Octave is the musical term for doubling the anchoring frequency. This is do, re, me … back to do. If you start at a 55 Hz A1 (A1 = the note A in the first octave) that second “do” will be A2 (A in the second octave) at 110 Hz. As your octave number increases so does the pitch, higher and higher. The next doubling brings you to the third octave, fourth and so on.
The primary tone in singing bowls is the one you first hear when you strike it with a mallet. Typically this is the lowest tone in a bowl. The deepest singing bowl I’ve measured has been a C in the second octave, the highest go well into the sixth octave, over 1000 Hz.
Perfect or concert pitch is a single point in the spectrum of tones that comprise a note. Musicians hear this spectrum in terms of “in tune” or perfect, sharp and flat. A sharp note has a has a slightly higher pitch than the perfect note, a flat slightly lower. For an even finer distinction musicians divide each note in the musical scale into 100 musical cents – 50 sharp and 50 flat. It is a rare person who can hear the difference of one musical cent. Perfect pitch then is defined as a range of very slightly different sounds in the center of the full range of tones for a given note.
If you allow for the limits of most ears then the middle 20% of a note – plus or minus ten musical cents from absolute center will qualify as perfect or true tone. A musician with trained hearing might argue for a tighter standard. Many people would still not be able to tell with a loser standard.
Since nobody in the Himalayas ever made one of these bowls with the Western music scale in mind it is rare to find one that is exactly top dead center of the note it is closest to. For the most part they are above or below the exact note, pretty evenly distributed between sharp and flat. Statistically, then , only 1% or the one cent in a hundred will have the absolutely perfect or concert pitch and about 20% will have the more generous range commonly used.
To make things a little more confusing, just like there is not an exact definition of what perfect pitch is there is room for interpretation of about where the octaves start and end. The “A” note above middle C is used to peg the octaves. In Western music and the example I used above of 55,110 etc the frequency assigned to a perfect “A” is 440 Hz. Not everybody and every time agrees that 440 is the right number. It is thought that the classical composers did not write to exactly 440 Hz. Some people believe that a flatter central note of 432 Hz has a more natural sound. The effect of changing “A” is to move perfect pitch for each note to a different range. That is right every note changes, what is flat at 440 is perfect at 432.