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

Mapman
Compensating with equalization is then analogous to using performance enhancing drugs. that is assuming the amp and speakers can handle it.

Mikapen
I also boost a bit with controls, to accommodate the Fletcher-Munson effect at low listening levels, if i think about it.

The lowest frequencies produced by almost all musical instruments are not as low as commonly believed. For instance, whilst 28Hz was above stated as being produced by an upright bass, that instrument's lowest note---the E string played "open", is actually located at 42Hz. The 4-string electric bass (often incorrectly called a bass guitar, even by John Atkinson, who should know better) produces that same note and frequency as it's lowest.

There are a few instruments which produce frequencies lower than 42Hz, including pipe organ, grand piano, and contra bassoon. Some recordings made in very large spaces---cathedrals, concert halls---contain the very low frequencies those rooms support. The ability to reproduce those very low frequency "room sounds" is one of the benefits of good subwoofers. A good recording of a pipe organ played in a cathedral will contain the "shuddering" sound that combination produces. It is an enormous, massive, thrilling sound!

• LF extension without distortion figures is kind-of meaningless
• Most sounds below ~32Hz are from environmental noise rather than music
• Room size and in-room response is a huge factor. It’s one thing to achieve flat response to 20Hz in a closet or Honda Civic vs. a 5,000 cu. ft. listening room
• We have not very clearly defined "speaker". For example, the DuNu DN2000J is a lot smaller than the Triton II+ and are fairly flat down to 5Hz with low distortion. It can do this because the "room size" is only a few cubic mm.

The Kii Three was designed to provide extremely deep bass from a relatively small and surprisingly lightweight cabinet. An additional objective was to create dispersion characteristics equalling those of a flush mount monitor, notwithstanding the relatively narrow baffle. The smaller the loudspeaker front, the earlier (higher in frequency) the speakers dispersion will become omnidirectional – an unwelcome property in loudspeakers that studio planners go to great lengths to avoid.

Room acoustics issues appear predominantly at low frequencies and when trying to achieve precise stereo imaging. While the latter can be optimized by comparatively simple measures, taming the low frequencies takes a much larger effort (see also our special edition Room Acoustics and Studio Design, June 2016). This is where the Kii Three comes in, creating a consistent cardioid sound field all the way down to just short of 50Hz, then gradually becoming omnidirectional below this point. With the Speaker placed close to a wall and thus at an acoustically benign boundary distance, the resulting level increase below 50Hz can easily be treated in a compensation filter.

All this complex signal processing costs the user dearly – not financially, but by introducing a latency of 90 milliseconds which would disqualify the Kii Three for any kind of real time work in the control room. To avoid this, the monitor can be set to a low latency mode by pushing a button marked “P/R“ on the back panel, reducing the latency to only a handful of DSP samples plus the DAC latency for a total value in the one millisecond range. The low latency mode replaces the highly complex low frequency filters by simplified algorithms, leaving the sonic properties of the monitor basically unchanged. The only tradeoff is reduced precision at low frequencies, but at a very reasonable magnitude with only small impact on aural evaluation.

Wow tostado, a piano tuner! Man, that takes a real good ear and lots of training. I worked with one pianist who wasn’t much of a player (he grew up in the era of the British Prog Bands, hence couldn’t play rhythmically to save his life) but was a competent tuner, which is what he ended up doing as a career. Surprisingly, a lot of real good guitarists had a hard time tuning before the invention of the electronic tuner. They would get each individual string close, but chords would still sound sour. The only guy I played with (R.I.P.) who was great at tuning a guitar had perfect pitch, and playing with him spoiled me for most others. Pianos, with two strings per key and many more keys than the six strings of a standard guitar, are much, much harder to tune. Twelve-string guitars are notoriously impossible to keep tuned for very long, especially the thin-necked Rickenbackers. Jim McGuinn was always out of tune on live Byrds shows!

But yeah, real low frequencies don’t sound like a "note" being played. And a lot of criticism of subwoofers sounding fat, bloated, slow, etc., is more the result of "room boom" (dimension-related resonances/standing waves), the very low frequencies the sub(s)are playing exciting the room modes/nodes that aren’t excited without the sub(s). One of the benefits of dipole woofers and subs is that they excite fewer of those room dimensions (the length not the width, if firing down the length of the room), the result being less room boom. Harry Pearson long preferred the bass panels of the Magneplanar Tympani loudspeakers (a dipole, of course) for their very taut, lean bass and midbass, in preference to omnipole dynamic cone woofers in enclosures. Some fanatics still use the Tympani panels as woofers/subs, and GR Research in conjunction with Rythmik Audio offers an Open Baffle/Dipole sub that uses a pair of 12" woofers mounted in an "H-frame". State-of-the-Art bass!