What determines the threshold air pressure to sound a note?
Thu, 05/22/2025 - 08:21
I've got a few harmonicas that seem to have a reed that need more "oomph" than the others -- my A harmonica's 6 blow, for example. If it were always the 2 draw, I'd figure it's me and not the harp. And maybe it's still me and not the harp, but it got me wondering...
Does gapping or embossing or some other tuning thing lower the threshold (how much you need to blow/draw to get the same volume)? Are some reeds just stiffer than others? Is getting the hang of how much each reed needs from you just part of learning your harmonica?
Thank you very much!
The mass and weight distribution of the reed itself plays a part - the heavier it is, the more air flow will be required to get the reed to budge and to remain in motion.
Profiiing, gapping, and airtightness of the slot-to-reed tolerance, as well as air leakage via the comb-to-reedplate mating, can all play a part - more air leakage awa from the reed, the more it take to give the reed the flow it needs.
Player technique can also play a part. If your oral cavity resonance is set to something that works against the vibrating frequency of the reed, then the reed won't budge unles you force it instead of persuading it.