Explore our 13 inch frosted crystal singing bowls. The 4th octave D is the major note of a 13 inch bowl. You can as well find many 3rd octave notes in the 13 inch size: 3rd octave F, F#, G, G#, A, A# and B. If you are looking for lower toned bowls, then 13 inches is a great place to start. 13 inch bowls can start to have fairly long sustains, some bowls lasting up to 35-40 seconds.