How low is a piano?

Harmonics of the piano are much more complex than regular overtones. It resembles a little percussion instruments but it might also be due to tempered tuning of the piano: http://www.precisionstrobe.com/apps/pianotemp/temper.html

Benchmark Media technical director John Siau mentioned once that warm sounding gear (enhanced even harmonics) can make piano sound like out of tune. He also mentioned that because of crossovers in speakers the best piano sound can be reproduced with good headphones.

The Bösendorfer 290 does not extend a full octave below the standard 88 key piano. The 88 key piano goes down to A0, the 97 key Bösendorfer 290 goes down to C0, approx. 16 Hz, an additional 9 keys, a little more than half an octave extra.

http://www.boesendorfer.com/en/model-290-imperial.html

Very interesting responses folks. Thanks! Am I correct about the low bass string? I wasn't sure.

Actually it's 41Hz in standard tuning.

Grimace - You are correct (41.2Hz). There are 5 or 6 string electric bass guitars that have additional B string (31Hz) but it is made only for ease of playing. Composers would avoid writing music for 5 or 6 string instrument exclusively where most common bass has 4 strings.

I wonder why they produce instruments like Bösendorfer 290, that go below human hearing. With church organs vibration could be felt - is it the same for the piano? I though for a moment that perhaps it was designed for dogs but in spite of common "superior hearing" belief, dogs don't hear below 60Hz. It must have been for whales!!!