Hi
There is a type of subwoofers whose utter neglect by audiophiles I am unable to comprehend: The Infinite Baffle Subwoofers. Simply stated. An IB use a part of the house adjacent to the listening room as a HUGE sealed box with multiple low frequency drivers. Could be the crawling space under the floor.. A basement, another room or the attic.
This type of subwoofer easily offers performance NO commercial subwofer can even (or could ever) dream of... Things like amplifers-like low distortion < 1% THD, 120 dB at 20 Hz. flat down to single digits ( <10 Hz) with up to 110 dB at the listening position, very low cost and total invisibility are routine with IBs.. Yet. You hardly , ever hear mention of these in audiophile circles.
They are derided as "shaking" the house (which they can) and bass noise, too difficult to make, etc..
I have often written about IBs.. I have implemented IB for friends, could not in my house because the listening room offered no place to IB except the outside which I was going to consider at one point but ... they are easy to make, easier than one would think and produce all by themselves a level of bass that is uncanny both in power, refinement and unusually distortion.. yet.
You mention "IB subwoofer" to most audiophiles and it either draw a blank or a snicker... What an interesting breed we seem to be
@Raul
Smoothness of response is a very important aspect of sound reproduction. The auditory system routinely accept high level of distortion. It would be a shock for many to know that we easily accept 50 % of THD in the bass...most woofers distort seriously in the low bass anyway and that includes numerous commercial woofers of distinction and great price. Smoothness of response means that the listening room-subwoofer system responds in a linear fashion to change in frequency. Peaks and valleys that are so common in bass reproduction impart that artificiality to the sound... So it is important to seek smoothness if not necessarily flatness in bass reproduction. It can be shown rather easily that the vast majority of people prefer a smooth but rising bass curve.. in other words a response skewed toward the lowest frequencies sloping down in the highest frequencies... So while it is good to reduce IMD and that usually involves addressing it at the level of drivers and the simplest way to do that is to use more subwoofers.. since the sheer number afford individual drivers to work less, the sum produces less distortion anyway so.. you have the best of both worlds.. Smoothness of response and reduced distortion level both audibly and measurable.. One reason I love this solution and before we go into the debate about "slow" woofers and "fast" mains... a nonsense by the way, let it be said that thanks to Home Theater and the Car enthusiasts, yes, them we have a plethora of excellent low frequency drivers on the market .