Bass & Subwoofer

[boxerfan88]

MUSINGS: The need for full-range sound (likely with subwoofers) in audiophile systems. [And Ojas New Ageism?]

A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.

archimago.blogspot.com

 

[boxerfan88]

If you want to hear what 20 Hz content sounds like you need over 100 dB SPL with less than ~10% distortion and less than ~30 ms group delay @20 Hz.

Hmm …

 

[boxerfan88]

Interesting snippets…

I think marketing by the sub companies makes it seems like getting quality 20 Hz (or below) response is "easy" and can be magically accomplished with small enclosures, high xmax, and lots of DSP. Unfortunately, physics says otherwise, and the mechanical demands of producing quality LF sound are very difficult and require large enclosures, large drivers, and large amplifiers.

If you try to get by with small enclosures and use DSP to extend LF extension, you end up with high distortion and especially high group delay. To me it seems like the companies are exploiting a "rule of thumb" that "1 cycle" of group delay is "acceptable".

While it is a reasonable for most frequencies when you start getting into the real low frequencies like 20 Hz then it is 50 ms and many of these sub are higher than that and are approaching 100 ms. Not only does this smear transients but it also make integration with the mains very difficult. It is also usually accompanied by a large increase in distortion with many of the smaller subs on the list having between 50% and 100% THD. The other "rule of thumb" for group delay is 20 ms or less which in my experience it about right.

If you look at the subs that perform well at or below 20 Hz (high SPL, low distortion, low group delay) they are gigantic.

 

[boxerfan88]