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

Actually here is what the ear hears and its far from flat at the extreme top and bottom range of our ears in particular:

http://www.independentrecording.net/irn/resources/freqchart/ear_sensitivity.htm

For example according to this what measures correctly as flat at say 20 hz will be heard down more than 70db by the typical human ear in the worst case at the lower volume limit of human hearing. Less so but still down at higher volumes. So significant equalization/boost is needed to "hear it as flat". How much depends on volume. Same true with the high end.

Whereas a microphone used to measure the levels accurately would have flat response end to end. Our ears are far from that as shown in the chart.

mapman OP
"Actually here is what the ear hears and its far from flat at the extreme top and bottom range of our ears:

http://www.independentrecording.net/irn/resources/freqchart/ear_sensitivity.htm

For example according to this what measures correctly as flat at say 20 hz will be heard down more than 70db by the typical human ear. So significant equalization/boost is needed to "hear it as flat". Same true with the high end."

That’s absurd. You will pay big bucks to hear 20 Hz 70 dB down? Are you crazy? 70 dB down is almost as low as the noise. Besides, you're the one that says it's flat at 20 Hz. Hel-loo!

Its not absurd at all. Its a well documented fact.

Turn the volume up and things are better but still far from flat.

Equalization is the only practical solution if one truly cares beyond that.

It helps to manage expectations though to realize and understand that what we hear is not the same as what measures as flat.

If the speaker rolls off at extreme frequencies, then we hear even less.    

The ability to not roll off at frequency extremes and make things even worse is what separates the men from the boys.

Compensating with equalization is then analogous to using performance enhancing drugs.  that is assuming the amp and speakers can handle it.  That's a different story.   if they can't,  then the results will surely not be good.

Wow, those Ohm speakers remind me of my old BIC Soundspan 600 speakers. 

@mapman  

There is no need to boost everything to flat of equal loudness as music is produced for human hearing in the first place / so it is balanced accordingly and a speaker should be flat overall.

One issue with flat to 20 Hz is that rooms give a natural 6db per octave boost as you drop below about 40 Hz. So ideally a speaker should have some roll off if it is to perform flat in a room. A speaker flat to 16 Hz like the ohm f-5015 is likely to sound awful in most rooms without EQ.