What are the smallest speakers that are clean and flat down to 20hz?

Barefoot MM27 with two 10 inch woofers, two 5.25" midrange and a tweeter in a compact 20.5 x 9.5 x 15.5 inches cabinet are the closet thing to what the OP claims to want. It is like a bookshelf two way but having two JL fathom 110 built into each speaker - that is four 10 inch woofers!!!

These will easily outperform Ohm Walsh and any other speaker suggested here in terms of low end response, dynamic range and overall clean extreme high SPL - they are without doubt the smallest truly full range speakers on the market.

There are some nice speaker suggestions above and Totem, for example, make great speakers, as do Ohm, but in this rather stringent requirement of smallest and full range there is a clear leader that makes other speakers that "sound big" look like kids toys.

Shadorne Barefoot is one I am not familiar with. Those seem to add the powered subs, in fact 4 separate powered bass drivers per speaker in a small package indeed. hard to argue with that. Thanks for identifying those.

Seemingly a smaller package but would they outperform the OHM 5015? Those go for about 10K. Totally different beasts otherwise but with 4 powered bass driver per speaker could be.   They do show -3db down at 30hz in teh specs though which would seem to indicate the size is limiting them to some extent in regards to low end extension if not low end dynamics otherwise.

Here is link to info on OHM 5015:

http://ohmspeaker.com/speakers/beta/

Specs say +/- 3 db at 16hz.

I have OHM F5s which is same cabinet, same main driver (12"), minus built in 15" powered sub and is ported not sealed.

Also smaller similar Walsh 2s with similar driver but 8".

F5 can be adjusted to room size but is overkill for smaller rooms only.

As far as 'the room will have some influence certainly'.  I completely disagree with Ralph on this because he is seriously underestimating the effect  the room has on bass response and has chosen to ignore the mountain of scientific data compiled on this subject

I think actually we're on the same page. But Mapman is talking about 20Hz response and so am I. That's a bit different than **perception** of bass, which is very much affected by the room (for example I have a room resonance at 26Hz in my room, which tends to reinforce bass impact, but its at 26Hz no 20Hz. I tend to be very literal it that helps...). IOW the room isn't going to change the actual frequency response of the speaker, although it will affect to a large extent the **perception** of bass coming from the speaker.

Duke LeJeurne of Audiokinesis makes an excellent subwoofer system he calls 'The Swarm'. It is a set of multiple subs that can be distributed so you don't have problems with bass in some parts of the room (like the side wall) and not in others (like the listening chair).

As a general rule of thumb I usually regard the room as half of the overall system sound.

If the SPL is 3 dB down at 20 Hz then you will hear 20 Hz as half as loud as any frequency that is measured as 0 dB. If 20 Hz was found to be - 6 dB it would be 1/4 as loud as a frequency at 0 dB.

Actually in the above case being down 3 db it would take double the amplifier power to make up the difference but the ear would not hear the -3db as half as loud. If the speaker were 6 db down then that tends to sound closer to 'half as loud' and would take 4x amplifier power to correct.

geoffkait: If the SPL is 3 dB down at 20 Hz then you will hear 20 Hz as half as loud as any frequency that is measured as 0 dB. If 20 Hz was found to be - 6 dB it would be 1/4 as loud as a frequency at 0 dB.

to which atmasphere replied,

"Actually in the above case being down 3 db it would take double the amplifier power to make up the difference but the ear would not hear the -3db as half as loud. If the speaker were 6 db down then that tends to sound closer to ’half as loud’ and would take 4x amplifier power to correct."

Uh, the microphone hears what the ear hears. Forget the amplifier! You’re making it too complicated. You’re hearing 20 Hz at 3 dB down. Half as loud. Example - Suppose you were listening to a jackhammer and you measured the SPL where you were standing to be 110 dB. Then you stepped backwards - a few steps at a time - until the SPL measured 107 dB it would be then half as loud. 3 dB down.  Case solved.