How Much Subwoofer Is Enough?

[nathan]

Thanks! Will read.

That's a good powerpoint, but if you want the real technical details of the research, AES (or Welti) have made the core research paper from 2006 free to download:

Download Now

 

[andyc56]

That's a good powerpoint, but if you want the real technical details of the research, the AES (or Welti) had made the core research paper from 2006 free:

Download Now

Here's another, slightly earlier one from Todd Welti that can be downloaded. In some ways this one is more interesting than the final one, as there's some discussion of some techniques that he considered but did not use in the final implementation.

Edit: I inadvertently posted a link earlier that was behind a paywall. This one is not restricted.

 

[nathan]

Here's another, slightly earlier one from Todd Welti that can be downloaded. In some ways this one is more interesting than the final one, as there's some discussion of some techniques that he considered but did not use in the final implementation.

Thanks. Too bad it’s behind a paywall.

 

[nathan]

Back on the topic of how much bass is enough, CEDIA and the CTA have taken the THX stuff a few steps further with their RP22 document (https://cedia.org/advocacy/standards-best-practices/immersive-audio-design-excellence/).

It's worth noting that this is PEAK output capability, NOT an expectation of sustained playback level.

(column headers are in the next image...)

It’s just one of 21 factors in the standard for audio reproduction, which are intended as a set of objective measures for how a system performs or is designed to perform.

You'll quickly note that column 3, a LEVEL 3 system, is what used to be called "cinema reference level" in terms of output, etc., with things like "average playback level of 85db with headroom up to 105db" in the main speakers, and so on.

This makes a lot of sense for a system that is used for movies since most movies are mixed to this standard. Technically, many mastering suites used for home video mixes are apparently mixing for six db lower than theatrical reference these days, so what you get on your UHD disk may or may not expect traditional reference level settings.

Music is another matter. But it is not likely mixed with MORE dynamic range than movies, so having a system capable to reference level cinema reproduction usually means it can handle any musical dynamics/output requirements.

 

[HalSF]

Todd Welti published the research about 20 years ago. Using multiple subwoofers can reduce (sometimes eliminate) room modes in the subwoofer range.

But MOST importantly multiple subwoofers can create consistent seat to seat subwoofer response, which means you can EQ for one seat and solve response in the other seats, at the same time with the same EQ choices -- something that is impossible in domestic rooms with a single subwoofer.

(Note that I didn’t mention anything about increased output. Welti did measure that as well but multiple subs is typically an inefficient way to increase output.)

E-library page - AES

AES E-Library ← Back to search

aes2.org

Many thanks, more useful reading to do. I’m beginning to reconsider my paranoid theory that logrolling for multiple subs is a plot by Big Audio.

 

[tetragrammaton]

When you play at max output from your preamp into your amps and then speakers, in most cases that would be around 100ish dB at the listening position unless you have high output speakers, and you have zero audible compression in bass, all the whilst having a +20dB bass boost, then you have enough subwoofer

PS. This is tongue in cheek, but I think having the capability of 120dB output throughout 20-80Hz is very cool. I don't have that, but I have plans for achieving that

 

[StigErik]

I have twenty-four 10’’ subwoofers in my Double Bass Array. Limited by available amp power, I can’t do more than 115 dB between 20 and 80 Hz. But I can do it with less than 1% THD….

 

[xrqp]

I think you are saying that 2 x 21" sounds better than the previous 2 x 15". Others have also said that improving the subs made the mains sound better, and I think you are saying that too.

I wonder if there is a way to measure that? Or can we just use the common measurements of power, distortion, and frequency response?

 

[jhaider]

And why the contribution of my single SVS subwoofer, which already sounds great to me, is inadequate and begging for enhancement.

If you’re happy, you’re happy.

Play your system and walk around the room. You’ll hear significant variations in the bass. Some people (myself included) want as even bass across the room as possible. IME that means 3-5 subs. Fortunately with that many they needn’t be that large.

 

[nathan]

I think you are saying that 2 x 21" sounds better than the previous 2 x 15". Others have also said that improving the subs made the mains sound better, and I think you are saying that too.

I wonder if there is a way to measure that? Or can we just use the common measurements of power, distortion, and frequency response?

First you would want to measure a well calibrated system in a double blind test and confirm that it is actually preferred by listeners. Most reports of improvements are from sighted tests, with different positions for the subs, different levels for the subs, and often different EQ runs with an auto setup system. Just changing the output level by 3db will make one sub sound perceptually better than another. Sitting in a peak can make one sub sound more powerful than another.

I'm not saying that extra output is useless but that there are very few reports showing the advantage of more output when operating within the designed limits of a system. The big difference is when operating in a larger space, or working on reaching down to lower frequencies. In those cases, measurements like output level, range, and distortion tend to correlate most closely with perceptions of quality. Hence the CEA 2010 system of measurements. It's not perfect, but it's remarkably predictive.

 

[theREALdotnet]

I have twenty-four 10’’ subwoofers in my Double Bass Array.

Hm, 24 seems unlucky (mathematically). I think you should shoot for 29 or 31. Or remove one.

 

[theREALdotnet]

I reckon using more subwoofers will allow for more even bass reproduction across the room, and flatter response at any point in space. It will also reduce distortions, the more woofers the better. The downside is that you will likely need a software-based approach to analysing and equalising the sub responses.

 

[gnarly]

I have twenty-four 10’’ subwoofers in my Double Bass Array. Limited by available amp power, I can’t do more than 115 dB between 20 and 80 Hz. But I can do it with less than 1% THD….

Sweet !!! What driver(s)? What amp(s)?

 

[StigErik]

Drivers: Seas L26ROY
Amps: ICEpower 2000as2 and 1200as2

One might think the ICEpower 2000as2 is a 2x2000W amp, but it's not....

From the datasheet:

 

[mj30250]

Whelp, I did a thing.

Two additional TV2112Ms were added to the setup. I mean, someone has to put their hearing, marriage, and home's structural integrity at risk for the purposes of ultimately answering the topic, right? Well, maybe not...but I did it anyway.

Here is a nice loud sweep after completing an Audyssey run, along with the distortion measured. This setup is now fully capable of cleanly exceeding my personal limits...so perhaps, the question is indeed answered. Ask me again in another few months to be sure.

 

[Oddball]

View attachment 393091

Whelp, I did a thing.

Two additional TV2112Ms were added to the setup. I mean, someone has to put their hearing, marriage, and home's structural integrity at risk for the purposes of ultimately answering the topic, right? Well, maybe not...but I did it anyway.

Here is a nice loud sweep after completing an Audyssey run, along with the distortion measured. This setup is now fully capable of cleanly exceeding my personal limits...so perhaps, the question is indeed answered. Ask me again in another few months to be sure.

View attachment 393092

View attachment 393093

Looks amazing but make sure it keeps the structure of the building intact Also I try to keep exposure to high volumes to 2 hours a day max.

 

[Fredygump]

View attachment 393091

Whelp, I did a thing.

Two additional TV2112Ms were added to the setup. I mean, someone has to put their hearing, marriage, and home's structural integrity at risk for the purposes of ultimately answering the topic, right? Well, maybe not...but I did it anyway.

Here is a nice loud sweep after completing an Audyssey run, along with the distortion measured. This setup is now fully capable of cleanly exceeding my personal limits...so perhaps, the question is indeed answered. Ask me again in another few months to be sure.

View attachment 393092

View attachment 393093

Now you will have to keep an RTA running while you watch movies so you can monitor how much sub-20hz content you are getting.

I'm curious about how much subsonic content there is in different formats? I'd like to see some type of measurements, not anecdotes of room shaking experience. I would be slightly tempted to build another sub for sub 20hz if I knew there was something to be gained by doing so. But for the time being, ~17hz and above is working pretty well for me.

 

[EJ3]

I’d love to learn about the history of the two-subwoofers prescription in home audio. It’s absolutely triumphed as the default recommendation and dominant configuration discussion topic in subwoofer discourse. When did it emerge as an accepted and preferred thing? Is there a decisive objective case for the sonic superiority of doubling up, and an objective case for the inferiority of a single subwoofer in music systems?

I’m *never* going to add a second subwoofer in my 11’ x 17’ listening room, to disclose my bias.

I've been doing it since 1990 (2 customized by me old Radio Shack (the larger black ones) CAB's ported & tuned to 29 Hz. The speakers are Pioneer car audio competition 12" dual 4 OHM voice coils configured to one 4 OHM load each, with a FR of 20 Hz-80 Hz. With an NAD 2200 bridged mono pumping out up to 1600 watts on each sub (about 1/2 of what they are rated for).
(word of mouth made me do it [no, it wasn't the Devil])!

 

[Flaesh]

PSA

Happy panter: