size of subwoofer drivers vs. size of main speaker drivers

ddk

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May 18, 2013
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Those are the subs in the one wall. There are multiple sets.


I don't have a picture of that handy.


80 Hz.


It is the real room. Everything is normally hidden behind fabric though. We have a set of LED lights that when you turn them, you can peer into what is behind them. Here is a side-by-side view, with and without back light:


Thanks Amir, it clears a few things for me. Beautiful HT room!

david
 

Rodney Gold

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Jan 29, 2014
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Here are some pics of my "swarm" , 3 subs in corners , 1 against the wall...

Going to hook it all up later today... the Yamahas are beautifully made subs .. 40lbs a pop .. and they were not expensive - $1.5k in total

If it works well , I will spring for better subs... or maybe not :)












 

ACHiPo

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Feb 22, 2015
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Here are some pics of my "swarm" , 3 subs in corners , 1 against the wall...

Going to hook it all up later today... the Yamahas are beautifully made subs .. 40lbs a pop .. and they were not expensive - $1.5k in total

If it works well , I will spring for better subs... or maybe not :)
I definitely think you're onto something, and suspect you'll be happy with the 4 little Yamahas based on others' reports on the swarm approach. You may find, however, that the corners give you more room gain than you want (I did). I highly recommend the "subwoofer crawl"--putting the first sub in the listening position and finding the best bass response, placing the 1st sub there, etc. then optimizing the DSP for each sub with REW. I found that by changing crossover frequency, phase, damping factor, and volume I could significantly flatten the bass response and I just have 2 subs (still planning on adding at least one more, this time a 15", or maybe a Yamaha based on your results ;)). I think it was Geddes that suggests best results with different sub sizes, damping factors, etc. to help randomize thus flatten the modes.
 
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Mark Seaton

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I definitely think you're onto something, and suspect you'll be happy with the 4 little Yamahas based on others' reports on the swarm approach. You may find, however, that the corners give you more room gain than you want (I did). I highly recommend the "subwoofer crawl"--putting the first sub in the listening position and finding the best bass response, placing the 1st sub there, etc. then optimizing the DSP for each sub with REW. I found that by changing crossover frequency, damping factor, and volume I could significantly flatten the bass response and I just have 2 subs (still planning on adding at least one more, this time a 15", or maybe a Yamaha based on your results ;)). I think it was Geddes that suggests best results with different sub sizes, damping factors, etc. to help randomize thus flatten the modes.

There is some balance between "throwing enough random subs around a room and it will eventually smooth out" and carefully searching for useful and complimentary locations. I much prefer the latter. Keith Yates & the Synthesis system provide a means to do this through modeling, with the caveat that the model needs to correlate to your room. In newly constructed spaces with regular, continuous and rigid outer boundaries (outer shell, not cosmetic inner wall), this can work very well. When a room already exists and you have a practical set of possible subwoofer locations, an empirical approach of measuring the frequency response of a known subwoofer from each location can quickly reveal a useful combination. Creating the best blend over the seating area empirically requires some discipline in collecting and labeling a useful range of measurements, but the results can be quite good. I see that I hadn't posted the measurements from this system I installed last summer. I'll add those to the thread and you can see what I achieved with nothing more than a delay adjustment, and then how Dirac did when it attacked the problem. The result confirmed for me that for the time being, we're still best manually blending multiple subwoofers and leaving the room correction systems to smooth the response/ringing as a system, although Dirac does have some newer technology which hopes to creatively tackle the multiple subwoofer problem as well, but it's not yet available as a product.
 

Goliath

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Nov 21, 2012
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Interested to hear the results. Would be great to see how smooth your response is with all four subwoofers. Can you perhaps show us some measurements?
 

Rodney Gold

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Jan 29, 2014
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I have reduced the in room variance in bass from peaks/nulls of up to +- 15db to much much less than that . In the order of 3-5db .. plain to hear if you walk about the room

I have 2 subs corner loaded and the other 2 at varied heights in the room agianst walls , the varied heights has to a large measure taken out the floor to ceiling modes.

I use DIRAC with a target curve to do the house curve and any other correction below around 2-300hz and considering the curve at listening position is a preference thing , do the final tuning by ear

Suffice it to say that the bass is awesome , tight , articulate , stygianly deep but there are other benefits too , the soundstage opens up and you feel more "immersed" in the music with the 4 small subs.. you can actually sit anywhere in the room and experience the same bass. The massive corners build up is no longer there.

I was considering replacing them with some really serious subs , but there is no real benefit in doing so imho as the 4 "cheapies" do the job and are nowhere near their limits.
 

LL21

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Just did a trade-in of my old DD18 for the new DD18+. The old one needed a repair (2nd time in several years)...so it seemed like a timely opportunity with the Distributor.

Within 30 min setup, we are now just breaking in the sub, but we've got a graph from 15hz to almost 200hz which is within 3db+/-...thanks to the setup software, microphone, etc...a very nice start.

Compared with the old DD18, the foundation of deep bass in the music is more rock solid, more effortless. The old DD18 by comparison delivered deep bass whacks (in comparison) with almost a 'shiftiness' in that it almost could not 'hold the note' as steady as the new DD18+. The notes dont feel like they are going anywhere with the later sub.

As for the OP regarding Sub drivers and their Main speakers drivers, i really cannot say. But with only one corner/spot available for a sub (ie, no way to do multi-subs), i can say this 18" sub works remarkably well with the 12" and 15" drivers of the Wilson. I have 0 technical knowledge here, so it could be a complete fluke...but if it is...i'll take it! ;)
 

Ron Resnick

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+/-3dB from 15hz to almost 200hz is all you could possibly hope for! Congratulations!
 

LL21

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+/-3dB from 15hz to almost 200hz is all you could possibly hope for! Congratulations!

Thanks, Ron. Transformers 2 was fun tonite as well as more critical music listening. ;)
 

LL21

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+/-3dB from 15hz to almost 200hz is all you could possibly hope for! Congratulations!

Almost 30 hours of break-in later, and the new DD18+ sub is improving nicely. But i hear that not just thru the deep bass, but thru lower mid/upper bass registers as well...the overall presentation is more definitive, more coherent-seeming, more effortless. I suspect i may have to hold off making any EQ adjustments while this process goes on...i recall Wilson saying their 15" cones took about 100 hours or so.

Still...fun to have the full presentation from 20khz to (sub) 20hz back again after my old Velodyne DD18 gave out after nearly 8 years of faithful service.
 

Ron Resnick

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That is great progress!

How is the Velodyne connected? Are you sending a full-range signal to the subwoofer and using the built-in low pass filter to bring the subwoofer up underneath the Wilsons?
 

LL21

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That is great progress!

How is the Velodyne connected? Are you sending a full-range signal to the subwoofer and using the built-in low pass filter to bring the subwoofer up underneath the Wilsons?

Thanks, Ron. Yes, full range Pre-amp signal and then using all the digital eq, filters with Distributor to bring the sub in under the full-range Wilsons.
 

Aluminous Audio

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Aug 21, 2015
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multiple subwoofers

In response to RonR's question about design considerations by manufacturers, at my company (I own Aluminous Audio) we adhere to the multiple subwoofer system concept. Many reasons for that with one extremely good one...smooth, musical sounding bass throughout the room. When set up with 4 subwoofers the soundstage gains a large degree of depth and clarity.
 

Ron Resnick

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In response to RonR's question about design considerations by manufacturers, at my company (I own Aluminous Audio) we adhere to the multiple subwoofer system concept. Many reasons for that with one extremely good one...smooth, musical sounding bass throughout the room. When set up with 4 subwoofers the soundstage gains a large degree of depth and clarity.

Thank you for responding! Am I correct in deducing that, in theory, if a four tower speaker system had woofer columns with four 15" drivers in each vertical column then you would prefer those eight 15" woofers to be distributed around the room as discrete modules (rather than as four 15" drivers stacked in each tower)?
 

Rodney Gold

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There is not much improvement after 4 sources of distributed bass .. but towers are in a sense distributed bass due to the vertical distribution .. kinda like stacking subs..
I initially tried my subs with 2 of them elevated in height. I have now gone with 4 x SVS SB13 ultras but they too heavy for me to hoist.
 

Aluminous Audio

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Aug 21, 2015
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Thank you for responding! Am I correct in deducing that, in theory, if a four tower speaker system had woofer columns with four 15" drivers in each vertical column then you would prefer those eight 15" woofers to be distributed around the room as discrete modules (rather than as four 15" drivers stacked in each tower)?

You are welcome RonR. It is a priviledge to share experience and knowledge with individuals seeking state of the art sound. You are correct in deducing that the eight 15" woofers will perform better as discrete modules. With the low freqency loudspeakers in separate enclosures, they can be placed for nearly perfect time alignment with the main loudspeakers. When the time alignment of low frequency sound is matched to the full range left and right loudspeakers, the overall sound becomes more coherent and musicality of the sound is increased across the board. The listeners brain interprets the low frequency sound as indistinguishable from the overall soundfield. This is often what people hear with subwoofer(s) capable of fast transient response, assuming they are placed correctly in the listening room. Careful setup is crucial to avoid increasing the peaks of the rooms inherent nodes. The sound will be better from top to bottom, not just more heft to the low end.

Along with time alignment to to the mains, the subwoofer modules prevent vibration induced distortion going to the mains.
 

Duke LeJeune

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Careful setup is crucial to avoid increasing the peaks of the rooms inherent nodes.

Unless your subs are all in or near the same location, which clearly is not what you're recommending, placement is fairly forgiving with multisub systems. With multiple subs distributed, whether symmetrically or asymmetrically, it is impossible for any two of them to have identical patterns of room-induced peaks, and thus their summed response will inevitably be smoother than any one of the subs all by itself.
 
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Rodney Gold

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I can turn all my subs off instantly , my speakers have 4 x 11" bass units with a 50mm excursion , so can do low bass as well as any of the subs...
The effect is amazing when using the subs , the whole soundstage expands and you have a much more immersive experieince , the low bass becomes much tighter with more articulation and impact and imaging improves.
The downside.....

 

Mark Seaton

WBF Technical Expert (Speaker & Acoustics)
May 21, 2010
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Unless your subs are all in or near the same location, which clearly is not what you're recommending, placement is fairly forgiving with multisub systems. With multiple subs distributed, whether symmetrically or asymmetrically, it is impossible for any two of them to have identical patterns of room-induced peaks, and thus their summed response will inevitably be smoother than any one of the subs all by itself.

While the approach is sound, I have to throw some water on the notion of this being a magic bullet, especially without a lot of qualifying conditions. I've set up and measured many rooms where simply dropping 3-6 subwoofers in a room is anything but a plug-n-play great result. There are plenty of cases where subwoofers can cause broad cancellations unless some delay, phase or crossover adjustments are made between them.

Here's one example measured in a real room of front and rear subwoofers with 4 subwoofer locations across the front wall and a 6' stack in the rear corner. Each of the 6 units are producing the same output in this example, with no EQ applied. The bottom, red curve is the plug-n-pray result. Stepping higher through the curves at 45Hz (cursor) we see the result of simply adding 3, 7, 8, 10 and 12 msec of delay to the rear column of subwoofers. The differences here were hugely and easily audible with the maximum delay resulting in a 27dB gain in observed output at the listening position:
thebland-subs+delay-mainsea.jpg

As is always the case with subwoofers in real rooms, without a microphone, you're guessing. In very well known acoustic conditions, it might step up to educated guessing, but there are many more variables that many overlook or are unaware of.
 

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