One of the Christmas presents I received was a gorgeous Tibetan singing bowl. These are bowls used during meditation and can be struck or made to “sing”. When struck, their rate of acoustic decay is very slow. When you rotate the mallet against the outer edge in a strong but steady way then the bowl sings; it begins to vibrate at a steady rate and produces a very pure tone.
Here’s an example of the struck tone:[audio:https://iansidden.com/wp-content/uploads/2012/01/Struck-tone.mp3|titles=Struck tone]
Of course, I immediately began focusing on the quality of the tone itself and ran it through my power spectrum software. The struck tone tends to be full of stronger overtones than the sustained tone. But the overtones don’t initially appear to be part of the harmonic series. It seems that there are several distinct tones happening at once that aren’t necessarily harmonics of a fundamental pitch. But I need to do this analysis at the school where I can have a less noisy environment than my home.
The two dominant tones have distinct names; they are the “male” tone and the “female” tone. The male tone is the lower frequency tone while the female is often a tritone higher (mine sounds like a slightly sharp 11th). By using the wooden part of the mallet against the rim of the bowl, you can isolate the female tone while the suede or wool part of the mallet used lower against the bowl walls can produce the lower male tone.
This next audio example is of the male tone. It’s extremely pure and beautiful, and it carries well throughout the house – sorry, Rebekah![audio:https://iansidden.com/wp-content/uploads/2012/01/Sustained-tone.mp3|titles=Sustained tone]
You can hear that I’m not a singing bowl master just yet. I suppose that’s what practice is for.
For more information, check out the excellent blog The Secret Life of Singing Bowls.