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Why is good, deep bass so difficult? - Myths and their Busters

This is a theme that goes round and round and round on Audiogon. While looking for good sources, I found a consultancy (Acoustic Frontiers) offering a book and links:

http://www.acousticfrontiers.com/guide-to-bass-optimization/?utm_source=CTA

Interestingly: AF is in Fairfax, CA, home to Fritz Speakers. I really have to go visit Fairfax!

And a link to two great articles over at sound and vision:

https://www.soundandvision.com/content/schroeder-frequency-show-and-tell-part-1
https://www.soundandvision.com/content/schroeder-frequency-show-and-tell-part-2

Every audiophile who is dissatisfied with the bass in their room should read these free resources.

Let me state unequivocally, deep bass is difficult for the average consumer. Most audiophiles are better off with bass limited speakers, or satellite/subwoofer systems. The former limits the danger you can get into. The latter has the most chance of success IF PROPERLY IMPLEMENTED.

The idea that large drivers/subs are slow is a complete and utter myth. Same for bass reflex. The issue is not the speed of the drivers. The issue is usually that the deeper a speaker goes the more it excites room modes, which the audiophile is then loathe to address.

Anyway, please read away. I look forward to reading comments.
erik_squires
erik_squires OP
16,156 posts
 
I have seen a couple of takes on the fan as a woofer idea.

Just FYI, as Dr. Leach was fond of saying, 0 Hz isn’t a sound, it is wind.

Another was kind of a corkscrew in a tube. Seems to be long disontinued, the Phoenix Gold Cyclone by BNIB.

Another way to use a rotating motor is converting the rotation to linear travel with a flapper, like the Devialet.

Neither method really resolves room mode issues and trades motor strength for effective surface area. As a signal drops an octave, displacement must increase by a factor of 10 for any given driver, so 1mm at 40 Hz becomes 10mm at 20 Hz, and so on.

Fans, assuming they can spin fast enough, eliminate the excursion issue. No idea about distortion figures. I can say that with a Hsu VTF 15 I can get monstrous output in room at 16 Hz, so not really a problem I need to solve.
erik_squires OP
16,156 posts
 
Did a little searching on data-Bass.com

At least on paper, the rotary woofers don't seem to do all that great compared to far less expensive solutions. Seem to be just as output and distortion limited as their coned counterparts, or at least close enough to make the $12k price tag questionable.

Best,

E
gdhal's avatar
gdhal
1,641 posts
 
@erik_squires

I haven’t read the articles in your initial post as you state "every audiophile who is dissatisfied with the bass in their room should read these free resources’ and I am not dissatisfied.

Give a serious listen to a pair of Golden Ear Triton Reference and I think you would conclude that good, deep bass is *not* so difficult.
erik_squires OP
16,156 posts
 
gdhal,

We are not going to agree there, at all.

Best,

E
auxinput
2,920 posts
 

I went through this bass problem and solution this year. I did investigate some. The DBA double-bass array did seem to solve a lot of the problems, but I just could not implement that many drivers in my room. Based on my experiences, there are actually a couple things that are required for good deep bass:

- Power supply in source/preamp (and even amp) components.

- Acoustics / standing waves problems.

The power supply capability in source/DAC will absolutely contribute to deep/tight/strong bass. The dac/preamp may sound good, but unless it has a massively sized power supply, it will just not be able to push those very large waveforms. I have seen discrete Class A preamps that the manufacturer has just tossed a couple 3200uf caps in and called it a day. A good example is Krell KAV-280p and Bryston BDA-2. Both have undersized power supplies, in my opinion. You really need something like 20,000uf for Class A circuits. The Oppo BDP-105 has a decent power supply (2 x 6800uf), but remember it is using conventional op amps (not Class A). This is not the whole story however. Avoid gold-plated or silver-plated components if you want deep/tight/strong bass. This is where rhodium plated elements can be your friend (power cords, interconnects, even fuses when applied conservatively and properly).

The other problem is, of course, problems with standing waves in small rooms. I went through a bass tuning exercise this year and I actually now have 14 (counted them) 2’ x 4’ bass panels. Six Owens 2" 703FRK, four 2" Roxul Rockboard 80, two GIK Monster Bass Traps with Flexrange Limiter, and two limp-mass bass panels tuned to 63 hz. All are covered with Guilford fabric except for the limp mass. I plan to add two more limp-bass bass panels tuned to 50Hz.

The bass is significantly (night and day) deeper and stronger that it was before at my listening position. I also no longer feel like my ears are compressed in a vacuum (due to over pressure at some frequencies). It is a enormously better situation. I made all bass panels myself except for the GIK. I think I spent less than $1200 total.

Acoustics is very important here. However, if the deep/tight bass is not there from the source/preamp, you are not going to get it by adding bass treatments.

I will say that the GIK monster bass trap with the FlexRange limiter is an exceptional product if you are looking for a broad-band bass trap. The limiter panel increases bass absorption without sucking the life out of the mid/high frequencies. Positioning is important as this may work better in some areas.

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