Will I benefit from a subwoofer with 20Hz speakers?

My point, and I made it after my head got hot, is that rather than demand I do more work, others should instead follow the discussion and contribute their own findings.

Honestly, I am super curious about seeing data from audiophiles comparing their speaker’s published spec and in-room response. I would learn a lot from that.

Very little benefit, IMHO, would come from me recording my system, and honestly, I don’t have a lot of time and energy for this. The more others contribute their experience the better the elephant will look.

I am by no means anti-sub.  I love subwoofers, but consumers should be clear-eyed about where their system is starting from and what problems or benefits they hope to achieve.

I have _never_ seen anyone regret analyzing and treating their room before adding a sub, but I have seen some decide not to sub.

Do most audiophiles not understand that the published speaker specs are in an anechoic lab unless otherwise stated?

 What you say is true, however if you were use a low cutoff filter at 40Hz. With most music I doubt if you could hear the difference. A subsonic filter cuts in about 40 Hz and I could never tell the difference apart from stopping the excess movement of the bass speaker.

@bishop148 

A filter has a cutoff frequency that is defined as the -3dB point. You will get phase shift above that frequency; up to 10X the frequency if a 6dB/octave filter is used, less if a 12dB filter is used but you get more of a 'bump' just above the cutoff. The ear perceives the former as a loss of impact.

I played bass in the orchestra for decades and now play keyboards in a band; I like electronia and there are plenty of ambient recordings that have significant material below 40Hz (roughly low E on a bass). Having a number of speakers laying around, I've two sets where the cutoff is about that frequency and I most definitely miss the bottom end using them without subs.

Yuo tell us acoustics is simple. Put two small swarm subs in the room and your ears won’t hear any peaks or dips. Well, to me it isn’t.

@gosta 

I didn't say acoustics is simple. What I did say is that setting up a set of Swarms is quite easy. I experienced immediate improvement. Also, I only use 2 Swarm subs because my main speakers are flat to 20Hz. I got away with 2 subs but most people would need 4. I can cycle the subwoofer amp on and off and the difference is obvious. 

@erik_squires The data sure seems to suggest a standing wave. There is a dip of about 8dB and then a peak. If this is at the listening chair as described it should be outside the room boundary effect. A bit depends on the room of course. But since we have that dip, no amount of power will correct it since its cause by cancellation. That's why you break up the standing wave with a distributed bass array. Then if the room still has issues they won't be hard to correct.

why I keep saying measurement is important, and we may be adding subs for the wrong reasons. Let the OP clean up his bass first, and then decide, based on his own needs and values if a sub is worth the trouble.

Everything I have to say about the Distributed Bass Array I wrote about here, and it is as true today as when I wrote it: