Great information as I consider the smallest 'user-feasible' jamming 12" cab with the bits I have already got. The tuning port sizing was particularly helpful. Thanks so much 👍
I'm glad you found it useful, I used this to tune my favorite little cab, and I'm giving with it several times a week this summer, works like a little champ 😀
Jeez, I have two sets of 15s and 12s that have never sounded good (bought empty and installed what I had). The 15s especially have very little low end but I don't want to get rid of them because they are super solid boxes. Thanks a bunch for this!
It depends if they have a ridiculously high Q and you need a box the size of a wardrobe and a home theatre style tuning and run out of travel at under 50 watts.
Very nice, I’ve been on a journey through pro-audio, guitar, bass guitar, and home theatre and car audio speaker cabinets. I’ve built my share over the last few years and understood fairly well the science behind T/S , efficiency, port tuning and all that… I had pictured in my head that better efficiency would allow the same power to push the driver harder , but it turns out that greater efficiency means LESS cone movement per given power. Now I can use this technique with my ported buulds to see if my efficiency is going up or down. I knew there had to be a practical hands on way to measure it without pure math/software
Hi Nick! I agree with your hypothesis, and hope this does turn out to be useful for you! The standard Thiele Small design concept is tried-and-true, but I think there are often variations or unanticipated elements that can alter the anticipated outcome, so a real-world test like this can be useful for verifying and making adjustments, if needed. Thank you for watching, and for your input!
@@steelcrossing5324 thank you for making the video! Yes, you’re right about unintended or unintentional effects on performance, I tried using PVC pipe for my last car subwoofer box and it performed SO well, compared to my slot port boxes, probably because of the precision of the geometry in a perfect cylinder of PVC vs my imperfect slots. But yeah, loved the video, keep up the good work my man!
To obtain a sweep of vibrations, it is enough to have a light source (for example, a projector or a high-quality mirror spotlight and a small piece of Mylar mirror film, which is glued to the protective cap. By observing the shape and size of the spot, you can obtain an optical sweep of the vibrations of the speaker cone. Such an “oscilloscope” is very visual at low frequencies. But for small bass cabinets, I would prefer a passive radiator design. This will reduce the thickness of the cabinet walls and, due to the smaller pressure difference inside and outside, reduce the load on the walls. The area of the passive radiator can be 4-6 times the size of the speaker cone, and you will benefit from loudness articulation and damping. Good luck in the design and friendly greetings from Russia.
I think the idea of making a reflective scope to illustrate the cone movement is brilliant! Thank you so much, and my greetings to you as well. The concept of a passive radiator is intriguing, I have seen them in home speakers but not bass guitar cabinets. It sounds interesting and could be very useful. All around the earth, we share the same moment in time and the same love of music. I'm grateful for your comment!
@@BajaKoala In one monograph I saw efficiency graphs obtained from area horn emitters. This is the dry physics of air constants. So, the explanation from this is that if we make a passive radiator with a larger area than the speaker, we get a damping effect at lower and lower frequencies without adding additional mass, and vice versa. So, we need a very light passive radiator of a larger area in order not to lower the frequency to the required one due to an additional weight, but to use active elastic resistance and thereby reduce this frequency. We see the same thing with large groups of bass guitar drivers.
You could probably get by with a 5 string bass and a cab tuned higher than 31 cycles if you have a high pass filter and the second harmonic should still thunder through nicely even if you are tuned in the upper 30s, especially if you're not going for a big subby dub reggae sound or you have PA support, in which case it's better to turn off the low low bass in your cab and send a DI. You can lengthen a slot port with extra boards if you want to lower a tuning without choking off too much area.
That's pretty cool Mr. Jorin. I'm building separate woofer cabinets for my 3-way HiFi speakers. Although I'm using WinISP for port sizing, you're trick will be used too, because I'm a crappy 5-string bassist & will interface with my HiFi /PA to practice along with the music. Very nice check on the design. Keep up the FUNK! 🔈🔉🔊
Thanks for your comment, I hope the info helps a bit! Getting down to 31 Hz for the five string (assuming your low note is a B) might require shrinking the port size, but if you do that too much you sacrifice the efficiency benefit of the port. I'm sure you'll figure out what you like the best, and that's what matters 🎶
This assumes that the speaker is actually generating 'some' significant amount of 41Hz signal, and not just 'synthesizing it through and overabundance of the harmonics that come of it; which is a common method used by many speaker manufacturers to 'flesh' out the bass of cabinets/speakers that are physically incapable of generating any real bass. They simply design a 'bump' in frequency response around 80Hz (a much easier and cheaper thing to do than actually addressing the bass deficiency), a note that most small cabinet/speaker combination actually 'can' generate. I'd like to see the same test done at 82Hz. If the dislocation of the grains of rice has the same amplitude, you know you weren't actually witnessing the results of a 41Hz signal. A sweep test would be very revealing to, as would a test that varies the length of the Helmholtz resonator tube. Thanks for this video.
If you did the same test at 82 Hz and had a similar response, would you really know that the cabinet was incapable of generating sound at 41 Hz, or would you simply know that it appeared to have the same resonant effect at that frequency? I think you might have only learned what was actually observed. Otherwise, by extension, you might be assuming that if you had a similar result at 328 Hz, that no sound at any of the lower frequencies was actually being created. My ears would refute that hypothesis, even without measuring equipment. Ultimately, I was not intending to provide a perfect analysis tool, but one that could help create a useful cabinet that would sound good for the intended purpose and prevent hyperextension of the speaker cone. Desire for simplicity of the process, and having a useful cabinet for little investment, might yield a different final product than a more in-depth process with sweep testing and use of a Helmholtz resonator tube. Perhaps you could make a video where those tools and processes are explained in such a way that the average bass player could implement them. Thanks for your input!
yes, great info...i have a sonic 15 cabinet, with unknown speaker inside ive used with a 210 combo amp for years..also bought a 15 neo speaker, but have not replaced it yet...kinda like the sonic cabinet, but it always sounded eh..ok, but not great..
There is a good chance that covering part of the vent slot on that Sonic cabinet will dramatically improve sound and efficiency, I'd love to hear what your results are when you give it a try!
This is an extremely useful tutorial. Thank you very much. Is there a "down & dirty" way to determine a port size for a cabinet that has no existing port? I have a non-ported 15" cabinet that is probably not as deep as it should be. I'm thinking that it would be more efficient with a port, but am not sure how to determine the best/proper port size. Please advise if able. Thank you!
I can't guarantee the accuracy, but this interactive tool looks good to me and would be really easy to use. The good news is that if you make a slot too big, you can always cover it a bit to tune, using the process in my video. As you will note on this calculator, the depth of the vent matters just like the size, so rather than just cutting a slot you will want to plan to put in a board to direct the air around it - that's an important element in making it all work together: boomspeaker.com/subwoofer-port-calculator/
Thanks Bob. Sounds like a quick and practical method. I have a round port on my cabinet with internal cylinder of few inches. As I know, both affect, the radius and the length of the cylinder. If bloking the port with your hand does not do much the challenge is to decide if perhaps a larger radius or a different cylinder length will give a better result. Do you have an idea how to decide? I guess that it might be necessary to check the cabinet resonant frequency (with the rice) and try to lower it below 41Hz, which will probably be challenging in a 12" speaker...
The process of calculating ports is somewhat complex, as are almost any acoustical design processes regarding the production of sound waves using electromechanical components. My video was just intended as a fast and dirty tool for people who changed drivers in a vented box they already had, but there are many calculators available if you want to improve or create an acoustic design concept. If you go to this page, click "Loudspeaker" and then "Port/Vent Calculator", there is a tool that you may find useful: www.mh-audio.nl/Calculator.html
Yes, that would probably work about the same and would be easier for most people than getting the sine wave generator going. If you do that, I'd suggest making sure the tone control is turned all the way down so you are using the closest thing available to a simple sine wave. If you have two pickups to choose from, use the one near the neck as it typically has more fundamental note and less harmonics. I didn't think to mention that as an alternative, I guess because I found it easy to do what's in the video and it is somewhat more reliable of an indicator. But go for it, and please let me know how that works for you!
Good question! Very low, or the little items you put in the speaker cone will bounce around like crazy even at the optimal aperture. So you can do it quietly, probably even while people are sleeping.
The first couple of minutes are pretty shaky looking, sorry about that, it settles down quite a bit when the actual demonstration begins... too much coffee maybe?😁
I really didn't pay much attention to frequencies in the octaves above the fundamental that I was trying to optimize for. I figured that was the hardest (and therefore most critical) band to tune for, and any other anomalies I notice on stage I just compensate for with eq on the amp. This is one reason that sound engineers prefer to get signal direct from the bass or right after your effect pedals, so any eq you add down the line does not affect the house sound.
Thanks for the question. The cables do not need to be the same length. The signal passes through cables at almost the speed of light, so in order to introduce a meaningful delay (at even the highest audible frequency of 20,000 cycles per second) the cable length would have to be very long indeed. I didn't calculate it, but it's thousands of feet. Happy music making!
Nope. I have been on boats and I didn't die, but I live in a house on the land a couple blocks from Lake Michigan. If I lived 1/4 mile east, it would be a boat. I made this video in the basement 👍
You can check for efficiency at other frequencies using the same process, but as the frequency rises, the cone will not move as far in either direction. This technique is really intended to focus on maximizing efficiency at one frequency, typically the lowest note you want the cabinet to work at.
Great information as I consider the smallest 'user-feasible' jamming 12" cab with the bits I have already got. The tuning port sizing was particularly helpful. Thanks so much 👍
Best information I have found about tuning ports. Thanks
I'm glad you found it helpful!
Excellent video. I was tuning a cab by ear but intend to go back and use this technique. Thank you.
I'm glad you found it useful, I used this to tune my favorite little cab, and I'm giving with it several times a week this summer, works like a little champ 😀
Jeez, I have two sets of 15s and 12s that have never sounded good (bought empty and installed what I had). The 15s especially have very little low end but I don't want to get rid of them because they are super solid boxes.
Thanks a bunch for this!
Hopefully this well help them sound much better at those low frequencies, thanks for your comment and please let me know if you have any questions. :)
It depends if they have a ridiculously high Q and you need a box the size of a wardrobe and a home theatre style tuning and run out of travel at under 50 watts.
@@TimpBizkit I don't even remember what they are.. EVs but not sure of the model
Thank you soo much. It was very helpful information.
I'm glad you found it helpful! 😊
Very nice, I’ve been on a journey through pro-audio, guitar, bass guitar, and home theatre and car audio speaker cabinets. I’ve built my share over the last few years and understood fairly well the science behind T/S , efficiency, port tuning and all that…
I had pictured in my head that better efficiency would allow the same power to push the driver harder , but it turns out that greater efficiency means LESS cone movement per given power. Now I can use this technique with my ported buulds to see if my efficiency is going up or down. I knew there had to be a practical hands on way to measure it without pure math/software
Hi Nick! I agree with your hypothesis, and hope this does turn out to be useful for you! The standard Thiele Small design concept is tried-and-true, but I think there are often variations or unanticipated elements that can alter the anticipated outcome, so a real-world test like this can be useful for verifying and making adjustments, if needed. Thank you for watching, and for your input!
@@steelcrossing5324 thank you for making the video!
Yes, you’re right about unintended or unintentional effects on performance, I tried using PVC pipe for my last car subwoofer box and it performed SO well, compared to my slot port boxes, probably because of the precision of the geometry in a perfect cylinder of PVC vs my imperfect slots.
But yeah, loved the video, keep up the good work my man!
Very helpful! Thank you!
I'm glad you found it useful!
Very informing
Thanks
Thanks for watching!
To obtain a sweep of vibrations, it is enough to have a light source (for example, a projector or a high-quality mirror spotlight and a small piece of Mylar mirror film, which is glued to the protective cap. By observing the shape and size of the spot, you can obtain an optical sweep of the vibrations of the speaker cone. Such an “oscilloscope” is very visual at low frequencies.
But for small bass cabinets, I would prefer a passive radiator design. This will reduce the thickness of the cabinet walls and, due to the smaller pressure difference inside and outside, reduce the load on the walls.
The area of the passive radiator can be 4-6 times the size of the speaker cone, and you will benefit from loudness articulation and damping.
Good luck in the design and friendly greetings from Russia.
I think the idea of making a reflective scope to illustrate the cone movement is brilliant! Thank you so much, and my greetings to you as well. The concept of a passive radiator is intriguing, I have seen them in home speakers but not bass guitar cabinets. It sounds interesting and could be very useful. All around the earth, we share the same moment in time and the same love of music. I'm grateful for your comment!
@@BajaKoala In one monograph I saw efficiency graphs obtained from area horn emitters. This is the dry physics of air constants. So, the explanation from this is that if we make a passive radiator with a larger area than the speaker, we get a damping effect at lower and lower frequencies without adding additional mass, and vice versa. So, we need a very light passive radiator of a larger area in order not to lower the frequency to the required one due to an additional weight, but to use active elastic resistance and thereby reduce this frequency. We see the same thing with large groups of bass guitar drivers.
Nice idea!
Very cool. I've just ordered some sonic style 10's for studio subs, and I'll try this when I set them up. Stay warm. Karl
You could probably get by with a 5 string bass and a cab tuned higher than 31 cycles if you have a high pass filter and the second harmonic should still thunder through nicely even if you are tuned in the upper 30s, especially if you're not going for a big subby dub reggae sound or you have PA support, in which case it's better to turn off the low low bass in your cab and send a DI.
You can lengthen a slot port with extra boards if you want to lower a tuning without choking off too much area.
Thanks, your comments are insightful and make good sense!
That's pretty cool Mr. Jorin. I'm building separate woofer cabinets for my 3-way HiFi speakers. Although I'm using WinISP for port sizing, you're trick will be used too, because I'm a crappy 5-string bassist & will interface with my HiFi /PA to practice along with the music. Very nice check on the design. Keep up the FUNK! 🔈🔉🔊
Thanks for your comment, I hope the info helps a bit! Getting down to 31 Hz for the five string (assuming your low note is a B) might require shrinking the port size, but if you do that too much you sacrifice the efficiency benefit of the port. I'm sure you'll figure out what you like the best, and that's what matters 🎶
@@BajaKoala Thanks
keen
This assumes that the speaker is actually generating 'some' significant amount of 41Hz signal, and not just 'synthesizing it through and overabundance of the harmonics that come of it; which is a common method used by many speaker manufacturers to 'flesh' out the bass of cabinets/speakers that are physically incapable of generating any real bass. They simply design a 'bump' in frequency response around 80Hz (a much easier and cheaper thing to do than actually addressing the bass deficiency), a note that most small cabinet/speaker combination actually 'can' generate. I'd like to see the same test done at 82Hz. If the dislocation of the grains of rice has the same amplitude, you know you weren't actually witnessing the results of a 41Hz signal. A sweep test would be very revealing to, as would a test that varies the length of the Helmholtz resonator tube. Thanks for this video.
If you did the same test at 82 Hz and had a similar response, would you really know that the cabinet was incapable of generating sound at 41 Hz, or would you simply know that it appeared to have the same resonant effect at that frequency? I think you might have only learned what was actually observed. Otherwise, by extension, you might be assuming that if you had a similar result at 328 Hz, that no sound at any of the lower frequencies was actually being created. My ears would refute that hypothesis, even without measuring equipment. Ultimately, I was not intending to provide a perfect analysis tool, but one that could help create a useful cabinet that would sound good for the intended purpose and prevent hyperextension of the speaker cone. Desire for simplicity of the process, and having a useful cabinet for little investment, might yield a different final product than a more in-depth process with sweep testing and use of a Helmholtz resonator tube. Perhaps you could make a video where those tools and processes are explained in such a way that the average bass player could implement them. Thanks for your input!
Charlie Farquharson lives!!
yes, great info...i have a sonic 15 cabinet, with unknown speaker inside ive used with a 210 combo amp for years..also bought a 15 neo speaker, but have not replaced it yet...kinda like the sonic cabinet, but it always sounded eh..ok, but not great..
There is a good chance that covering part of the vent slot on that Sonic cabinet will dramatically improve sound and efficiency, I'd love to hear what your results are when you give it a try!
This is an extremely useful tutorial. Thank you very much. Is there a "down & dirty" way to determine a port size for a cabinet that has no existing port? I have a non-ported 15" cabinet that is probably not as deep as it should be. I'm thinking that it would be more efficient with a port, but am not sure how to determine the best/proper port size. Please advise if able. Thank you!
I can't guarantee the accuracy, but this interactive tool looks good to me and would be really easy to use. The good news is that if you make a slot too big, you can always cover it a bit to tune, using the process in my video. As you will note on this calculator, the depth of the vent matters just like the size, so rather than just cutting a slot you will want to plan to put in a board to direct the air around it - that's an important element in making it all work together:
boomspeaker.com/subwoofer-port-calculator/
Thanks Bob. Sounds like a quick and practical method.
I have a round port on my cabinet
with internal cylinder of few inches.
As I know, both affect, the radius and the length of the cylinder.
If bloking the port with your hand does not do much the challenge is to decide if perhaps a larger radius or a different cylinder length will give a better result.
Do you have an idea how to decide?
I guess that it might be necessary to check the cabinet resonant frequency (with the rice) and try to lower it below 41Hz, which will probably be challenging in a 12" speaker...
The process of calculating ports is somewhat complex, as are almost any acoustical design processes regarding the production of sound waves using electromechanical components. My video was just intended as a fast and dirty tool for people who changed drivers in a vented box they already had, but there are many calculators available if you want to improve or create an acoustic design concept. If you go to this page, click "Loudspeaker" and then "Port/Vent Calculator", there is a tool that you may find useful: www.mh-audio.nl/Calculator.html
great video! just wondering, could you do this test with the E string of the bass?
Yes, that would probably work about the same and would be easier for most people than getting the sine wave generator going. If you do that, I'd suggest making sure the tone control is turned all the way down so you are using the closest thing available to a simple sine wave. If you have two pickups to choose from, use the one near the neck as it typically has more fundamental note and less harmonics. I didn't think to mention that as an alternative, I guess because I found it easy to do what's in the video and it is somewhat more reliable of an indicator. But go for it, and please let me know how that works for you!
At what volume should this test be run at? At a low volume or at normal volume?
Good question! Very low, or the little items you put in the speaker cone will bounce around like crazy even at the optimal aperture. So you can do it quietly, probably even while people are sleeping.
The first couple of minutes are pretty shaky looking, sorry about that, it settles down quite a bit when the actual demonstration begins... too much coffee maybe?😁
I drank a bunch of coffee before I watched it, and it all evens out LoL
Needed some Glenlivet 12 for that 12" speaker lol
@@jtromsness It's important to stay lubricated, and keep the stresses in check.
so what freq. should the rice start dancing? My 12 inch cab starts rice vibrating at about 95hz
I really didn't pay much attention to frequencies in the octaves above the fundamental that I was trying to optimize for. I figured that was the hardest (and therefore most critical) band to tune for, and any other anomalies I notice on stage I just compensate for with eq on the amp. This is one reason that sound engineers prefer to get signal direct from the bass or right after your effect pedals, so any eq you add down the line does not affect the house sound.
a hpf works nicely
Do pos and neg wires in cabs need to be exactly the same length ?
Thanks for the question. The cables do not need to be the same length. The signal passes through cables at almost the speed of light, so in order to introduce a meaningful delay (at even the highest audible frequency of 20,000 cycles per second) the cable length would have to be very long indeed. I didn't calculate it, but it's thousands of feet. Happy music making!
Do you live on a boat?
Nope. I have been on boats and I didn't die, but I live in a house on the land a couple blocks from Lake Michigan. If I lived 1/4 mile east, it would be a boat.
I made this video in the basement 👍
what about 42 to 2k hz
You can check for efficiency at other frequencies using the same process, but as the frequency rises, the cone will not move as far in either direction. This technique is really intended to focus on maximizing efficiency at one frequency, typically the lowest note you want the cabinet to work at.
@@montiac6796 most excellent
@@kaybhee6 Thanks!