Hey guys, I've looked all over the web pretty extensively and haven't found my answers yet, so I figure giving the pros a shot'll be worth the effort...
I'm needing to upgrade from my old Adire Rava sub to something that will actually bring down my apartment building, instead of just shaking the crap out of it. I'd like to employ the Tumult, as I really like the Rava and the Adire people, but to get the output that I really want means I can't go sealed. I've never liked ported subs and IB is out of the question (apartment and all) so I'm left with a bandpass design. Here's my problem, I haven't found any solid data on designing a box that will actually provide a near-flat response and avoid the typical one-note bass out of such boxes. Any help would be appreciated, and I will certainly take any other suggestions to heart, my budget is in the area of $700 USD for the sub alone, probably just get a cheap Nady amp or something to power it until I can afford better.
By the way, this will be used with a pair of Wayne J's Eros that I built a few months ago, along with some old Sony ES speakers for multichannel that I desperately need to upgrade. The sub will be used for both music and movies...so I hope this works out. Thanks for your help guys.
I'm needing to upgrade from my old Adire Rava sub to something that will actually bring down my apartment building, instead of just shaking the crap out of it. I'd like to employ the Tumult, as I really like the Rava and the Adire people, but to get the output that I really want means I can't go sealed. I've never liked ported subs and IB is out of the question (apartment and all) so I'm left with a bandpass design. Here's my problem, I haven't found any solid data on designing a box that will actually provide a near-flat response and avoid the typical one-note bass out of such boxes. Any help would be appreciated, and I will certainly take any other suggestions to heart, my budget is in the area of $700 USD for the sub alone, probably just get a cheap Nady amp or something to power it until I can afford better.
By the way, this will be used with a pair of Wayne J's Eros that I built a few months ago, along with some old Sony ES speakers for multichannel that I desperately need to upgrade. The sub will be used for both music and movies...so I hope this works out. Thanks for your help guys.
Forget about it.
The only performance advantage of the bandpass is the ability to trade gain for bandwidth. The more gain, which appears to be what you are ultimately after, the narrower the bandwidth and the more "one note" it becomes.
Whatever it is that you don't like about ported woofers will haunt you in spades with the bandpass.
The only performance advantage of the bandpass is the ability to trade gain for bandwidth. The more gain, which appears to be what you are ultimately after, the narrower the bandwidth and the more "one note" it becomes.
Whatever it is that you don't like about ported woofers will haunt you in spades with the bandpass.
A Tumult is a good idea, but don't forget that dual Ascendant Audio Avalanche 15 will beat the Tumult easily for only 100$ more, or a single Avalanche 15 will come quite close for 200$ less.
Then, if you hate ported boxes, you'll hate even more bandpass boxes. Did you heard well built ported boxes with flat FR and no vent noise?
Then, if you hate ported boxes, you'll hate even more bandpass boxes. Did you heard well built ported boxes with flat FR and no vent noise?
Best the Tumult? I don't know. Can you give me a link to this driver so I can check this claim out? I didn't know Ascendant Audio made anything big enough to out-do the Tumult driver.
Here's the link...
http://www.ascendantaudio.com/Avalanche 15.htm
I said a pair of Avalanche 15 would be better than a single Tumult for only 100$ more because :
Fs is lower (15.6 Hz vs 19 Hz)
Le is lower (2.4 mH vs 4.2 mH)
Efficiency is slightly better (87.5 dB vs 87.1 dB)
Xmax is slightly less for the Avalanche at 27mm versus 34mm
If you model them, the size of the box is very slightly larger for the Avalanche, but it's 200$ cheaper.
So a pair of these would beat the displacement of the Tumult, with 8.08 liters versus 5.09 liters linear displacement, for only 100$ more. That's about 59% more displacement with only being 20% more expensive than a single Tumult.
http://www.ascendantaudio.com/Avalanche 15.htm
I said a pair of Avalanche 15 would be better than a single Tumult for only 100$ more because :
Fs is lower (15.6 Hz vs 19 Hz)
Le is lower (2.4 mH vs 4.2 mH)
Efficiency is slightly better (87.5 dB vs 87.1 dB)
Xmax is slightly less for the Avalanche at 27mm versus 34mm
If you model them, the size of the box is very slightly larger for the Avalanche, but it's 200$ cheaper.
So a pair of these would beat the displacement of the Tumult, with 8.08 liters versus 5.09 liters linear displacement, for only 100$ more. That's about 59% more displacement with only being 20% more expensive than a single Tumult.
simon5 said:
You make a good argument... and wouldn't two of those sound totally better too? Less thermal compression, potential for cancellation of room modes, stereo low-bass, or one box with push-push for force cancellation...
So basically a pair of avalanches in a (properly built) ported box would be a better use of my money then? Basically the only reason I don't care for ported boxes is because a number of friends have built some before, and they never seem to sound right to me. Always too bassy and the port itself is noisy.
I'm a tumult owner myself.... and I suppose two avalanche 15's wouldnt have been a bad way to go. But the Tumult is a very nice driver, and I'm not a bit dissatisfied.
I'm running my tumult in 6cubic feet tuned to 10hz and honestly you probably wouldnt tell a big difference between that and a sealed enclosure. Except in the infrasonics of course
I'm running my tumult in 6cubic feet tuned to 10hz and honestly you probably wouldnt tell a big difference between that and a sealed enclosure. Except in the infrasonics of course
danvan said:
Yes, a well built ported box would be a better use of your money especially if you want to bring the building down. I must say that you have a very comprehensive neighborhood...
If well built, you'll have zero port noise.
If well built, we include a theorical room gain curve in the design, so the subwoofer have a shallow rolloff outdoors, so indoors it's not too bassy, it's flat down to as low as you want to.
They will sound right because they will be tuned low, so group delay is out of the picture also.
If you're looking at SPL at 30 Hz and more, you could build 2-3 Tempest Bass Horn for insane SPL, but not much response under 25 Hz.
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Joined 2002
What was it that you dont like about ported boxes what it the port noise ? Maybe it was the box you had that did this if the port is to close to the rear chamber wall it will make lots of noise or if the port is to small it will do the same. I had a 10" sub in a band pass box with 3 x 3" ports at 9" long and i also had a sealed and ported 15" sub the truth the 10" bandpass KILLED it in spl and quality of sound..
Jason
Jason
Jason, I don't mind ported subs, since I do love bass... it's just that I haven't heard very many that have been designed/made well enough that port noise isn't noticeable. Any design ideas? I'd like to keep it as small as possible (it's not really an issue, but should I move someday...or some woman starts caring about decor, etc.) Or for that matter, would two separate ported avalanches provide any benefits?
Well, these subs are working well in vented enclosures of around 5 cu.ft
So you get two Avalanche 5 cu.ft box internal net volume or a Tumult 5 cu.ft box internal net volume.
I would tune these boxes around 18 Hz. So you would need two 4" ports per Avalanche box to use the full power without noise.
So you get two Avalanche 5 cu.ft box internal net volume or a Tumult 5 cu.ft box internal net volume.
I would tune these boxes around 18 Hz. So you would need two 4" ports per Avalanche box to use the full power without noise.
Yeh - use huge portsdanvan said:
My Tempest sub uses two 10cm pieces of fall pipe, and of course, you can never hear any port noise. If it's played too loud it can be localised, and that's using a 24db/oct x-over at 50hz! So don't underestimate distortion! Go overkill as far as you can I say! 😎
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Joined 2002
Soon when i run into some money ill be buying 2 10" subs and porting them and running them with mono amplifiers one per side of the room But for me i love ported boxes there more efficient and i like there lower roll off..
For high excursion 15"s I really recommend using a 6" flared port, instead of 2-4" ports. Using the 6" flares basically guarantees no issues with port compression.
An externally hosted image should be here but it was not working when we last tested it.
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ThomasW said:
Id like to build this exact thing but smaller box and a 10" a set of these in my house would be retarded.. I looked at your site on how you built that. That is some super work there. good job.. i bet it is loud too. : O )
I think the Ascendant Audio Atlas subs are worth looking at. They need less power than their avalanch subs and have the lowest inductance of any subs I've seen - 0.96 mH, which means superior transient response. I see them as bang for buck AND SQ champions, the only downside is they need fairly large boxes, much like Shiva and Tempest. One possibility is to use sealed boxes with the Atlas 15 with a LT. Say use 4 of them and you could power them with a bang for buck PA amp like the Behringer EP2500 with 1.2 kw x 2 into 2 ohm loads.
I'm using that amp with a pair of (soon to be) vented 60L AE speakers AV12s. They need all the power it can put out since they are less efficient subs which work in a smaller box.
It's not that difficult to get a vented box without port noise problems. Some tips:
* 4" circular vent as a minimum for a 12" driver with high excursion
* use large flares, the bigger the radius the better
* use a rumble filter, makes a big difference
* design for < 34m/s vent velocity
* tune a little lower than you might have otherwise
If you achieve all this you should not have a problem at all.
My subs are in test boxes and I'm using a 4" vent in which I haven't yet used flares and vent noise has never been a problem, the only exception being when playing test tones deliberately trying to get turbulence, and then I can say that flares make a big difference.
18mm radius flare helps
36mm is quite a bit better
72mm is also quite a bit better again and what I intend to use
One thing I found is that a 120mm vent was not an improvement. The reason is that I had to tune higher to get it to a length that could fit in the box. The result was I got the same vent velocity with a vent with a larger volume which is more difficult to accomodate. Hence a 100mm vent tuned lower was easier to implement.
I'm using that amp with a pair of (soon to be) vented 60L AE speakers AV12s. They need all the power it can put out since they are less efficient subs which work in a smaller box.
It's not that difficult to get a vented box without port noise problems. Some tips:
* 4" circular vent as a minimum for a 12" driver with high excursion
* use large flares, the bigger the radius the better
* use a rumble filter, makes a big difference
* design for < 34m/s vent velocity
* tune a little lower than you might have otherwise
If you achieve all this you should not have a problem at all.
My subs are in test boxes and I'm using a 4" vent in which I haven't yet used flares and vent noise has never been a problem, the only exception being when playing test tones deliberately trying to get turbulence, and then I can say that flares make a big difference.
18mm radius flare helps
36mm is quite a bit better
72mm is also quite a bit better again and what I intend to use
One thing I found is that a 120mm vent was not an improvement. The reason is that I had to tune higher to get it to a length that could fit in the box. The result was I got the same vent velocity with a vent with a larger volume which is more difficult to accomodate. Hence a 100mm vent tuned lower was easier to implement.
All these huge excursion CHEAP drivers have fine specs,but when the kilowatts are being applied and those woofers are flying about, theyl be distortion,and the tumult has a MEASURED THD unlike the others. And more distortion means you can localise it. In the end it comes down to using twice the volume of boxes for two cheepes to achieve the same SPL as one goodie.
Id be more interested in their spectral contamination[two tone etc] and steady state THD
[400 or 800litre horn soon]
edit:
Re: bass reflex
Note that people do a maximally flat alignment[modeled in 2pi space] So the moment you place this woofer in a corner its louder and boomier ![energising LF room modes more easily than sealed simply because it has more output]
Design the subwoofer with an overdamped alignment[impossible
with some] and better sound should result.
Oh come on paul,the subwoofers will have 70hz or lower lowpass wont it?
Id be more interested in their spectral contamination[two tone etc] and steady state THD
my 2226 hits 12m/s peak with the amplifier I have,The pressure at the port is quite nice
[400 or 800litre horn soon]edit:
Build one.Itl be loud enough. Infact, dont build one because the FR has a bump in the midbass[seems to need adjustment imao,prolly reduce rear chamber abit]
Re: bass reflex
Note that people do a maximally flat alignment[modeled in 2pi space] So the moment you place this woofer in a corner its louder and boomier ![energising LF room modes more easily than sealed simply because it has more output]
Design the subwoofer with an overdamped alignment[impossible
with some] and better sound should result.
Attachments
One Note Bass - Taken from JL Audio;
As the size of the ported chamber increases, the bandwidth decreases. So, the more efficient we make the system, the smaller the passband will be. If the system is made too efficient (outrageously large front chamber), we'll wind up with "one-note" bass so typical of a myriad of mis-tuned bandpass enclosures on the market today. On the other hand, as the front chamber volume increases, the better the transient response of the system will be, and this is good.
The whole story;
http://www.jlaudio.com/tutorials/bandpass/index.html
I agree partially with you about ported boxes. They just don't sound and feel right. Although they're might be a box out there that does sound good. I just haven't come across one.
I've built a bandpass with a flat response from 35 - 85 hz.
However, fiddleing around with the port length I liked a little hump at 55 hz. about 3 db. I then tried a 5 db hump and liked it more. Increasing the hump started to reproduce that one note bass.
I used Win Isd and Unibox to model it. The Unibox graph did not reproduce the response I wanted, so I punched in the WinIsd numbers in Unibox and got the response - 35 - 85 hz.
I stuck a plate amp on it to further kill a port resonance around 350 hz.
I haven't stopped there. My next experiment is with a dual chambered ported box;
http://www.diysubwoofers.org/prt/dual_chamber.htm
http://planeta.terra.com.br/educacao/claudionegro/english/
Then on to a Tapered Transmission Line with 2 - 8" woofers.
I have to find out what really smooth bass sounds like.
As the size of the ported chamber increases, the bandwidth decreases. So, the more efficient we make the system, the smaller the passband will be. If the system is made too efficient (outrageously large front chamber), we'll wind up with "one-note" bass so typical of a myriad of mis-tuned bandpass enclosures on the market today. On the other hand, as the front chamber volume increases, the better the transient response of the system will be, and this is good.
The whole story;
http://www.jlaudio.com/tutorials/bandpass/index.html
I agree partially with you about ported boxes. They just don't sound and feel right. Although they're might be a box out there that does sound good. I just haven't come across one.
I've built a bandpass with a flat response from 35 - 85 hz.
However, fiddleing around with the port length I liked a little hump at 55 hz. about 3 db. I then tried a 5 db hump and liked it more. Increasing the hump started to reproduce that one note bass.
I used Win Isd and Unibox to model it. The Unibox graph did not reproduce the response I wanted, so I punched in the WinIsd numbers in Unibox and got the response - 35 - 85 hz.
I stuck a plate amp on it to further kill a port resonance around 350 hz.
I haven't stopped there. My next experiment is with a dual chambered ported box;
http://www.diysubwoofers.org/prt/dual_chamber.htm
http://planeta.terra.com.br/educacao/claudionegro/english/
Then on to a Tapered Transmission Line with 2 - 8" woofers.
I have to find out what really smooth bass sounds like.
What's your idea of cheap? I don't think that's appropriate to the drivers we are talking about here.
You miss a significant point here - transient response. I'm not talking about high end rolloff related to inductance. Adire have a technical article which shows from a theoretical and with measurements that lower inductance means a better transient response. Which is interesting since the Tumult has a high inductance.
THD has been proven to be irrelevant in predicting sound quality:
http://www.gedlee.com./distortion_perception.htm
The drivers I'm talking about are based on the same technology as the Tumult, and I would expect similar low distortion performance and BL and suspension linearity. However, they are cheaper as they have less xmax and hence lower inductance. They also need less power. From a cost and performance point of view it's preferable to get a given output target with less power and more SD. This is what I'm suggesting as an alternative.
Consider this - a pair of Atlas 15s could move as much air as a single Tumult for about 2/3 of the driver cost. It would also cost quite a bit less to power it.
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