[Click on image to enlarge.] Figure 1. A standard piano features 88 keys (white and black) representing notes that span from A0 (27.5 Hz)  to C8 (4186.0 Hz), with “Middle C” or “C4” (in yellow) on the keyboard located at 261.6 Hz. In terms of frequency, Middle C is 1.059 times higher than the key to its immediate left (ie, B3 at 246.9 Hz). Looked at another way, every time you move 11 white and black keys to the right, you double the frequency in Hz (ie, 12 keys per octave as shown with the key of A above). This illustration also demonstrates why music is predominantly a low-frequency acoustic event. As hearing care professionals, we are obsessed with speech audibility and high-frequency consonants, and fixate on only a relatively small portion of the musical spectrum—namely, the 25 right-hand piano keys above 1000 Hz. In fact, 74% of the Audibility Index is weighted for tones above 1000 Hz.


The Importance of 1.059 in Music (and Audiology)

Why is the number 1.059 important in audiology and music? Besides being the twelfth root of 2, it is also the number you multiply by in order to find the next key on a piano keyboard (in Hertz). Marshall Chasin, AuD, explains why this knowledge might come in handy.