The short answer
Sustain is the length of time a bowl continues vibrating after excitation, but a meaningful comparison requires a defined measurement method. ANURAVA should report sustain under a standard strike, recording setup and decay threshold rather than relying only on what one listener can hear. Longer sustain is not automatically better; response, tone and controllability matter too.
Measured by ANURAVA
Why “rings for about thirty seconds” is not a measurement
A sustain figure depends on how hard the bowl was struck, what it was resting on, how quiet the room was, and — above all — the point at which the observer decided the sound had stopped. Change any of those and the number changes. Quoted without a method, a sustain figure is not comparable between two instruments, let alone between two sellers.
The ANURAVA definition
Measured by ANURAVA
Sustain is measured from 100 ms after the initial level reference until a smoothed RMS envelope has remained at least 40 dB below that reference for 500 ms. The value published is the median of three controlled strikes, and the background level of the room must sit well below the threshold for the reading to be valid. The threshold and the method version are stored with the number.
How a value is reported
Sustain: 28.4 s — median of three standard strikes to −40 dB, Method v1.0. The figure shown here is a format illustration, not a measurement of any instrument.
Longer is not better
A very long decay is useful when you want a sound to hang over a room. It is a liability when you need to play a sequence, because the previous bowl is still sounding when the next one arrives. Practitioners building sets often care more about how cleanly a bowl stops than about how long it continues. Response, dynamic control and tonal fit all compete with duration, and the right balance depends on what you are doing.
Different partials fade at different rates
Acoustics / physics
Decay is not a single slope. Upper partials commonly fade faster than the lowest mode, so the character of the sound changes as it falls away — bright and complex at the start, simpler and purer near the end. A single sustain number compresses all of that into one figure, which is why a decay envelope or spectrogram is more informative for research purposes.
Frequently asked
What does sustain mean?
How long a bowl keeps sounding after it is struck or rubbed. The figure is only meaningful alongside the method used to obtain it.
How is singing-bowl sustain measured?
Under the ANURAVA method, from 100 ms after the initial level reference until the smoothed RMS envelope stays 40 dB below that reference for 500 ms, taking the median of three controlled strikes in a room quiet enough for the threshold to be valid.
Is longer sustain better?
Not automatically. Long sustain suits single strikes and open spaces; shorter, cleaner decay suits sequences and ensemble playing. Response and tone matter alongside duration.
Sources & methodology
- First-partyANURAVA Acoustic Method v1.0 and Sound Passport recordsANURAVAFirst-party measurement protocol and per-instrument documentation.
Written and reviewed by ANURAVA. Where a statement rests on a musical convention or a traditional association rather than on measurement, it is labelled as such in the text above.