretty sure it makes very little real difference - no one ever came up to after a gig and said that they liked the way my speakers were connected 🙃. I do know that after I finished soldering it all up with big-bore cable, I felt such a sense of relief that I wouldn't have to think about it again that I was tempted to Araldite the screws into the back of my cab so I'd never be tempted to do anyting so tiresome again.
The amps negative feedback is only taken from one impedance tap. So if the tap has no load vs a load, then the negative feedback will be different. Hence maybe some difference in tone.
That makes total sense. Thanks for the explanation. To be honest, it's never occurred to me to use two different speakers in the same circuit, perhaps because I'm a bassist.
It really depends. IMO for most amps, whereas 4 ohms sounds clearer and brighter, w more detail, 16 ohms is warmer, less lively sounding and less dynamic; e.g. I have an 18 watt combo that sounds awesome at 8 ohms through a 1x12 but like muffly garbage when you run it at 16 ohms through 2x12's (ext speaker). Conversely, classic Marshall guitar amps are so bright, aggressive and "presencey" that they usually sound better run at 16ohms through either a 2x12 or a 4x12. That config helps to smooth & even out their almost shrill tones. I also have a 50 watt Marshall 1986 bass head clone that I use as a guitar amp. Way underrated, it's hotter than a classic Fender Bassman but mellower than a Marshall 1987. Stick a boutique dist pedal in front and it'll grind like any Marshall 1987. I've tried it through a 2X12 at 16 ohm and it just doesn't sound as good as 8 or 4 ohms due to its extended lows.
The 'jagged' portions of a speaker's output plot in the higher frequencies is caused mainly by cone distortions. It is not natural guitar treble. This is true for nearly everything above 1-2kHz! Guitar speakers are a very specialist component which leads to 90% of how guitar amps sound the way they do. Great guitar tone is mainly down to 'juicy' speaker cone breakup... not the tubes as believed by many!
Brilliant explanation of what has always been a confusing subject for me...it still is, but you helped me understand some of the physics behind the electromagnetism that influences the sound we hear out of our speaker cabinets. Physics is the foundation of our electromagnetic world, my father got his PhD. in physics and electronics, a dual degree - now I understand how and why they go together. Don't get me wrong, I'm a brain damaged drooling idiot, but I'm learning how my gear works, thanks to excellent teachers like this learned gentleman. I found this channel yesterday, when I was doing a search about speaker cabinets, since I was about to buy a speaker cabinet with a speaker inside. It was a killer deal, so after I researched it a bit and went back to complete my purchase, it was sold already (sigh). But now that I know about "Barefaced Audio", and I'm intrigued by their designs, I may have to buy one of their cabinets instead. I believe in paying for tone IF it really makes a difference, because it will be with me the rest of my life (probably not much left at my old age, but my tone is important to me while I'm still here). I long ago had too many guitars and amps, sold much of them, but then I bought more again last year, so not making much progress making room in the music room. Guitars and amps gave way to pickups and speakers (and cabinets). I've got a much better idea of how speaker cabinets and speakers work together now, thanks to you professor............cheers!
honestly, I think any differences are in the output transformer. if the transformer secondaries are all would in too thin a wire, then you would have a 16 Ohm tap that sounds better than the 4 ohm tap, ( typically the case, When it is a case ) but a good output transformer will leave no audible difference. ( that's where the ampacity of the windings are properly accounted for )
We are ALL different! The speakers are too! Give each a chance to do what "He" does best(Free Will!). So give them the same signal and see Who is standing afterwards.
there`s a lot of excellent reference work on " UNCLE DOUG`s" valve amp repair and restoration channel if you hav`nt already found him, you will be kicking yourself for missing this highly knowledgable fellow ! he is the reference standard and a brilliant teacher in valve amp technology,
Hadn't though about this, very cool, great video! It may help to draw out some equivalent circuits to show a static impedance at a given frequency and show the speakers as resistors acting as voltage dividers. I think that's an easier way to get your head around it. With regards to output transformer impedance taps, yes they definitely can and do affect the sound. Especially in vintage amps where the winding process may have been less exact with more variations in response and saturation on different taps. Not to mention negative feedback in the power stage and what impedance output tap that's connected to. All interesting stuff!
Fascinating stuff Alex, I never considered the interaction between two dissimilar speakers like that. Unfortunately zilla cabs have a TH-cam channel where they have many many videos of two speakers recorded independently and mixed together to help you in imagining the sound of blending those speakers but I guess the caveat is that this would only be close of they were in parallel wiring. I've always thought go with the higher impedance setting, that way your speaker cable impedance has less of an effect on your sound (for long cable runs)
You'd need a very long skinny speakers cable for that to be a problem - not like with guitars where cable capacitance causes pretty obvious tonal changes.
Good content. I understand the explanation, but the reason I always wired my 4x12 speakers in series / parallel was reliability. If they were wired in series, a dead speaker meant a dead output transformer. That was a critical consideration as a gigging player on the road. 😬
I play bass (since 1961). I applaud your interest and your dedication, Keep on Keepin' On. (side note, we are speaking of a transfer of "feeling", right? What the player is trying to bring across, in Frequency to transfer the feeling to the listener (sympathetic resonance), what is the next step? We are speaking of selective "Vibration". A bass player is at "Home" in his envelope (very important on the stage...that's where we Live!) You Live in a "Transfer" World, what other ways can frequencies be excited in a selective way? Next step?
Thank you! That was a really good explanation, it helps me understanding what's going on. Now I'll go through impedance charts and try to make predictions...
@@Scoots1994 Being strictly scientific, that would definitely be the route to go! Although we're dealing with a certain timbre and our own taste, so I'd be happy with just a prediction that would take me in the ballpark, avoiding unnecessary trial and error, then I'd make the final judgement with my ears only.
@@Scoots1994 It's really the impedance that matters, the inductance is just want causes that change in impedance (although in truth speakers don't have simple inductance because of the moving coil and all the metal around it).
Not to mention the compression effect in a sealed box meaning dissimilar magnet strength from the stronger motor will dominate the internal air and not allow as much cone movement in the weaker motor speaker.This in theory will exaggerated frequency peaks and dips in the stronger speaker cause its not equally dampened in the air chamber by a similar motor strength speaker
had been thinking on this subject lately, and one could come up with some interesting dynamics with a 4 speaker cabinet doing some series/parallel wiring. ie 2 8ohm speakers in series, and 2 different 8 ohm speakers in series, wire the 2 pairs in parallel....
It's interesting this because with resistors in parallel, the voltage is the same on each one thus the lowest gets the most power and resistors in series, the current is the same through each thus the highest gets the most share of the voltage and the most power. Impedance peaks like resonance may get exaggerated with different speakers. With the same speakers, each have (almost, manufacturing tolerances aside) identical impedance curves and thus will share the voltage equally.
Yea. You are very right. When I was a child I did a test connecting two different speakers in series and in parallel. Serial connected they sound VERY weak, much weaker than a single speaker alone. I asked and I was told that it should sound as loud, if impedance was matched, but it wasn't the case. Now I see why. When there are four speakers involved we can connect them in series and in parallel at the same time,8 getting 8 ohms as total impedance, assuming they all are nominal 8 ohms.
"Serial connected they sound VERY weak", you may have connected the speakers out of phase (like + in on first speaker, - out of first speaker to - in on next speaker). Just connecting speakers i series should not result in a drastic lack of output volume.
@jublaim This was a long time ago, and I can't remember every step of my tests, but I'm pretty sure that I tested them both ways. In phase and out of phase. The dynamics of membranes made of paper connected to electromagnetic coils moving according to the soundwaves under half voltage or full voltage must be more complex than we think. My tests told me that serials connection wasn't efficient.
Right now I pair a Alnico Creamback and a Neo Creamback in an oversized open back cab and it sounds huge.The reason why I prefer series wiring is I get a 16 Ohm cab and can pair it with another 16 Ohm cab to get 8 Ohm in total - what most amps can provide..
Most traditional solid state amps, have very high levels of voltage feedback in order to stabilise them by design, hence at resonance the output gain is massively reduced producing the more mid focused sound most associate with cheaper/traditional solid state designs. Amplifiers designed with a portion of current feedback can be designed to sound much more like a valve amplifier, in that they do not track the impedance curve of the speaker in the same manner. In that respect they would have a lower damping factor, much like that of a valve amp, the speaker is not clamped down by the output impedance of the amplifier to the same degree. This more ballistic behaviour is what people perceive as the valve sound. Putting speakers in parallel was the old world way of damping them for Hifi as their different resonance, impedance and phase angle had that limiting effect that the then valve amplifiers could not achieve. On the other hand putting drivers in series decreases damping as it makes the series impedance of the amplifier look much much larger to either of the speakers hence reducing the damping. In a valve amp with an output transformer the change of impedance ratio by tap has a huge effect on the amount of voltage feedback, and thereby the gain of the power amp and damping. All bets are off in comparison, there are so many elements at work! It’s a great subject for discussion but very hard to demonstrate without a proper level playing field. Love your content, I’d very much like to try one of your cabinets one day. All the best from Wales!
I dont beleive its the case that speakers in series are less damped because they are moving in sync and hence generating a mutual back EMF. Yes if only one speaker was moving the other speaker would act as a passive serial impedence reducing damping but that doesnt happen because the speakers are moving together.
@@pncampbell sorry my battery went while I was replying. Thanks for your response that’s got the old grey matter working. Yeah that’s a great point , I would imagine though that if overall system damping was low enough and there was enough difference between the two drivers resonance and breakup modes then the back emf would not be equal. I got some really erratic variation when testing different drivers with a power amp with mixed mode feedback to raise the output impedance for a lower damping factor. I wanted to test it further at the time but the parties involved felt the returns were diminishing for the proportion of effect on the results. This was in parallel though. I may set up a test for my own ends when I get a minute.
Fascinating. I had no idea the interaction would have such an effect. So, if you had 2 of the same speakers there would be as little effect as you could get. I’ve been thinking about how transformers play a role in sound production as well. Some of this is probably cork sniffing because these things don’t exist in isolation. There’s no way to figure out optimal sound-it’s too complicated. You really need to go with your ear. Thank god I have an amazing sounding cab…I don’t need to worrying. You guys did a great job.
brilliant. the guitar (and bass ) world needs more facts like those presented in this video. in a way, the series connection is creating a very crude crossover style network.
I did a few simple measurements today with an LCR meter, and I think you maybe should have taken the capacity of the speaker into consideration also. Maybe that will cancel out the differences. I measured a Celestion and a WGS 8 ohm 12" speaker alone, in series and in parallel: Celestion: 6.95 R / 34.6 uF / 0.71 mH WGS: 6.85 R / 38.5 uF / 0.66 mH Serial: 13.89 R / 18 uF / 1.44 mH Double / half / double Parallel: 3.58 R / 72.7 uF / 0.35 mH Half / double / half. That was as expected, but I wonder what it tells us? This is not criticism. I am also very interested in this topic. And I also have time issues, but will probably do the freq. measurements soon.
At 14:50, you say "Your amp should be a voltage source", but most guitar amps are not voltage sources. Pentodes and beam tetrodes are pretty close to voltage controlled current sinks in their linear operating range. A push-pull EL34 power amp with zero negative feedback has an output impedance on the order of 100Ω (8Ω load). With negative feedback, the output impedance drops significantly, but is still pretty high. Presence and resonance controls reduce negative feedback at high and low frequencies respectively, so output impedance rises over the range they act on as you turn them up. Another way of thinking about the difference between series/parallel is to consider the current. Series-connected speakers must have identical current, but parallel-connected speakers can have different currents. Strange stuff happens with the total impedance around resonance in a series-wired circuit if the resonance frequency of the two speakers is significantly different as there will be a huge mismatch in electrical phase between the two. At high frequencies, the electrical phase will be similar unless the Le values are dramatically different (not likely in a guitar speaker), so the (scaled) total impedance isn't much different between series/parallel wiring. Regarding the output transformer question: There will be some difference in parasitics between the different taps, but I don't know how audible this might be (or if it's audible at all). Secondary winding resistance will be higher relative to the load impedance for lower impedance taps, while primary-secondary capacitive coupling will be lower. Secondary leakage inductance will be different as well.
I’ve heard blind demos of series vs parallel speaker wiring. You are correct there is a noticeable difference. Series wired speakers are definitely not my cup of tea. As for output from amps I have a Bluguitar Amp 1 it has a valve in it for the power amp but it can be run not connected to a speaker (it’s German they think of everything like guitar players doing stupid stuff) it has a 8ohm and 16ohm output if I run 16ohm into an 8ohm cab it sounds quieter and if I run 8ohm out into 8ohm cab it sounds louder also it similar in tone to using the high low guitar input sockets you get on some amp’s. That’s all I know. Interesting video.
The biggest reason why guitar players think amplifiers sound different at different transformer output taps, stems from Marshall back in the day erroneously wiring the negative feedback loop to the secondary side of the output transformer. So as you chose different load taps depending on your speaker cabinet impedance - you were inadvertently changing the negative feedback value at the same time. The second you corrected Marshall’s wiring mistake, no audible changes occur from using the different taps.
I am sure you are not right here. When for instance you put the FB on the 8 ohms tap, you will always get the same FB, no matter which speaker tap you use. All amps makers do this till this day. The more likely reason could be that that there are more / less windings on the different transformer taps, and that the same is true for speakers. The same type speaker in 8 ohms or 16 ohms will sound different. It is obvious when you check for instance Jensens speaker datasheets.
I’m guessing here, but would the negative feed back signal/characteristic be altered depending on whether or not a speaker was connected to the same transformer tap ?
@@chrisstevens4680 I've modded an amp so I can switch NFB tap between 4, ,8 and 16 Ohm and also choose different NFB resistor values. I prefer to tap NFB from the same Ohm as the connected speaker cab; it sort of gives a richer sound. It's not a huge difference but it's there. My take is that this makes the speaker(s) interact more directly with the amps NFB circuit.
@@jublaim that was my thought exactly. Also, I haven't checked yet, but I am assuming that there will be different voltages on each tap and hence a differing amount of NFB. I was building a Marshall Plexi clone but have had to put the project on ice for the last year. I will carry on with the project later this year and do the same experiments. Which amp do you have, are you going for distortion or clean and which value of NFB resistor have you found sounds best?
@chrisstevens4680 The amp is a Marshall JVM Satriani model that's been my modding victim for nearly 10 years now. I mainly go for distorted sounds. With the 16 Ohm 4x12 I use NFB from 16 Ohm tap and 200k resistor, this gives same NFB as original 100k from 4 Ohm tap. The feedback calculation is: double the output Ohm is increasing NFB with a factor of 1.41. From 4 to 16 Ohm the factor is 2.
This makes so much sense! I can hear an output difference between my 115 and my 4x10 hartke Ak cabs. I felt like it was because of the paralell 15 and the series 10s connections. But had not the knowledge to explain it. Now i do. They both produce an very equal output spl wise but when run chained the 2 cabs sound brighter in different arwas of the freq spectrum. If you stand back 5ft its barely noticeable. But right up close there is definitely some subtle differences.. This explanation helps a ton in mmy future speaker ideas as well! Great video now if i could only save enough cash for a Barefaced 8x10!!
When they’re daisy-chained they’re almost certainly in parallel so there’s something else going on. But there’s a lot of variables when combining dissimilar cabs!
@BarefacedAudio Thank you for the response! Just a thought. Running both outputs of the amp would it make the most sense to do 2) 1x15 cabs 1st output and then the 2) 4x10 cabs on the other output? Both sides 4ohm load but not combining two differently wired cabs.. I'm close to what I want bit still missing a piece.
My main goal is a larger number cones to move more air and hopefully have higher spl with not as loud of db I know the two cannot be separated but that's the path my mind is on. Is it possible that's its just the overall differences in the mechanical parameters of the speakers that make the frequency response noticeable to the ear? Best way to say it is both cabs reach a similar output level but the 15 and 10s seem to push harder in different areas of the spectrum.. Thank you for even responding! I watched a few of your videos and it got my mind going even more. It's amazing that things can be wired to work but are not "correct".. thanks again!
That is not the same as two speakers without crossovers. Crossovers in layman's terms control which frequencies go to which drivers and divides the amount of power distributed to each driver. I have a lot of experience designing crossovers and this is a very basic way of explaining it.
Great video, as always 👌 My JVM 205C has (from factory) two different 8 ohms Celestion speakers (Vintage and Heritage, Marshall branded) connected in series, so they have 16ohms combined... Wouldn't be strange to connect them in parallel and get 4ohms?
Hmm...I had always wondered if running different speakers in series had a "chewed meat" syndrome where the 2nd speaker is getting "used" and worn out electricity from the other. I knew that wasn't the case but I love the concept of used, dog eared voltage. Your example of a voltage divider is an easy concept to grasp . Another way of looking at your explanation is that series components see identical current (by physics laws) all the time and if one speaker has a change in voltage drop with a change in frequency that affects its sound, and the other speaker reacts differently, it makes sense that they affect each other because the reaction current one makes alone is affected by the other. Well done!
What you will do is change the power draw at different frequencies and thus the frequency response. For example - the resonant frequency of each speaker could be different and the highest impedance speaker at any one time will receive the most power in series (compared to the least power in parallel) which could exaggerate the frequency response as resonance tends to be quite efficient in terms of absolute power.
I paused right at the beginning to say that I have a problem that this fits perfectly. I have a 2x12 cab that is parallel but the impedance of the speakers doesn't match my new (vintage) head. If I change to series then the impedance WILL match my head. Now I get to find out what that will mean, let's watch shall we? ... Okay, got to the end. I understand it, and now I have to go look what speakers are in my 2x12, I know they don't match but I don't know about their inductive differences. They sounded great with the Soldano in high gain sounds in parallel but my new head (JCM800) I was going to go for more rock sounds. So this is going to be interesting. I knew it made a difference to the sound but didn't know why. So 2 of the same speaker it will make no difference or little difference but dissimilar speakers it will. That's really interesting.
What you're saying is very true. However, transistor amps are mainly 'constant voltage' amplifiers and valve amps are 'constant current' (CC) amplifiers. This will make further HUGE sonic differences that you have not considered. With 'CC' amps, the output transformer's internal impedance has to also be brought into the equations. CC compensates for the speaker's varying impedance and results in a more constant output level across the audio band... it's what makes the 'valve amp sound'! In the guitar world, many modern transistor guitar amps now incorporate 'constant current' techniques which enables them to mimic a valve amplifier's sonic superiority! This is a very important topic to cover and explains why the 'old design' tranny amps sound cold and less loud/dynamic. BTW, I am an amp designer. Get in touch if you want to know more about this CC business!
@@ggmobi5817 No... CC happens exclusively on the OPTX secondary. For it to take place, CC depends on being able to monitor the speaker's changing impedance and reacting accordingly. This can ONLY be done on the secondary side. That's why all our solid-state guitar amps are equipped with 'RetroTone' which produces the same performance, tone and dynamics (loudness) as a tube amp. It's the dynamics which makes a tube guitar amp appear louder, Watt for Watt, than a solid-state amp. CC corrects this and makes solid-state amps as loud as a tube amp. All the old 1970s HH solid-state amps were CC enabled... think Wilko Johnson's tones! And boy, those amps were loud!
I do PA on an amateur level. I've learnt from helping professional sound people. Id never dream of wiring drivers in series. Then again, I'd always run with at least 25% headroom on the amps. This stops the amp sending a clipped signal to the driver, which would over heat and break up. hadn't considered the rc flitering effect on the tone of each speaker if mixed. Which is the opposite of over driving guitar amps with drivers having a bigger rms than the amp, which is what guitar rigs do? Isn't it?
Great explanation and because it is approached from a physics point of view it takes away the subjective aspect of taste and hearing. Can the difference in tone caused by different size voice coils also be applied to bass speakers?
Inductance changes the response of all speakers - but with guitar speakers you have the least wiggle room to adjust for it with different design approaches because guitar speakers are just really rather strange! (The sound of electric guitar is to quite a large degree the sound of fairly large light paper cone loudspeakers designed and built with decades old technology, with all the "imperfections" that causes)
I understood it, but I hadn't thought about it before. The most I thought about speaker wiring and impedance was mixing/matching series and parallel to get the impedance for the cabinet you were looking for. The Series example seems to show that the speaker that is worse at reproducing highs is now doing it, and the one that's good at it is not? Did I get that right? And what if you swapped the speakers, would it go back to looking more like the Parallel example? My depth of electronics knowledge didn't go into this and was a good while back. I guess I'm trying to ask is does the order of the series speakers matter?
Do the amps push voltage or do the speakers draw voltage? Sorry it's been decades since university physics. I suppose, in parallel, a pushed voltage would mean the speakers reacting the same right? If the speakers are drawing the voltage, then wouldn't they sort of split the voltage with each other in a 1/V type of way?
I can't imagine someone hooking speakers in series; the two speakers will starve each other of power where and when they need it most. I just built up a four speaker cabinet and each identical speaker is 16 ohms (in parallel, of course) so I'll end up with 4 ohms. What surprises me most is I've never heard anyone talk about this before when it is so obvious and common sense if you understand ohms law.
Yes, around resonance it's certainly a weird thing - but I guess not a lot of guitar tone is happening down there, plus rooms are weird at those frequencies and guitar speakers are very non-linear down there too, so it gets hidden.
I come from a PA background and would never ever wire in series. Then again given that less ohms equals more power, this is how a PA should be wired. Plenty of headroom, ie the rms of an amp being greater than that of the drivers. I know in the esoteric tone crucial world of guitar often the reverse is necessary. I've always assumed you guys have magic amps and super strong drivers to take all that abuse from being overdriven. Maybe some cabinet builders, when mixing drivers, play white noise through them and using a mic do a spectrsl analysis, to ensure that you get a great tone? I also know damn well that many won't. Like I say, what you guys do defies my perceived wisdom. You do things I couldn't and wouldn't dare do. I've seen smoke coming out of overdriven PA cabs and someone having to unload a fire extinguisher into one of the ports.
@@stuartchapman5171 head room isn't about amp size vs speaker size. It's about how loud amp and speaker can produce, vs how loud your gig is. Oversizing amps gives you the most clean performance out of your speakers as long as drunkards are away from the volume controls. It will give you a clean sound right up to the point the speakers blow (or ensure any bad sound is from the speakers being worked too hard). Undersized amps mean the amp is the limiting factor and is the "safe" option although a heavily clipped amp tends to funnel a higher power percentage towards the tweeter and midrange drivers (although it usually sounds terrible at this point).
@TimpBizkit it's almost a different strand of the same science. I've provided many PA for lots of styles, from free parties to big clubs to Nottinghill. I've only had 2 driver incidents. I still struggle with the concept behind speaker cabs and amps, designed to be overdriven, channel strip yes, amps, not in my world. I know a lot of guys who are heavily into backline and don't have a Scooby about PA. Hats off to you for having a grasp of both. It's too much of a learning curve for me to encompass backline tech. I'll continue watching the videos though. The guitar is probably the oldest electric instrument, it follows that tone hunting is highly honed in that world, plus I use lots of pedals in my sound design work. Maybe the penny will drop one day.
@stuartchapman5171 I'm more of a hobbyist, but PA is about clean reproduction (though in practice most speakers dedicated to getting loud will be coloured compared to a good stereo at home). You are not deliberately using the amp and speakers to impart a timbre to the sound like a guitar speaker. As far as overdrive, it compresses the average power, meaning just oversize the speaker capacity compared to the amp. In terms of power handling and blowing speakers, you have to think about how much power - peak and average and in what frequency band relative to the drivers on the speakers and what the crossover settings partition to which driver. In terms of low frequency, the practical limit is not a -3 or -10 dB but at what frequency the cone unloads and starts flapping around - if you go too low with a horn or ported box. Some designs unload near their -3 others keep the cone under control but lose output but can still be used so long as you don't excessively boost.
There is more going on regarding changing impedance,depending on the type of amp. For example a amps negative feedback (if it has one) will drastically vary depending on how it’s connected at the tap. I’ve always believed that using two different speakers in parallel smoothens out each other’s bass response through damping? Am I wrong here?
Negative feedback point is very good! And the point about different speakers in parallel has got me thinking - and yes, you could be onto something there, if by "smoothing out bass response" you're referring to reducing the efficiency down there so causing the lows to roll off sooner with lower Q. Very interesting!
Thanks for your reply! I was definitely talking about how it changed the q of each speaker yes. Would love to hear a break down from you. Great videos by the way..
Yes, but then, what if you have two 2x12 cabs (both having 16-ohm speakers wired parallel - so, 8 ohms per cab) and then join them in series, so that you in effect have a 4x12 at 16 ohms total? Answer that one, smarty pants. 😂 (kidding)
Guys dont mix them in parallel either. You get the same impedance problems and again one speaker will be more pushed at certain tones and the other at different ones. In any case impedance of the speakers must be as same as possible to the output impedance of an amp to get max effect- power on the loudspeaker(s).
@@BarefacedAudio my logic... You have an 1 ohm and a 2 ohm impedance speakers in paralel to 10 V source. 1 Ohm draws 5A and 2 ohm draw 10A. (50W on first speaker and 100 W on second one) Amp must supply 15 Amps on the output aka 150 W right?
@@ggmobi5817 Sorry, I was talking about mixing speaker models, not mixing different impedance speakers. But they're reactive loads and impedance is very much non-constant, changing hugely with frequency.
@@BarefacedAudio I just made this 1 and 2 ohms as an example... We all know that different speakers with same nominal impedance vastely variate in actual impedance, so at the same frequency it can be much different and... You get my example.
So what about when 4 16ohm speakers are wired to 16ohms with 2 different speakers, will this affect the sound of the speakers. I am thinking of combining 2 celestion cl80's and 2 neo creambacks into one 4x12 because I like the low end of the cl80 and the top end of the neo. Will I lose anything from each speaker combing them or should I keep them in separate cabs.
To preserve the individual frequency response curves as best as possible, put the 2 Celestion CL80 speakers on one series loop together, and parallel with the two neo creambacks on another series loop. I mean there might be other interactions if you have a shared airspace, but electrically this will ensure a 50:50 voltage share if you are series wiring speaker sets with identical impedance curves.
Alex, how cold is it where you do these videos? It looks like you are wearing several layers. What effect does temperature have on cabs/speakers? I would guess at extremes the response would get very slightly muddied.
We don't tend to bother with heating in there so it's approximately the average outdoor temperature plus however much heat any humans/gear has point into the room - I put a thermometer in there after you asked and it's been 13-17C (ask google if you need F). It's sunny and warm outside now but it'll take a while for that room to warm up, as it's like an insulated concrete bunker. Temperature does matter with speakers but not in the way you're thinking - another video (or many) in that!
That is very interesting, but theoretic. Why don´t you back it up with a few measurements? All it takes is a PC with a decent sound card, a USB measurement microphone and REW, a free program that can measure speaker responses. Then you could try a solid state amp and a tube amp and see if there are differences. The proof is in the pudding I think British people say 🙂.
I've got all the gear to do that - what I don't have is time (that's why there haven't been any new videos for months, too busy building cabs, etc!) That's also why most videos on this channel are done as-live, zero editing. Never enough time!
So if: a 4x12 is wired parrallel with two series circuits, and i should use 2 different speakers, the same pairs should be wired in the series circuit? (positive > split to circ1 and circ2 > circ1 containing v30's > circ2 containing gt12-75's > circ1 and circ2 joining again > to the negative)?
Jens-- if you’d like to retain the natural frequency characteristics of the speakers 🔊, wire the same speaker type in SERIES, and then wire the pairs in PARALLEL. Example: V30 + V30 in series….. G12t-75 + G12t-75 in series….. V30 pair + G12t-75 pair in parallel. Hope this helps! As always…. No rules- just conventions & practices 🤘🏽
That was indeed a strange conflation of issues. Can we call this a Barefaced lie? To add, it all depends on the evidence provided. Some conspiracies are exactly that. No need to fill in the blanks yourself.
Lol.... Well, there were, are and will always be intentional political conspiraces. But the world as it has become over the past few years - some conspiracy theories are well & truly rooted in facts anf founded research. Which all gave rise to... 'about 3 to 6 months is the difference between conspiracy theory and truth'. 😁
Sorry about that - just checked on headphones and you’re quite right! I think the stereo lead from mic to camera must have been pulled halfway out. There is (much quieter) sound on the right but that must be crosstalk from the left channel. Will make sure that doesn’t happen again, thanks for letting me know!
And now I have reached the end where you allege that the speakers will be dealing independently with the same voltage. I’m sorry but that is false. They are not independent at all. They are still interdependent. I invite you to put a microphone on each dissimilar speaker wired in parallel (I have edited this comment to change series to parallel there). And you can account for variables by moving the negative feedback loop (and its resistor) tap to different taps on the output transformer to accommodate the changing impedance as you select single speakers versus both.
At least one who knows what he is talking. Not like shreding dudes knowing shit about phisics and selling their "knowledge" which destroys your sound and equipment.
Bloody guitarists...🙄 Just plug in and play, stop faffing around looking to change the world. You'd never hear of us decent folk (bassists) yanking out drivers from our already superb cabs! Just leave it alone and go practice 😂 🤣 (yes, I did follow the logic of the physics/maths but then again why would you... ?)
The difference is that tons of the tone of electric guitar is actually the tone of the speakers. Whilst most of the tone of bass guitar comes from the bass itself. (Which begs the question, why do guitarists not spend more money on speakers than guitars?)
@@BarefacedAudio worse than that, many guitarists don't value the speaker's part in their tone at all, often putting it on the amp. Bassists are easier. I love my Orange Thuderverb 200 but I can get my sound out of most amps for bass.
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This is truly excellent. I have learned so much from this channel over the last few days. I've long believed that speakers are the key determinant of a rig's tone. I'm hugely grateful to be able to learn about the implications of parallel and series wiring.
This is a brilliant yet logical realization. I totally get it, but to be fair i am a total guitar nerd so im into it.
I agree wiring dissimilar speakers in series is misleading for comparison purposes. That is for purposes of comparison to parallel wiring. But taking identical speakers and comparing the effect on tone in series versus parallel is a clean process. And I can tell you that series wiring enhances mid range frequencies and parallel wiring tends to scoop further. There’s also a buffering in the parallel wiring that seems to clean up the tone even further, and opposite in the series. Hence (or thence) fender amplifiers always used parallel wiring in a 2X configuration and vox amplifiers used series. They were going for different things.
I love how all of these phenomena evolved together. Without a doubt the musicians decided the course of the evolution. No doubt the scientists are made right either way but the musicians are made happy. Different processes same results.
To be honest, the main reason I've always used parallel topology for connecting speakers is...twice the speakers = twice the things to go wrong (blowing a coil, dodgy spade connectors etc), and if that happens in series...buh-bye to the output transformer. In parallel, you're still presenting a load to the amp even if one speaker dies and so you've got a chance to rescue it before something expensive happens.
Absolutely. I wonder how long it takes to kill a typical valve amp if the load goes open circuit?
@@BarefacedAudio Well you also have the unfortunate OT primary to secondary short which puts the DC directly on the coil...and poof no matter which series or parallel configuration. Plenty of not well protected amps out there that don't blow fuses when they should.
Thanks a lot for this explanation, i mostly have 1x12 cabs and 8 ohm speakers and i recently got an empty 2x12 but since my speakers are 8 ohm i though about wiring them in series to get 16 ohm (more standard across amps) instead of the 4 ohm parallel (luckily i just checked and most of my amps can actually handle 4 ohm).
So this is why when people who have 4x12s and have pairs of different speakers state that when they change the speaker pairs orientation X/Vertical/Horizontal without changing the wiring there are big changes in sound, the sound is changing because of the parallel/series interaction + the different sound dispersion due to the orientation.
Boaty McBoatface should be enough evidence to not rely on the internet.
Good explanation Sir.
The Internet, as for instance TH-cam 🙂
Bizarre! Hi, Dave. Strange this should appear here NOW for me. I'm modding up an old Dallas Arbitter 50WPA to become a Hi-Watt 50W guitar set up. Decision was to build two single 12" speaker cabs. A Cellestion 8ohm Rockdriver Junior 'used' & a McKenzie C12-100Bass 1997 *NEW*... £35 each popped up ebay. Grabbed em. Straight away - I recognised the acoustic issues if in same cab (series and parallel) AND how each would act like filters on each other & in turn on themselves being substatially different magnetics and inductive storage elements. However - I'll be allowing customers to test their basses at a relatively low power & there may not be any great issues. But I will now do the maths from output transformer to the speakers as a inductor filter network. Be interesting how it sounds with my guitar... country rock stuff... my hearing being shot above 4.5/5khz...
i use two different speakers via a 2x12 cab, to achieve "MY" tone. i cant get the tone otherwise. that being said, they are the same ohm, so it works out for me.
Massive fun to be had wiring a 4x12 with pairs of different drivers as parallel/series vs series/parallel for matching/non-matching pairs- lots of options that produce results that you just can't quite recall after you break down the cab and rewire everything for all the possible combinations. Throw in an open/closed back cab option and you've got a proper hobby!
Who needs to play guitar when you can fiddle endlessly? ;-) Worked for Leo Fender!
There's folks putting 4 different drivers in a 4x12 to have more options for miking up in the studio; how they wire them I don't know🙄
@@jublaim I have a 4x12 that came with a pair of G12M Blackbacks and a pair of G12H Greens - when I rewired it I had to decide not only how to connect them, but hwere to put them - some people swear by an X pattern, I ended up with the more sensitive Hs on the bottom, Ms on the top. Of course you then have to figire how to mic it - if the cab is just a carrier for the drivers for close micing then fair enough, but if you want to capture the sound of the cab in a room. Thank goodness for IRs!
@@AndiPicker I have a 4x12 with 2 16 Ohm G12M Greens and 2 16 Ohm 1974 G12H Creams; Creams in bottom and Greens top. Greens wired in series, Creams in series and then both pairs parallelled for 16 Ohms total, I would think that wiring like this makes the speaker pairs affect eachother less than wiring pairs in parallell and then series.
@@jublaim I think I may have wired the other way, similar speakers in parallell so they look like one 8 ohm M and one 8 ohm H version; I'm pretty sure I felt very clever when I did it, I'm pretty sure I tried it different ways, and I'm pretty sure it makes very little real difference - no one ever came up to after a gig and said that they liked the way my speakers were connected 🙃. I do know that after I finished soldering it all up with big-bore cable, I felt such a sense of relief that I wouldn't have to think about it again that I was tempted to Araldite the screws into the back of my cab so I'd never be tempted to do anyting so tiresome again.
The amps negative feedback is only taken from one impedance tap. So if the tap has no load vs a load, then the negative feedback will be different. Hence maybe some difference in tone.
That makes total sense. Thanks for the explanation. To be honest, it's never occurred to me to use two different speakers in the same circuit, perhaps because I'm a bassist.
It really depends. IMO for most amps, whereas 4 ohms sounds clearer and brighter, w more detail, 16 ohms is warmer, less lively sounding and less dynamic; e.g. I have an 18 watt combo that sounds awesome at 8 ohms through a 1x12 but like muffly garbage when you run it at 16 ohms through 2x12's (ext speaker). Conversely, classic Marshall guitar amps are so bright, aggressive and "presencey" that they usually sound better run at 16ohms through either a 2x12 or a 4x12. That config helps to smooth & even out their almost shrill tones. I also have a 50 watt Marshall 1986 bass head clone that I use as a guitar amp. Way underrated, it's hotter than a classic Fender Bassman but mellower than a Marshall 1987. Stick a boutique dist pedal in front and it'll grind like any Marshall 1987. I've tried it through a 2X12 at 16 ohm and it just doesn't sound as good as 8 or 4 ohms due to its extended lows.
You are providing a valuable resource! I need to watch this 5 times
The 'jagged' portions of a speaker's output plot in the higher frequencies is caused mainly by cone distortions. It is not natural guitar treble. This is true for nearly everything above 1-2kHz! Guitar speakers are a very specialist component which leads to 90% of how guitar amps sound the way they do. Great guitar tone is mainly down to 'juicy' speaker cone breakup... not the tubes as believed by many!
"Let's assume they're (resistors) equal"... Huge save!! I like how you slipped that in to save the day!
Brilliant explanation of what has always been a confusing subject for me...it still is, but you helped me understand some of the physics behind the electromagnetism that influences the sound we hear out of our speaker cabinets. Physics is the foundation of our electromagnetic world, my father got his PhD. in physics and electronics, a dual degree - now I understand how and why they go together. Don't get me wrong, I'm a brain damaged drooling idiot, but I'm learning how my gear works, thanks to excellent teachers like this learned gentleman. I found this channel yesterday, when I was doing a search about speaker cabinets, since I was about to buy a speaker cabinet with a speaker inside. It was a killer deal, so after I researched it a bit and went back to complete my purchase, it was sold already (sigh). But now that I know about "Barefaced Audio", and I'm intrigued by their designs, I may have to buy one of their cabinets instead. I believe in paying for tone IF it really makes a difference, because it will be with me the rest of my life (probably not much left at my old age, but my tone is important to me while I'm still here). I long ago had too many guitars and amps, sold much of them, but then I bought more again last year, so not making much progress making room in the music room. Guitars and amps gave way to pickups and speakers (and cabinets). I've got a much better idea of how speaker cabinets and speakers work together now, thanks to you professor............cheers!
I've got a degree in Elect. Eng. Understood perfectly. I'll be parallel connecting my speakers in future. Great vid. Tx
honestly, I think any differences are in the output transformer.
if the transformer secondaries are all would in too thin a wire, then you would have a 16 Ohm tap that sounds better than the 4 ohm tap, ( typically the case, When it is a case )
but a good output transformer will leave no audible difference. ( that's where the ampacity of the windings are properly accounted for )
Thanks - Super explanation !........just great !
We are ALL different! The speakers are too! Give each a chance to do what "He" does best(Free Will!). So give them the same signal and see Who is standing afterwards.
there`s a lot of excellent reference work on " UNCLE DOUG`s" valve amp
repair and restoration channel if you hav`nt already found him, you will
be kicking yourself for missing this highly knowledgable fellow ! he is
the reference standard and a brilliant teacher in valve amp technology,
Excellent video! A good material for future experiments
Hadn't though about this, very cool, great video! It may help to draw out some equivalent circuits to show a static impedance at a given frequency and show the speakers as resistors acting as voltage dividers. I think that's an easier way to get your head around it. With regards to output transformer impedance taps, yes they definitely can and do affect the sound. Especially in vintage amps where the winding process may have been less exact with more variations in response and saturation on different taps. Not to mention negative feedback in the power stage and what impedance output tap that's connected to. All interesting stuff!
Good points!
My musicman HD130 pretty famously has series outputs. Such a strange concept to me
Fascinating stuff Alex, I never considered the interaction between two dissimilar speakers like that. Unfortunately zilla cabs have a TH-cam channel where they have many many videos of two speakers recorded independently and mixed together to help you in imagining the sound of blending those speakers but I guess the caveat is that this would only be close of they were in parallel wiring.
I've always thought go with the higher impedance setting, that way your speaker cable impedance has less of an effect on your sound (for long cable runs)
You'd need a very long skinny speakers cable for that to be a problem - not like with guitars where cable capacitance causes pretty obvious tonal changes.
Insightful! You should also consider mechanical compliance, plus electrical flyback with amplifiers which employ negative feedback.
Good content. I understand the explanation, but the reason I always wired my 4x12 speakers in series / parallel was reliability. If they were wired in series, a dead speaker meant a dead output transformer. That was a critical consideration as a gigging player on the road. 😬
I play bass (since 1961). I applaud your interest and your dedication, Keep on Keepin' On. (side note, we are speaking of a transfer of "feeling", right? What the player is trying to bring across, in Frequency to transfer the feeling to the listener (sympathetic resonance), what is the next step? We are speaking of selective "Vibration". A bass player is at "Home" in his envelope (very important on the stage...that's where we Live!) You Live in a "Transfer" World, what other ways can frequencies be excited in a selective way? Next step?
Thank you! That was a really good explanation, it helps me understanding what's going on. Now I'll go through impedance charts and try to make predictions...
Need an inductance chart too I would think.
@@Scoots1994 Being strictly scientific, that would definitely be the route to go!
Although we're dealing with a certain timbre and our own taste, so I'd be happy with just a prediction that would take me in the ballpark, avoiding unnecessary trial and error, then I'd make the final judgement with my ears only.
@@Scoots1994 It's really the impedance that matters, the inductance is just want causes that change in impedance (although in truth speakers don't have simple inductance because of the moving coil and all the metal around it).
Thanks! Great video!
Not to mention the compression effect in a sealed box meaning dissimilar magnet strength from the stronger motor will dominate the internal air and not allow as much cone movement in the weaker motor speaker.This in theory will exaggerated frequency peaks and dips in the stronger speaker cause its not equally dampened in the air chamber by a similar motor strength speaker
had been thinking on this subject lately, and one could come up with some interesting dynamics with a 4 speaker cabinet doing some series/parallel wiring. ie 2 8ohm speakers in series, and 2 different 8 ohm speakers in series, wire the 2 pairs in parallel....
Great explanation!
It's interesting this because with resistors in parallel, the voltage is the same on each one thus the lowest gets the most power and resistors in series, the current is the same through each thus the highest gets the most share of the voltage and the most power.
Impedance peaks like resonance may get exaggerated with different speakers. With the same speakers, each have (almost, manufacturing tolerances aside) identical impedance curves and thus will share the voltage equally.
Yea. You are very right.
When I was a child I did a test connecting two different speakers in series and in parallel. Serial connected they sound VERY weak, much weaker than a single speaker alone. I asked and I was told that it should sound as loud, if impedance was matched, but it wasn't the case. Now I see why.
When there are four speakers involved we can connect them in series and in parallel at the same time,8 getting 8 ohms as total impedance, assuming they all are nominal 8 ohms.
"Serial connected they sound VERY weak", you may have connected the speakers out of phase (like + in on first speaker, - out of first speaker to - in on next speaker). Just connecting speakers i series should not result in a drastic lack of output volume.
@jublaim This was a long time ago, and I can't remember every step of my tests, but I'm pretty sure that I tested them both ways. In phase and out of phase.
The dynamics of membranes made of paper connected to electromagnetic coils moving according to the soundwaves under half voltage or full voltage must be more complex than we think.
My tests told me that serials connection wasn't efficient.
Right now I pair a Alnico Creamback and a Neo Creamback in an oversized open back cab and it sounds huge.The reason why I prefer series wiring is I get a 16 Ohm cab and can pair it with another 16 Ohm cab to get 8 Ohm in total - what most amps can provide..
This video is great and understanding
Most traditional solid state amps, have very high levels of voltage feedback in order to stabilise them by design, hence at resonance the output gain is massively reduced producing the more mid focused sound most associate with cheaper/traditional solid state designs. Amplifiers designed with a portion of current feedback can be designed to sound much more like a valve amplifier, in that they do not track the impedance curve of the speaker in the same manner.
In that respect they would have a lower damping factor, much like that of a valve amp, the speaker is not clamped down by the output impedance of the amplifier to the same degree. This more ballistic behaviour is what people perceive as the valve sound. Putting speakers in parallel was the old world way of damping them for Hifi as their different resonance, impedance and phase angle had that limiting effect that the then valve amplifiers could not achieve. On the other hand putting drivers in series decreases damping as it makes the series impedance of the amplifier look much much larger to either of the speakers hence reducing the damping.
In a valve amp with an output transformer the change of impedance ratio by tap has a huge effect on the amount of voltage feedback, and thereby the gain of the power amp and damping. All bets are off in comparison, there are so many elements at work!
It’s a great subject for discussion but very hard to demonstrate without a proper level playing field.
Love your content, I’d very much like to try one of your cabinets one day. All the best from Wales!
I dont beleive its the case that speakers in series are less damped because they are moving in sync and hence generating a mutual back EMF. Yes if only one speaker was moving the other speaker would act as a passive serial impedence reducing damping but that doesnt happen because the speakers are moving together.
@@pncampbell sorry my battery went while I was replying. Thanks for your response that’s got the old grey matter working. Yeah that’s a great point , I would imagine though that if overall system damping was low enough and there was enough difference between the two drivers resonance and breakup modes then the back emf would not be equal.
I got some really erratic variation when testing different drivers with a power amp with mixed mode feedback to raise the output impedance for a lower damping factor. I wanted to test it further at the time but the parties involved felt the returns were diminishing for the proportion of effect on the results. This was in parallel though.
I may set up a test for my own ends when I get a minute.
@@PoJoWo No worries, I was assuming two identical speakers, yes the mutual damping would get interesting with different ones in series.
This was super interessting! Please do this video with bass speakers aswell. Just for "fun " ;)
Fascinating. I had no idea the interaction would have such an effect.
So, if you had 2 of the same speakers there would be as little effect as you could get.
I’ve been thinking about how transformers play a role in sound production as well.
Some of this is probably cork sniffing because these things don’t exist in isolation.
There’s no way to figure out optimal sound-it’s too complicated. You really need to go with your ear.
Thank god I have an amazing sounding cab…I don’t need to worrying. You guys did a great job.
With two identical speakers it shouldn't matter how you wire them (ignoring amp issues!)
I noticed this too! I didn't like the way my speakers sound in series.
Really interesting Alex, starting to unravel the voodoo and witchcraft surrounding the subject. Great work (as ever!)!
brilliant.
the guitar (and bass ) world needs more facts like those presented in this video.
in a way, the series connection is creating a very crude crossover style network.
I did a few simple measurements today with an LCR meter, and I think you maybe should have taken the capacity of the speaker into consideration also. Maybe that will cancel out the differences.
I measured a Celestion and a WGS 8 ohm 12" speaker alone, in series and in parallel:
Celestion: 6.95 R / 34.6 uF / 0.71 mH
WGS: 6.85 R / 38.5 uF / 0.66 mH
Serial: 13.89 R / 18 uF / 1.44 mH Double / half / double
Parallel: 3.58 R / 72.7 uF / 0.35 mH Half / double / half.
That was as expected, but I wonder what it tells us? This is not criticism. I am also very interested in this topic. And I also have time issues, but will probably do the freq. measurements soon.
At 14:50, you say "Your amp should be a voltage source", but most guitar amps are not voltage sources. Pentodes and beam tetrodes are pretty close to voltage controlled current sinks in their linear operating range. A push-pull EL34 power amp with zero negative feedback has an output impedance on the order of 100Ω (8Ω load). With negative feedback, the output impedance drops significantly, but is still pretty high. Presence and resonance controls reduce negative feedback at high and low frequencies respectively, so output impedance rises over the range they act on as you turn them up.
Another way of thinking about the difference between series/parallel is to consider the current. Series-connected speakers must have identical current, but parallel-connected speakers can have different currents. Strange stuff happens with the total impedance around resonance in a series-wired circuit if the resonance frequency of the two speakers is significantly different as there will be a huge mismatch in electrical phase between the two. At high frequencies, the electrical phase will be similar unless the Le values are dramatically different (not likely in a guitar speaker), so the (scaled) total impedance isn't much different between series/parallel wiring.
Regarding the output transformer question: There will be some difference in parasitics between the different taps, but I don't know how audible this might be (or if it's audible at all). Secondary winding resistance will be higher relative to the load impedance for lower impedance taps, while primary-secondary capacitive coupling will be lower. Secondary leakage inductance will be different as well.
This is great, thanks for the expertise!
I’ve heard blind demos of series vs parallel speaker wiring. You are correct there is a noticeable difference. Series wired speakers are definitely not my cup of tea. As for output from amps I have a Bluguitar Amp 1 it has a valve in it for the power amp but it can be run not connected to a speaker (it’s German they think of everything like guitar players doing stupid stuff) it has a 8ohm and 16ohm output if I run 16ohm into an 8ohm cab it sounds quieter and if I run 8ohm out into 8ohm cab it sounds louder also it similar in tone to using the high low guitar input sockets you get on some amp’s. That’s all I know.
Interesting video.
The biggest reason why guitar players think amplifiers sound different at different transformer output taps, stems from Marshall back in the day erroneously wiring the negative feedback loop to the secondary side of the output transformer. So as you chose different load taps depending on your speaker cabinet impedance - you were inadvertently changing the negative feedback value at the same time. The second you corrected Marshall’s wiring mistake, no audible changes occur from using the different taps.
I am sure you are not right here. When for instance you put the FB on the 8 ohms tap, you will always get the same FB, no matter which speaker tap you use.
All amps makers do this till this day. The more likely reason could be that that there are more / less windings on the different transformer taps, and that the
same is true for speakers. The same type speaker in 8 ohms or 16 ohms will sound different. It is obvious when you check for instance Jensens speaker
datasheets.
I’m guessing here, but would the negative feed back signal/characteristic be altered depending on whether or not a speaker was connected to the same transformer tap ?
@@chrisstevens4680 I've modded an amp so I can switch NFB tap between 4, ,8 and 16 Ohm and also choose different NFB resistor values. I prefer to tap NFB from the same Ohm as the connected speaker cab; it sort of gives a richer sound. It's not a huge difference but it's there. My take is that this makes the speaker(s) interact more directly with the amps NFB circuit.
@@jublaim that was my thought exactly. Also, I haven't checked yet, but I am assuming that there will be different voltages on each tap and hence a differing amount of NFB. I was building a Marshall Plexi clone but have had to put the project on ice for the last year. I will carry on with the project later this year and do the same experiments. Which amp do you have, are you going for distortion or clean and which value of NFB resistor have you found sounds best?
@chrisstevens4680 The amp is a Marshall JVM Satriani model that's been my modding victim for nearly 10 years now. I mainly go for distorted sounds. With the 16 Ohm 4x12 I use NFB from 16 Ohm tap and 200k resistor, this gives same NFB as original 100k from 4 Ohm tap. The feedback calculation is: double the output Ohm is increasing NFB with a factor of 1.41. From 4 to 16 Ohm the factor is 2.
This makes so much sense! I can hear an output difference between my 115 and my 4x10 hartke Ak cabs. I felt like it was because of the paralell 15 and the series 10s connections. But had not the knowledge to explain it. Now i do. They both produce an very equal output spl wise but when run chained the 2 cabs sound brighter in different arwas of the freq spectrum. If you stand back 5ft its barely noticeable. But right up close there is definitely some subtle differences.. This explanation helps a ton in mmy future speaker ideas as well! Great video now if i could only save enough cash for a Barefaced 8x10!!
When they’re daisy-chained they’re almost certainly in parallel so there’s something else going on. But there’s a lot of variables when combining dissimilar cabs!
@BarefacedAudio Thank you for the response! Just a thought. Running both outputs of the amp would it make the most sense to do 2) 1x15 cabs 1st output and then the 2) 4x10 cabs on the other output? Both sides 4ohm load but not combining two differently wired cabs.. I'm close to what I want bit still missing a piece.
@@brandonacker3290 what’s the amp?
@@BarefacedAudio a traynor yba 300
My main goal is a larger number cones to move more air and hopefully have higher spl with not as loud of db I know the two cannot be separated but that's the path my mind is on. Is it possible that's its just the overall differences in the mechanical parameters of the speakers that make the frequency response noticeable to the ear? Best way to say it is both cabs reach a similar output level but the 15 and 10s seem to push harder in different areas of the spectrum.. Thank you for even responding! I watched a few of your videos and it got my mind going even more. It's amazing that things can be wired to work but are not "correct".. thanks again!
Mixing speakers in a bass cab can sound great ever heard mesa Boogie 1516b road ready series 1x15",1x10" 1x4" and horn tweeter.
That is not the same as two speakers without crossovers. Crossovers in layman's terms control which frequencies go to which drivers and divides the amount of power distributed to each driver. I have a lot of experience designing crossovers and this is a very basic way of explaining it.
Great video, as always 👌 My JVM 205C has (from factory) two different 8 ohms Celestion speakers (Vintage and Heritage, Marshall branded) connected in series, so they have 16ohms combined... Wouldn't be strange to connect them in parallel and get 4ohms?
Certainly worth trying!
Hmm...I had always wondered if running different speakers in series had a "chewed meat" syndrome where the 2nd speaker is getting "used" and worn out electricity from the other. I knew that wasn't the case but I love the concept of used, dog eared voltage. Your example of a voltage divider is an easy concept to grasp . Another way of looking at your explanation is that series components see identical current (by physics laws) all the time and if one speaker has a change in voltage drop with a change in frequency that affects its sound, and the other speaker reacts differently, it makes sense that they affect each other because the reaction current one makes alone is affected by the other. Well done!
Yes, it was the current thing that got me thinking.
What you will do is change the power draw at different frequencies and thus the frequency response. For example - the resonant frequency of each speaker could be different and the highest impedance speaker at any one time will receive the most power in series (compared to the least power in parallel) which could exaggerate the frequency response as resonance tends to be quite efficient in terms of absolute power.
I paused right at the beginning to say that I have a problem that this fits perfectly. I have a 2x12 cab that is parallel but the impedance of the speakers doesn't match my new (vintage) head. If I change to series then the impedance WILL match my head. Now I get to find out what that will mean, let's watch shall we?
...
Okay, got to the end. I understand it, and now I have to go look what speakers are in my 2x12, I know they don't match but I don't know about their inductive differences. They sounded great with the Soldano in high gain sounds in parallel but my new head (JCM800) I was going to go for more rock sounds. So this is going to be interesting. I knew it made a difference to the sound but didn't know why.
So 2 of the same speaker it will make no difference or little difference but dissimilar speakers it will. That's really interesting.
Experiment and report back!
What you're saying is very true. However, transistor amps are mainly 'constant voltage' amplifiers and valve amps are 'constant current' (CC) amplifiers. This will make further HUGE sonic differences that you have not considered. With 'CC' amps, the output transformer's internal impedance has to also be brought into the equations. CC compensates for the speaker's varying impedance and results in a more constant output level across the audio band... it's what makes the 'valve amp sound'!
In the guitar world, many modern transistor guitar amps now incorporate 'constant current' techniques which enables them to mimic a valve amplifier's sonic superiority! This is a very important topic to cover and explains why the 'old design' tranny amps sound cold and less loud/dynamic. BTW, I am an amp designer. Get in touch if you want to know more about this CC business!
I shall email you - I was actually reading through your website a few days ago, having been led there whilst researching pickups!
But i think this CC hapens more or less on a primary side of an output transformer...
@@BarefacedAudio I didn't hear from you.
@@ggmobi5817 No... CC happens exclusively on the OPTX secondary. For it to take place, CC depends on being able to monitor the speaker's changing impedance and reacting accordingly. This can ONLY be done on the secondary side. That's why all our solid-state guitar amps are equipped with 'RetroTone' which produces the same performance, tone and dynamics (loudness) as a tube amp. It's the dynamics which makes a tube guitar amp appear louder, Watt for Watt, than a solid-state amp. CC corrects this and makes solid-state amps as loud as a tube amp. All the old 1970s HH solid-state amps were CC enabled... think Wilko Johnson's tones! And boy, those amps were loud!
I do PA on an amateur level. I've learnt from helping professional sound people. Id never dream of wiring drivers in series. Then again, I'd always run with at least 25% headroom on the amps. This stops the amp sending a clipped signal to the driver, which would over heat and break up. hadn't considered the rc flitering effect on the tone of each speaker if mixed. Which is the opposite of over driving guitar amps with drivers having a bigger rms than the amp, which is what guitar rigs do? Isn't it?
Great explanation and because it is approached from a physics point of view it takes away the subjective aspect of taste and hearing.
Can the difference in tone caused by different size voice coils also be applied to bass speakers?
Inductance changes the response of all speakers - but with guitar speakers you have the least wiggle room to adjust for it with different design approaches because guitar speakers are just really rather strange! (The sound of electric guitar is to quite a large degree the sound of fairly large light paper cone loudspeakers designed and built with decades old technology, with all the "imperfections" that causes)
I understood it, but I hadn't thought about it before. The most I thought about speaker wiring and impedance was mixing/matching series and parallel to get the impedance for the cabinet you were looking for. The Series example seems to show that the speaker that is worse at reproducing highs is now doing it, and the one that's good at it is not? Did I get that right? And what if you swapped the speakers, would it go back to looking more like the Parallel example? My depth of electronics knowledge didn't go into this and was a good while back. I guess I'm trying to ask is does the order of the series speakers matter?
Good question. I would guess the order does not matter.
@@Scoots1994 exactly.
Do the amps push voltage or do the speakers draw voltage? Sorry it's been decades since university physics. I suppose, in parallel, a pushed voltage would mean the speakers reacting the same right? If the speakers are drawing the voltage, then wouldn't they sort of split the voltage with each other in a 1/V type of way?
I can't imagine someone hooking speakers in series; the two speakers will starve each other of power where and when they need it most. I just built up a four speaker cabinet and each identical speaker is 16 ohms (in parallel, of course) so I'll end up with 4 ohms. What surprises me most is I've never heard anyone talk about this before when it is so obvious and common sense if you understand ohms law.
Yes, around resonance it's certainly a weird thing - but I guess not a lot of guitar tone is happening down there, plus rooms are weird at those frequencies and guitar speakers are very non-linear down there too, so it gets hidden.
I come from a PA background and would never ever wire in series. Then again given that less ohms equals more power, this is how a PA should be wired. Plenty of headroom, ie the rms of an amp being greater than that of the drivers.
I know in the esoteric tone crucial world of guitar often the reverse is necessary. I've always assumed you guys have magic amps and super strong drivers to take all that abuse from being overdriven. Maybe some cabinet builders, when mixing drivers, play white noise through them and using a mic do a spectrsl analysis, to ensure that you get a great tone? I also know damn well that many won't.
Like I say, what you guys do defies my perceived wisdom. You do things I couldn't and wouldn't dare do. I've seen smoke coming out of overdriven PA cabs and someone having to unload a fire extinguisher into one of the ports.
@@stuartchapman5171 head room isn't about amp size vs speaker size. It's about how loud amp and speaker can produce, vs how loud your gig is. Oversizing amps gives you the most clean performance out of your speakers as long as drunkards are away from the volume controls. It will give you a clean sound right up to the point the speakers blow (or ensure any bad sound is from the speakers being worked too hard).
Undersized amps mean the amp is the limiting factor and is the "safe" option although a heavily clipped amp tends to funnel a higher power percentage towards the tweeter and midrange drivers (although it usually sounds terrible at this point).
@TimpBizkit it's almost a different strand of the same science. I've provided many PA for lots of styles, from free parties to big clubs to Nottinghill. I've only had 2 driver incidents. I still struggle with the concept behind speaker cabs and amps, designed to be overdriven, channel strip yes, amps, not in my world.
I know a lot of guys who are heavily into backline and don't have a Scooby about PA.
Hats off to you for having a grasp of both.
It's too much of a learning curve for me to encompass backline tech. I'll continue watching the videos though.
The guitar is probably the oldest electric instrument, it follows that tone hunting is highly honed in that world, plus I use lots of pedals in my sound design work.
Maybe the penny will drop one day.
@stuartchapman5171 I'm more of a hobbyist, but PA is about clean reproduction (though in practice most speakers dedicated to getting loud will be coloured compared to a good stereo at home). You are not deliberately using the amp and speakers to impart a timbre to the sound like a guitar speaker. As far as overdrive, it compresses the average power, meaning just oversize the speaker capacity compared to the amp.
In terms of power handling and blowing speakers, you have to think about how much power - peak and average and in what frequency band relative to the drivers on the speakers and what the crossover settings partition to which driver. In terms of low frequency, the practical limit is not a -3 or -10 dB but at what frequency the cone unloads and starts flapping around - if you go too low with a horn or ported box. Some designs unload near their -3 others keep the cone under control but lose output but can still be used so long as you don't excessively boost.
There is more going on regarding changing impedance,depending on the type of amp. For example a amps negative feedback (if it has one) will drastically vary depending on how it’s connected at the tap. I’ve always believed that using two different speakers in parallel smoothens out each other’s bass response through damping? Am I wrong here?
Negative feedback point is very good! And the point about different speakers in parallel has got me thinking - and yes, you could be onto something there, if by "smoothing out bass response" you're referring to reducing the efficiency down there so causing the lows to roll off sooner with lower Q. Very interesting!
Thanks for your reply! I was definitely talking about how it changed the q of each speaker yes. Would love to hear a break down from you. Great videos by the way..
Quite interesting !Does the order of the speaker create a different reaction in série ?
No.
Yes, but then, what if you have two 2x12 cabs (both having 16-ohm speakers wired parallel - so, 8 ohms per cab) and then join them in series, so that you in effect have a 4x12 at 16 ohms total? Answer that one, smarty pants. 😂 (kidding)
Depends on what all the drivers are - but that’s standard series/parallel wiring! 😉
Guys dont mix them in parallel either. You get the same impedance problems and again one speaker will be more pushed at certain tones and the other at different ones. In any case impedance of the speakers must be as same as possible to the output impedance of an amp to get max effect- power on the loudspeaker(s).
This isn’t correct, sorry!
@@BarefacedAudio Im opened for an explanation....
@@BarefacedAudio my logic... You have an 1 ohm and a 2 ohm impedance speakers in paralel to 10 V source. 1 Ohm draws 5A and 2 ohm draw 10A. (50W on first speaker and 100 W on second one) Amp must supply 15 Amps on the output aka 150 W right?
@@ggmobi5817 Sorry, I was talking about mixing speaker models, not mixing different impedance speakers. But they're reactive loads and impedance is very much non-constant, changing hugely with frequency.
@@BarefacedAudio I just made this 1 and 2 ohms as an example... We all know that different speakers with same nominal impedance vastely variate in actual impedance, so at the same frequency it can be much different and... You get my example.
Good talk, good talk, yeh, yeh.
So what about when 4 16ohm speakers are wired to 16ohms with 2 different speakers, will this affect the sound of the speakers. I am thinking of combining 2 celestion cl80's and 2 neo creambacks into one 4x12 because I like the low end of the cl80 and the top end of the neo. Will I lose anything from each speaker combing them or should I keep them in separate cabs.
To preserve the individual frequency response curves as best as possible, put the 2 Celestion CL80 speakers on one series loop together, and parallel with the two neo creambacks on another series loop. I mean there might be other interactions if you have a shared airspace, but electrically this will ensure a 50:50 voltage share if you are series wiring speaker sets with identical impedance curves.
Alex, how cold is it where you do these videos? It looks like you are wearing several layers.
What effect does temperature have on cabs/speakers? I would guess at extremes the response would get very slightly muddied.
We don't tend to bother with heating in there so it's approximately the average outdoor temperature plus however much heat any humans/gear has point into the room - I put a thermometer in there after you asked and it's been 13-17C (ask google if you need F). It's sunny and warm outside now but it'll take a while for that room to warm up, as it's like an insulated concrete bunker. Temperature does matter with speakers but not in the way you're thinking - another video (or many) in that!
That is very interesting, but theoretic. Why don´t you back it up with a few measurements? All it takes is a PC with a decent sound card, a USB measurement microphone and REW, a free
program that can measure speaker responses. Then you could try a solid state amp and a tube amp and see if there are differences. The proof is in the pudding I think British people say 🙂.
I've got all the gear to do that - what I don't have is time (that's why there haven't been any new videos for months, too busy building cabs, etc!) That's also why most videos on this channel are done as-live, zero editing. Never enough time!
So if: a 4x12 is wired parrallel with two series circuits, and i should use 2 different speakers, the same pairs should be wired in the series circuit? (positive > split to circ1 and circ2 > circ1 containing v30's > circ2 containing gt12-75's > circ1 and circ2 joining again > to the negative)?
That's a great question and a logical solution based on this info!
I think it depends which sounds better to you. I've got some experimenting to do myself.
Jens-- if you’d like to retain the natural frequency characteristics of the speakers 🔊, wire the same speaker type in SERIES, and then wire the pairs in PARALLEL.
Example: V30 + V30 in series….. G12t-75 + G12t-75 in series….. V30 pair + G12t-75 pair in parallel.
Hope this helps! As always…. No rules- just conventions & practices 🤘🏽
4ohm sounds different to 16ohm and 8ohm sounds different again....with the same amp...
So we should go for parallel if speakers are different right?
Nope.
I already did 😅@@ggmobi5817
Are conspiracies usually wrong? 🤐
Recently a lot seem to be right! 🤔
That was indeed a strange conflation of issues. Can we call this a Barefaced lie?
To add, it all depends on the evidence provided. Some conspiracies are exactly that. No need to fill in the blanks yourself.
Lol.... Well, there were, are and will always be intentional political conspiraces. But the world as it has become over the past few years - some conspiracy theories are well & truly rooted in facts anf founded research. Which all gave rise to... 'about 3 to 6 months is the difference between conspiracy theory and truth'. 😁
LH side audio only? Thought Id gone deaf!!
Sorry about that - just checked on headphones and you’re quite right! I think the stereo lead from mic to camera must have been pulled halfway out. There is (much quieter) sound on the right but that must be crosstalk from the left channel. Will make sure that doesn’t happen again, thanks for letting me know!
awesome....guitar tone is all about physics, not the actual real tone....
You have just opened up a huge tin of worms for tone tweaking.
And now I have reached the end where you allege that the speakers will be dealing independently with the same voltage. I’m sorry but that is false. They are not independent at all. They are still interdependent. I invite you to put a microphone on each dissimilar speaker wired in parallel (I have edited this comment to change series to parallel there). And you can account for variables by moving the negative feedback loop (and its resistor) tap to different taps on the output transformer to accommodate the changing impedance as you select single speakers versus both.
At least one who knows what he is talking. Not like shreding dudes knowing shit about phisics and selling their "knowledge" which destroys your sound and equipment.
Bloody guitarists...🙄
Just plug in and play, stop faffing around looking to change the world.
You'd never hear of us decent folk (bassists) yanking out drivers from our already superb cabs!
Just leave it alone and go practice 😂 🤣
(yes, I did follow the logic of the physics/maths but then again why would you... ?)
Some of us bassists like to noodle with guitars too. They are both full of rabbit holes ... just different ones. :)
The difference is that tons of the tone of electric guitar is actually the tone of the speakers. Whilst most of the tone of bass guitar comes from the bass itself. (Which begs the question, why do guitarists not spend more money on speakers than guitars?)
@@BarefacedAudio worse than that, many guitarists don't value the speaker's part in their tone at all, often putting it on the amp. Bassists are easier. I love my Orange Thuderverb 200 but I can get my sound out of most amps for bass.