What is pink noise?

Alcides - your pink/white noise analysis is correct, but you're off by an octave on the piano's low end. The standard 88-key piano goes down to ~28Hz, also the 440Hz A is above middle C, not below.

So if you were going to measure in-room frequency response, would you use white noise or pink noise?
And how do you measure sound at any particular frequency? Rat Shack SPL meter and Stereophile test tones miss a large part of the frequency spectrum. I would think using white or pink noise would be much more accurate - IF it can be done.

Hearhere... whoops... atleast I got middle C right.

261.63Hz if you do the math... Where's my drink?

Cdc,
If you must use a broadband noise signal, use pink noise. White noise will be irrelevant. If you use a broadband noise signal like pink noise, you need to have a spectum analyzer to really be able to measure the in room response. These will generaly give you a graphic display with frequency on the x axis, and absolute level on the y axis. Much like the graphs we all see in Stereophile etc. Measurments of this type get tricky and expensive.

Stereophile's discs do miss much of the spectrum, but what they include are tones that actually apply to areas in your listening room that you might actually have realistic control over. They also assume the average listener is going to have a radio shack SPL meter that has poor frequency response in the low and high end.