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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
shadorne's avatar
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shadorne
7,477 posts
 
@soundsrealaudio 

So you obviously could not find any (not one) high end professional studio facility using 6 inch woofers for their main monitors!!!

I hope you learned something. 6 inch woofers being fast is a myth. As far as bass is concerned 6 inch woofers are woefully inadequate except in near field setups where a compromise in bass response, accuracy and dynamic range is acceptable for convenience and cost benefits.
jhills
615 posts
 
The great myth about subs is - while many audiophiles expect their subs to be fast - there is nothing fast or quick about 20 HZ or even 30 HZ. While there are good and bad subs "there is no such thing as a fast sub". The job and the only job of a good sub should be to faithfully produce the bottom octave/octaves of your musical presentation. A good sub should always be filtered to operate only below 50 or 60 HZ, otherwise you're expecting it/them to do the job your high dollar stereo speakers (regardless if they are panels or boxes) should be doing. While I'll not argue the importance of the quality of driver/drivers, cabinet, electronics and design, needed to make a good sub, the size of drivers and cabinet and the amount of power needed to drive it to a level that meets your expectations, is completely dependent on the amount of space you're asking it to fill. Because frequencies below 60 HZ become non directional and interact differently with the room and to the listener than higher, more directional, frequencies. Even in a live performance the lower notes of a string base, base guitar, or organ sound displaced and more felt than heard. It is more critical to match your sub/subs and power to the room than to your speakers.
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soundsrealaudio
756 posts
 
bdp24

I love that moniker.

You seem to reenforce the belief that subs are not in good control, if not they wouldn't need a servo. 
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bdp24
9,806 posts
 

The Rythmik Direct Servo Feedback Subwoofer system is a very sophisticated design (patented, for what that’s worth)---many subs are nothing more than a woofer and an amplifier in a box---that accomplishes a number of goals for it’s designer, PHD Brian Ding. For instance, all loudspeaker driver voice coils heat up with use, slightly altering the driver’s electrical characteristics. The Rythmik DSF compensates for changing woofer coil temperature, keeping the driver’s electrical characteristics consistent. All woofers, in fact all drivers, would benefit from that.

All drivers have a rise time (when hit with a signal), and a return to "rest" capability (when the signal stops), ideally not over-shooting the "at rest" position of the voice coil within the magnetic field of the driver’s motor when attempting to do so. Servo-feedback systems, found in the woofer columns of the Infinity IRS and RS-1b (which I use to own), have long been known for affording superior inter-transient silence, another term for non-overshoot driver performance. There are a few ways to achieve high performance in that regard, servo-feedback being a cost-efficient means of doing so. The Rythmik subs excel at that performance characteristic. Just as the Eminent Technology LFT driver has been described as "quiet" (very low "noise"), the Rythmik subs have a very high degree of inter-transient silence. They are unusually good at blending with planar loudspeakers, sounding "leaner" (no bloat) than most other subwoofers.

The Rythmik sub designed in collaboration with GR Research’s Danny Richie, the only OB/Dipole sub in the world featuring servo-feedback woofers, is State-Of-The-Art. A pair of those subs (usable up to 300Hz), combined with the Eminent Technology TRW-17 Rotary Subwoofer (designed to be used for reproducing 20Hz and below!), greatly exceeds the capabilities of any other subwoofer in existence. Not cheap (the TRW-17 especially), but cheaper than the woofer section of the $100,000 and above loudspeakers available to the well-heeled.

Rythmik owner/designer Brian Ding has a very detained explanation of his designs on the company website, for anyone interested enough to read it all. Warning---it’s quite technical!

wolf_garcia
6,696 posts
 
I think there is a lot of pretentious blather around this subject…any good main speakers in a normal room (furniture, books, things people simply own) should sound great if pointed at you properly, which requires some moving of the things away from walls, toward walls, wider apart, closer…until YOU think it's sounding good. Then get a sub or two (I use a pair of "previously owned" "Q Series" RELs), move 'em around until they seem to sound good, and relax. Done. If you think you think you need DSP then add that, although I don't like it. A friend uses the same main speakers I have (Silverline Prelude "D'Appolito" arrayed small woofer things) with 2 RELs like mine, and the DSP simply seems to strangle the sound somehow, so I remain without EQ of any sort, other than sub level tweaking here and there.
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