8th Order Bandpass (Explained): Part 1
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- เผยแพร่เมื่อ 8 ก.พ. 2018
- In this video I explain the basics behind building an 8th order bandpass enclosure. This is a direct followup to my 4th Order vs 6th Order Band-pass video. Follow me on Twitter @budgetbass
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Bruv. At the start of this video I could not even imagine how an 8th order bandpass would work. Now. I understand exactly. Thank you for the information and keep up the good work.
YesNoVideo b*
Is this more or less efficient than a straight up ported enclosure, can it reach lower hz than a ported box of the same volume and same driver?
Thought Steve Harvey was making the video at first
BLK Ceaser sounds like family feud lol
Haha
Hahaha
i still do after all this time
Great... I cant unthink / hear it now..
This is the best explanation of the purpose and Design of a high order bandpass subwoofer on TH-cam. Well done
this video was really helpful. i’m running a Skar Audio SDR 12 in a box from the same company. I was looking into getting two 15’s and putting it in a 4th order box. After watching this, i’m gonna put them in a 6th order band pass. Thank you for making this, people like you who take time out of their day to do these things really helps us begginers get into car audio
Welcome to the channel Thanks for the support 🤟
Very informative man thank you. I've been in the game for over 20 years as the garage diy guy and now get what different order builds are capable of.
The saying "there's no replacement for displacement", this is exactly it. To get the most out of a sub, you need a big box. Sure, you could throw more power at it, but its a ton more for saving a bit of space, upgrading alt, batteries, wires, and buying a more powerful amp can be replaced with some more wood. My 15" sub in a 300L box performs 5dB louder than it in its old 100L sealed box. Doubling the power only gets 3dB, so its as loud as 3 15" subs in a total of 300L of box. Just goes to show how efficient 6th orders are. Keen to see the result of this 8th order, subbed.
UniCrafter Thanks for the comment. Well, explained!
BudgetBassHead ok but what about high rated subs like 2000rms. Would you recommend?
@@workinprogressharris6416 i would say 2kw are pretty normal for a setup something like 5k is bigger but nothing crazy
This is very well done. You did a great job. I learned something I had no idea of that may have taken me years down the line to even been curious about.
I really appreciate your video. you said many times a subwoofer can play below resonant frequency. people usually judge a driver by it's xmax, power handling and fs. all of which means nothing without a proper enclosure. great info bro.
has anybody ever told you you sound like Steve harvey. lol great video
Excellent explanation! I've always liked 6ths so i think I'll give this a whirl. The engineering is quite straightforward. I explained it once as it being as a "bandpass filter such as an LC (inductor cap resonant filter network) for radio use. (I do radio work as well as car audio).
Damn good explanation ❤️
From Botswana 🇧🇼🇧🇼 with love
I would love to see a response curve of that box. I think that it is an awesome video and explanation. Ready for more!
Got a video coming soon of the software. That would be vid #2 of this
I wanna see some tests!! Show the stuff in the real world!!
I'm glad you're talking about this, I think you'd like the "master handbook of accoustics" by floyd o tool. Also I think octaves would be an important consideration in tuning the ports. I would also think that once you add the 70hz port that it would change the tuning of the inner ports with the added length.
Dude I know these videos are old but I love this content I love audio I'm an audiophile and part time bass head when I wanna have fun listening to music and not be so technical but this is teaching me so much!! Never knew half of this shit existed I wanna hear them all. I wanna hear the horn enclosure the most. If they use horns at concerts I love that type of bass.
Thank you for making a great video on 8th order bp boxes. Careful with port placement, it looks a little close to the red panel causing an unexpected extra port to form inside the box that will usually ruin the sound
I totally fill what your saying, and it Is a good way to explain it to newbies. I love the low low htz. And cheaper subs with a high res for some reason I end up with voice could jumping out of the motors lol. I have subscribed to keep up with what your up to. I'm working on a design for a motorcycle that hits hard not just screams with mids and highs lol.
Instantly fell in love with your content, looking forward to checking out more of your videos
Thanks for the support 👍 And welcome to the channel!
For every bandpass system, there is a gain-bandwidth product that is a maximum for the system, so you can either optimize for gain (in this case, resonant gain) or you can optimize for bandwidth, and any time you restrict the bandwidth of the system you increase its gain. The more sharply the response of the bandpass box is cut off at either end, the more extra gain you get. As you play with chamber volumes and front chamber volume in a 4th-order bandpass, you can see this at work -- certain combinations of box volume and tuning give you a narrow, tall peak, and other combinations give you wide bandwidth with less gain, with the ideal being some compromise between the two.
essentially looks like coupled resonator bandpass filters from the analog domain. as you adjust the coupling, ripple, and losses, you also change the bandwidth and efficiency (ie loss)
You've inspired me to build a bandpass box thank you your explanations are so great and easy to understand
Didn't understand a bandpass b4 so thankful now great video
There IS NOT enough content of 8th orders on TH-cam.. please make this box and share everything!
Video coming soon.
I want to build a 8th order box, i love my bose acoustimass 5 serie 3 its a 8th other its so strong in the sound for 2 5inch woofers even at 25hz i love that thing.
I want to build 1 dual 10inch tangband or 2 single 10 boxes ( i already have the woofers)
yurian: go right ahead.
The bose box is the way to go
Man, dudes got mad skills 💪😮super intelligent and impressive AF ❤
Yo that box was the shiznit bro im gonna try and probably fail to make a 8th order that makes sense the way u explain everything to awesome video my friend thank u 💯👍🏼👍🏼✌🏼💪🏼🔈💪🏼🔉💪🏼🔊
So what I got from this is buy a quality 10in sub and build a nice 4th order! 😁
Bro, best explanation ever
Just watched your entire series on 4th vs 6th and it helped me fill in the gaps. I'd love to see you do a video on passive radiators. I've been learning everything I can on them and will be doing a build with an active RE XXX V1 18 and two passive Dayton 18s. It might turn out like shit but it'll be a learning experience.
If it turns out like shit I'll take a RE
Funny you talk about quality in the components, I actually bought some (I thought decent) Polk speakers for my car, but what has happened is the suspension has gotten dry rotted after only 5 years! The old speakers had a sort of paper suspension and these ones were a very supple rubber, I thought they'd last a good long time, but I guess the heat in Florida is just too much. Also I'd like to say I didn't do anything crazy with these speakers, I literally just replaced the 6 inch in the front door panels and the 3.5 inches in the dash of my car after the old ones tore the suspension.
I want to add a infra sound sub in my house. that peaks at 10hz. maybe a 12" in a huge box. band pass. of some kind. and a 12" in a sealed enclosure . for 30-100hz. the low low sub for infra sound . should play 30hz and down loud enough. I know you stop hearing sound from 22-18hz. but you sense it with other senses. even your vision . I think some movies will benefit from some lo low! choppers planes explosions and music. should be awesome. and some 5 1/4" coaxial mids . and 6.5"-8" mids. and tweeters! surround sound. with center channel. I'd say under the couch would be a good place if it would fit. that way you are close to the bass. or behind it. yes I'm rambling again. after I told my self I wasn't going to do that anymore... great video.
U can hear 20Hz and feel it also. When u can hear it with sufficient spl it's beautiful.
A bass horn or TL would b the best box for such a task
I have 12 15 s in a bandpassbox in my basement,it’s fucking amazing, BUT , my wife never lets me play it , all her shit falls off the walls and tables and breaks 😩, anything above 120 dB in house destroys everything
subscribed!! thanks ..alot of info!
General rule of tuning is a octave apart.30/60 etc.
Exactily
I know that’s true for a 6th order but what do you tune the common chamber to?
I Love my compact 6th order. Like a snail shell!! So if this is how you are thinking we gna going to have a great bond.
Thank you for your information I received that
Good work.... ✌️
man you'r great ..thank u thank u that's really great
okay dont tell me, next your going to say , "coming up next is a 10 order" "made out of good stuff".
let me know when you get to the 15th order alien good stuff schematics.😳
32 order bandpass single subwoofer. need to have a semi truck and use the whole 53 foot trailer for the box
Man i love your explanation of things "simple and direct" so please explain to me box rise
"box rise" is a mis-nomer that originated in the car audio forums to attempt to explain the characteristic that is simply impedance, which is a frequency dependent resistance with peaks, corresponding with different scenarios. The funny thing is that even *without* the driver being *in* a box, there is still "rise" because of the driver's natural free-air resonance. You might find that weird, but it's true because it is an electrodynamic system that has a coil immersed in a magnetic field. This kind of explanation is best left to the experts.
You can't adjust box rise. Box rise exist with or without electrical power, box rise is never consistent.
Box rise should be ignored.
The new Hornresp versions can model these, but in modelling I found best response was with the outer port tuned between the two inner ports, rather than my intuition telling me to tune it higher than the others. This gives three peaks and then you can play with the sizes and frequencies to get it flatter. The outer port also has to be big area so it doesn't low pass out the higher frequency inner port, and also because it is the sole source of sound into the room.
Also, the inner ports will act as a different length depending on the outer chamber, so it's quite hard to build if you are just calculating helmholtz resonances for a parallel 6th order, because they will change when fired into a common third chamber. It's like the inner chambers have a long port that expands into a space and contracts again. Also the airspace in the box will add additional airspring, so in essence the internal ports can both be tuned lower and higher.
Great tips
Great video dude!! Im subbed to u now, bassheads stick together!!!
Good stuff.
I’m not sure if the math works like this but for both the internal ports would the 70hz port technically be extending them lower since it’s make the port even longer ie the 50 and 70 would come down to 20 and the 30 and the 70 would come down to 40 the math might not work out entirely but would that atleast be what is happening here
You have a way of explaining the most complex details most of us wouldn’t EVER be able to comprehend in a way that we can actually retain and utilize... thank you, sincerely bro.
That said, is there a way to contact you for more personal design build thoughts and design parameters?... I’d greatly appreciate the opportunity and advise. Much love, keep puttin’ out tha knowledge
Ik
I want to experiment with sealed 50hz side of the 8th order box. Leave the 30hz open to the 70hz port but seal the speaker face side.
I dropped a subwoffer in a Djembe sub and sealed it with a gas line I glued into a perfect gasket. It definitely does an anomaly sound boom. Upright it's sealed and on its side its ported.
Thank you BBH
I would like for you to make a video explaining how the sealed side of that 4th and its size offsets tuning
Video Coming soon
Mr, Harvey in the house!
How does the port tuning impact final output? I’m trying to figure does all the port frequency play well ? Or just final outside port?
In order to know this, you have two choices. The easiest choice is to get familiar with a software that does all the hard work for you; and tells you exactly what your tuning should be. The more challenging option is by trial and error. get your feet wet and make some mistakes until you learn it without even thinking about it. To start out, just tune it to the manufacturer's recommendations and adjust from there.
Bro your Steve harvey impression is spot on. You should get paid for this shit
In my mind, hatever happenig inside the box , would not matter would it at the only sound that is coming from that enclosure, is what comes out the last port, green seventy herz? thus u would only hear the common loud but narrow seventy herz band of audio as the woofer is on inside of box as thay are in bandbases.. the only other sounds that would come would be the other resonant frequencies from the seventy herz port tuning which are the notes on the sine wave looking graph of a seventy herz soumd wave..the nodes ate the top apex of the compresion positive side the node at the neutral dead center of the wave not positive or negative but half way mark of the wave then again at the botomtom of the negative wave ..or one fourth, one half three quarters points of the sine wave would also resonate if my understandins are correct.. that woofer could be distorting in side box but u only hear wha the port tube rosonates from it???
Anthony Jackson uses a sub with his two twelve sealed box in concerts and it sounds very good.
One thing for consideration:
When a driver/woofer/sub is put into an enclosure, it's like the box is a component of the speaker. Kind of like the flared end of a trumpet is a part of that instrument.
also, the flared end has a lot to do with how the inner chambers are coupled to the outside chamber , ie the air around us. The flare improves the efficiency (ie coupling) which is why a tuba or trumpet is so loud as compared to just the mouthpiece of the same tuba / trumpet
Hey bro I have a Orion’s 15” am I don’t know what kind of box to bill so can you please help me out here thanks
Have you ever looked at Bose sub designs ? Most of them are 7th order bandpass designs with a dual or triple sub configuration the newer models are transmission line designed. The original Bose Acoustimass 3, 4, and HT use a 4th order band pass I believe.
Good points
ok 2 questions- in your example of 4th order- is the speaker not loaded backwards? i thought the point of the sealed enclosure is to prevent over excursion. second- why/how is the exit of the enclosures so close to the driver? wouldn't the air flow just bypass the entire enclosure and go straight out the exit?
Ibreally dig your videos, i have learned so so much but question. Could the front wall move in on the 8th and replace the port wall?
Not sure I understand the question
Never seen or herd one.But it looks good.
You should put that inside another ported enclosure to to make it a 10th order, then inside another for 12th etc, with increasing output at every stage, of course. ;) Would be funny. Might even become a nice little meme.
Wouldnt that whole box just be tuned 70hz since thats the only port the box actually has
Yes. I think logically the same.. all enclosures . Should have their own port direct out out of the box .. he is thinking inside the box instead of outside the box 😉
Hi 😇 Thx for your very good video series. 🙏 Can you explain how you calculate the 70Hz chamber and vent length ? WinISD is capable of 6th order. Is there a substitute way to calculate it or is there anything you can advice on how to calculate? Thx. Matthias 😇
If you go below the resonant frequency of a sub you're going to lose compression doesn't matter if it's in a bandpass box or not. All the band pass box is going to do is allow more high in frequencies it's can't really help for or to go below the resonant frequency because once you go below the resonant frequency you start to lose your air spring that's why the DBS roll off really quick. Just model it and some type of speaker box modeler and you'll clearly see that it won't perform well if if it goes below the resonant frequency
Good to know!
Great video.
Can ya make a video of how to figue out how the cabin in a car effect bass performance?
Great suggestion!
@@BudgetBassHead it would really make a huge difference. It's always been a trail n error kind of thing but that can get expensive n time consuming. Thx
Just one issue. The 70hz slot port needs to share the bottom wall. Having that small chamber below it is going to have unpredictable results. I don’t think the volume will stay consistent due to the restrictive nature of such a narrow space. As you know, 8th orders need to be more accurate than other ported designs. Hope that made sense. 👍👍
And yes the driver needs to have s very high Qms and Qts parameter.
Thanks for the reply. But as mentioned, these are not accurate measurements. This is for display purposes only. And yes, in the case where the 3rd chamber is restricted of adequate volume, this slot port would be replaced preferably by an aero-port or vent.
BudgetBassHead cool. You should go ahead and build it out and give a demo. I’m sure people would want to buy the plans for this beast. ✌️
Kevin, you're unfortunately mis-informed about the Q values that work best in an 8th order BP. The Q values that work best to produce flatter response and deeper low-end are ultra low Qts values. I was given the equations for designing 8th Order BP's by an acquaintance 21 years ago and was then first to post them on the web on Brian Steele's DIYSubwoofers website (circa 1997). Since then I've learned to model them in Akabak, which is even better because you can visualize the cone excursion plot.
There was a latest version of hornresp that promised to be able to simulate bp8.
When I first trialed them I thought the outer chamber needed to be higher.
With BP6 it is relatively easy. Start with a vented box with a driver tuned to a flat response. In a 40hz enclosure aim for an EBP (Fs/Qts) of about 100 to 120. E.g Fs 40hz Qts 0.33. It doesn't matter if it is slightly larger so as to have a 1 or 2 dB peak at tuning.
The front chamber should be about half the size of the back and with twice the tuning give or take. This will give a nice frequency response over the bass range.
With a BP8 the outer chamber will affect the tuning of the inner chambers in ways I do not yet know the maths. In hornresp I have found best results with a very large outer chamber with a tuning halfway between the inner chambers but they are quite fussy with drivers and chamber volume. I have not built and measured one so take this with a pinch of salt. Randomly trying to just build one will usually result in a one note wonder.
Short of a test box with telescopic length changing ports and adding bricks to reduce chamber volumes and an acrylic side that is airtight yet removable I am unsure of how to fine tune the design. If someone has tried and tested plans including a recommended driver that's great.
Unlike vented boxes and sealed which you can usually make an educated estimate of a driver's parameters and come up with an acceptable though perhaps not optimal enclosure.
I know Bose has one of these although am not sure of its specs.
Hornresp will do 8th order BP, but those alignments are probably best for small drivers. 4th and perhaps 6th order series-tuned BP are probably best for car audio duty, if designed with that in mind.
hi man can you make some calculations what is the best box i have two of Martin Wisman Omega Pro 18 and they are in 179l box each tune to 44 i have them for 4 years but i wont them to sound deeper enything below 35 it's almost unhearable
boxes are
71cm*55cm*55cm
port is 10 cm hight and 50 cm widh 30 cm depth
its for home use and i have Martin Wisman ul-t 1260 for them is 400w in ich chanel it have lot of protection and by the way i have jbl Systems active crosover so it is giving a propper signal to subs amp
and if its possible i want the boxes to be as little es possible
THANKS you sooo MUCHHHH
that is the copy of Eminence 18 omega pro Speaker
This is an interesting question. And I'm Not saying that this "couldn't" or "shouldn't" be done. But it would take up so much real estate, that you may be better off with simply building two vented enclosures with a lower frequency tuning. To be honest, I don't think that a dual (18 inch) sub set up for a 4th, 6th or 8th order would be practical for home environments. The enclosure would just be too massive. This is more commonly found in concert settings. This actually highlights one of the downsides to building bandpass enclosures... Very large enclosures. Hopes this helps.
i try to change the port with wood blocks and mathematically lower the tuning port to 25 hz but nothing changed the sound is picking at 40 hz.. definitely i will sell them and by some other lower sounding drivers and build another boxes
Thanks man for the reply
I'm confused because doesn't the lower Hz need a bigger port to get the note out of the box? Your 30 Hz note can't go thru a smaller port can it? Or does it just look that way cause you are not to scale or am I wrong ?
Bandpass if break down the word , only a port eminates sound? if so seventy herz is the"band that allows to pass at a resonance due to the tuning of port..all that passes is the seventy herz band that dro[s very sharplly above and below seventy. thirty and fifty arent even in that range u would hear from it.
So When building a box, each chamber should be tuned to whatever frequencys you want? Or, say for a 4th order, you'd build a sealed boxed to the driver recommendation, and then the ported recommended, bolt them together, and have a 4th order that works as it should? Or is the chamber size dimensions related to certain frequencys?
Find a tuning software you are comfortable with, and find your desired frequency range. The flatter the better.
I listen to a lot of rock with rapid bass I currently have a ported pro box (12" sub) I listen to other types of music on occasion so that's why I got a 12, my question is (because in the current box it struggles to get the rapid bass separated and with power it blurs together) so would a 4th order be a proper box to use for that type of music? Im also trying to save space as well so 8th order would be too big, the sub is a sundown v3.
Keep in mind that anytime your end-goal is accurate, precise, bass; a sealed enclosure outperforms a ported enclosure. You can still get an accurate response with a ported enclosure, but it typically require you to have a system with software to manually adjust phasing and group delay. Hope this helps.
What about port sizes? What size do u need for eac application?
1 vs 2 aero port for one 12 inch 700w rms ; which one is better ? (Pioneer TS-D12D2)
Question: Which one has the flatest frequency response?
Would you please share with me how you were able to put a subwoofer within the design
Thanks for the info.
My subs. Dbxi-15d made by earthquake, have the free resonance(Fs) of 20 hz, that means that they do not need the 8th order boxes?.
The box for this subwoofer was very well calculated, and it is a big box using a big flare port.
I really can enjoy the 20 Hz with subs.
Tell me please your opinion.
Sounds like you got a premium subwoofer. You should be okay with manufacturer's recommended enclosure specs
Need the measurements for a 6th order, to make 3.o cu. Foot box, for a single 12! How do I go about getting them?
I like to put a dayton audio 6.5 inch subwoofer in an 8th order or quasi 6th order bandpass to go with a tectonic BMR full range driver based DIY soundbar so it can strike 20Hz.
Checkout my new Miniature bandpass enclosure, video teaser. I think you may like it.
Nice
Hey sir, your videos are great and u supplied me with a sufficient amount of infos about sound system and boxes that I didn't even know why they call them like that !!😅
But am having a problem with my single pioneer 12" 1400 watt DVC, i had just designed a ported box via winISD which is supposed to be tuned to 23 hz, and i followed the instructions as well as the dimensions given by the application, the box is 70 liters, with a round port of diameter 8 cm and 36 cm long, but the box isn't even playing 29 hz 😫😫😫, so what is problem in your opinion sir ??
Thx in advance sir, love you 😘
Sounds to me like the measurements are correct. However, check to see that your sound source doesn't contain a filter of some sort. Especially home entertainment systems. check any cross overs or amplifier settings.
BudgetBassHead well am using a magnat 420 classic amp and there is no crossover filter, but I noticed that the system is playing 20 hz but at low volume, but once i turn up the volume, i can here nothing, just the sound of my speakers
What about the head unit?
BudgetBassHead well i don't use head unit, i use AUX which is plugged directly to the amp
Sir, I forgot to tell u that my subwoofer box size is greater then the manufacturer recommendations, it is 70 liter, but it is recommended to be 42.5 liters, could this be the problem??
Can you explain port tuning. The differences in runner length. Combined ports output. Examples of music it would be best suited for. Thanks
Stay tuned! Video coming soon.
A vented/ported sub enclosure (very simplified explanation) adds increased output at its tuning frequency. You can actually see the sub almost stop moving but still creating sound at an increased volume than it normally would.
Port Length...
Typically longer equals lower. But, the area of the port plays a huge roll in that equation. The larger the port opening (the area) the longer the port length needs to be to reach the chosen frequency. The smaller the port area, the shorter the length would be required to reach the same frequency.
Less area for your port sounds like a winner and the obvious choice, right?
If only it was that simple....
The problem.... well, the air velocity moves much faster and has a significantly higher amount of turbulence when it exits the port. This combination of speed and turbulence can, and will, create what is called "port noise". It is not a good thing. It can be very audible and sounds pretty awful.
So a larger area of port is needed, which also needs to be longer, which will mean your box will be bigger if you want to maintain the same tuning.
Another factor (and definitely not the last one) is, larger boxes require less length than a small box, that has the same port area, when tuned to the same frequency.
That is about as simplified as i think it can get for just the bare basics.
Of course, theres a lot more variables and they have to be accounted for.
Maybe someone else can correct any inaccuracys i may have presented, but again, there are things that can effect the relationship between an enclosure and the port needed for a desired tuning.
Twinky UnOuWaNtMyCrEaMFiLlInG spot on man! Great explanation
Yo... I have (2) RF Punch Stage 3 P310D's. Dual 2-Ohm or Dual 4-Ohm drivers. 400W RMS/800 Peak. I listen to Heavy Metal exclusively...
Which type of enclosure would be best for me to use in my car or truck?
where do I contact you for a subwoofer design sr.
And here I am with a prefab. Wow. I think I’m missing out.
Seems like bandpass box would have better bass, but i heard lately it's best to go to a T-Line box for bass? What you recommend?
T-lines does have a broader frequency response. However, any advance outside of a sealed enclosure gets larger and larger; with the T-Line being the largest. Size is the compromise.
Badly-designed TLs will be large (i.e. those designed using obsolete and inaccurate rules like "make the cross-section of the line the same as the driver's Sd and the length equal to 1/4 wavelength at the driver's Fs". Better-designed ones are tapered with some driver offset and the size will be a bit bigger than a vented box using the same driver, but it's likely to be smaller than an 8th order BP using the same driver (designed to have a flat passband).
Do you plan to build one of the 8th order encloser.
It is in the works. I got a vid coming soon.
why not drop the green panel closest to the bottom edge, and lower the upper panel to keep the same vent width? It would appear that there is an additional resonant chamber between the lower green wall and the outside of the box wall.
Where can i find a calculator for a 8th other box?
So how do i know how big the port to tune it to 28-30 hz on a regular ported box for a single 15
Win ISD pro Software
How do you come up with the air space and port sizes
so, if i understand this right, i could theoretically have a 28fs driver, tuned at 20hz,40hz, and 80hz, and it should give me the response across the board that i'm seeking (8th order bp.) whereas just a single port tuned to say 25 seemed to not really rattle when hitting 70ish hertz, but was nasty on the low end.
👍
bro i love deep deep bass what enclosure do you recommend me to built for my 15" DC elite
Definitely do a 6th order.
just put a woofer in a seal box and give good power and you can do it all
So you will put more power and get less excursion from port loading, wouldn't you have problems with overheating? Interesting design!
Overheating mostly occurs when your gains are not set properly. If your gains are not set properly, your exceed your (RMS) power rating; which translate into excessive heat. Remember, the power rating of a sub is, in essence, a direct indicator to its thermal rating.
you gain control of the sub in order to be able to apply more power at that specified frequency.
Yeah sure, I was thinking that the less movement the less effcient the cooling becomes
I have two 12 ZVX Skar . How would u make a box for them?
Can I play bass guitar through it?
Now explain how the 3 frequencies are relevant if the last port is the one you hear? Does each chamber's vibration radiate out into the room? Can you split two or more different ports from each chamber to resonate at different frequencies?
as long as the outer Port is large enough to pass the frequency of the inner ports then the inner parts speaking through the outer port
50 Hz speaker perform well above 50Hz so I did not get the reason of adding 70Hz band pass?!
Make the port do the work. Less work for the sub.
Box resonance, not actual driver resonance. Driver will play 120-200 hz with some sizes, but the volume of those sounds is much less than its Fs frequency curve. The box allows certain frequencies to resonate more to gain volume on that specific frequency that the driver couldn't produce on its own.
You HAVE to worry about the frequencies above Fs too friend.
Half an octave above fs is where the voice coil former slams into the magnet and gets deformed.
Proper port tuning and and power matching equals cone control; hence eliminating unloading.
in a 4th order how do i know how big do i make the seal and/or vent chamber
If I was you, I would start with the manufacture's recommended specs. Plug the numbers into your favorite software and adjust from there.
4th order bandpass calculator - With subwoofer box design example
audiojudgement.com/4th-order-bandpass-design/
Sealed chamber 1 cubft..
Ported 3 cubft..
Always 1:3 ratio
Lol told my self try to do with a cheap 8 before going big seconds later your right better quality better material
how do they get named? where did the name come from! where is the 8at?