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

@bdp24   

I believe Meyer do this also (a microphone in front of the woofer).

The alternative to correcting for errors is to eliminate them by using a single layer large 4" short length voice coil in extremely tight tolerance massive long magnetic gap - very expensive woofers indeed!

@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.

@soundsrealaudio      

Can you find any multi million dollar recording studio using 6" toy size woofers for bass on their main monitors?

You can't because these are professional facilities that do things correctly without following some weird urban myth about woofer speed (probably started by an ignorant hobbyist reviewer or a monitor (toy) sized speaker manufacturer). 

Large 15" woofers don’t have to do higher frequencies and are never required to operate as fast as a tweeter! Duh. Face Palm. However they do reproduce bass frequencies orders of magnitude better than small 6 or 8" woofers. Those who would deny this are just drinking maketing BS. Clearly some people are unaware of the physics of a large surface area vs a small one and the Xmax (linear) limitations of voice coil travel.

Slow bass or poor PRAT is a combination of poor timing alignment, poor frequency response balance between mids tweeter and woofer, as well as resonant Q tuning and port tuning of the box. A dip in the mid range will reduce bass punch. High Q systems resonate and make the bass "hum" or sound "blurred" rather than "punch". Exceeding Xmax or a long voice coil in a short magnetic gap means non linear response, excessive compression from heat and a dull boomy smeared bass. Dull boomy smeared bass is what most 6 or 8 inch woofers with cheap 1 inch voice coils do! A 15" woofer with a 3 or 4" voice coil is a much better design, as far as audio fidelity is concerned at LOW frequencies. Of course you can’t expect a 15 inch woofer to even begin to do the mid range like a 6 inch can. 6 inch is a monitor or toy size when it comes to bass and 15" is professional.

You simply can NOT find a reputable studio with large main monitors that have 6 inch woofers and there is a good reason you can’t! So please stop repeating the marketing BS about fast small toy sized woofers!

+1 Audiokinesis and Erik

15" and larger woofers are key to good bass. You can’t beat the advantage of a large surface area except with multiple woofers. Multiple woofers are harder to drive so not a good choice. Basically....

One 15" woofer is equivalent to
Two 12" woofers
Three 9" woofers
Six 6" woofers

The amp controls the woofer and the air suspension suppresses the resonance of the woofer if properly designed. A woofer designed to work without a box may have a stiffer suspension but these are an exception rather than the norm.

@kost_amojan. 
 
Well it should be easy for you to show me a link to a Stereophile or other measurement plot of a JM Labs high end speaker that does not have a bass boost, bass bump or hump?

You should be looking for a flat response that gently rolls off in the bass with no increase in response below 120 Hz at all. I feel sure you can find this as you are extremely confident.

ULF Bass is the most difficult to reproduce accurately. 99% of what is available is reflex extended resonant bass - B&W, Wilson, JM Labs and all the major audiophile brands do it. Most boutique brands do it too. You can easily identify this by the hump in the bass on a frequency plot and the one note bass sound of 99% of speakers.

Clean bass needs a Q of 0.7 or less and two 15 inch woofers in most domestic settings. (4 x 12" woofers will be equivalently capable.) I rarely see this kind of setup on Audiogon so I don’t think many people are even aware of the issues raised by Erik.

Sticking a good subwoofer with 99% of these reflex extended speakers is just not going to be able to correct the one note resonance. Hardly anyone builds speakers without the characteristic one note bass resonance as a low Q box sounds anemic in bass especially at low volumes and is therefire unlikely to sell in shop floor demos against competitors.