What does is mean when a bowl is tuned to "Perfect Pitch 440hz."
440hz tuning is the international standard for tuning instruments. What this means is that the middle A note resonates at 440hz, and all the other notes higher and lower are tuned in relationship to that A being 440hz. So when you see a bowl that is tuned to perfect pitch 440hz, it does not mean that the bowl resonates at 440hz. What this means is that the bowl is in tune to middle A resonating at 440hz.
What does is mean when a bowl is tuned to "Perfect Pitch 432hz."
432hz tuning is the same concept as 440hz tuning above, however, instead of the middle A resonating at 440hz and all the other notes being tuned in relationship to A being 440hz, now middle A is going to resonate at 432hz and all the other notes are tuned in relationhip to that. Because the middle A is 8 hz flatter than standard tuning, all of the bowls that are tune to 432hz are going to be slightly flatter. Some consider this to be a more enjoyable tuning to listen to.
What is Cent Value?
What is the definition of a Perfect Pitch 440hz Crystal Singing Bowl?
To understand this, first you need to understand the term "cent value." Cents is a modern way of distinguishing small variations in pitch. In modern music there are the standard tones - C - C# - D - D# - E - F - F# - G - G# - A - A# - B. However, there are also plenty of sounds that occur in between these notes as well, and through the idea of cent value we are able to classify the whole spectrum of sound. Each cent value represents a tone, and according to cent value, there are 100 cents (or tones) between each note (C, C#, D, etc.). Please refer to the graph below. As you can see, if the tone is at 0 cents, then it is a perfect pitch 440hz tone. So a 0 cent C# tone is perfectly in line with 440hz tuning. There are 100 cents (or tones) between a C# and a D. If you have a +45 cent C# note, it is +45 cents sharp of a perfect pitch C#, but not quite sharp enough to be considered a D. If you have a -45 cent D note, it is -45 cents flat of a perfect pitch D, but no quite flat enough to be condsidered a C#.
|----- (-50)----(0 C)----(+50)----|----(-50)----(0 C#)----(+50)----|----(-50)----(0 D)----(+50)----|
In the crystal bowl world, Perfect Pitch 440hz is considered as anything -10 to +10 cents. '0' cents is absolute perfect pitch, however, most musical schools of the west state that the normal human ear does not hear the distinction below 10c of variation, so the crystal bowl industry determines that anything within +10 to -10 cents is 'perfect pitch 440hz'.