alex_holden Posted August 28, 2021 Share Posted August 28, 2021 3 minutes ago, ttonon said: I may be wrong but I think you totally misunderstand the purpose of the table I presented. I'm not trying to design reed cavities using Helmholtz theory. I'm suggesting that the choking we observe, especially with the higher frequencies, is when the air resonance in the cavity matches close enough the fundamental of the musical tone. Air resonance happens in most all musical instruments, although the free reed is exceptional in that it occurs only sporadically, without a well understood benefit to the musical tone. I also suggest that a match with one of the lower partials can also cause problems. Once you understand the self-excited vibration of the tongue you will see the sense to this suggestion. Are we talking about two different phenomena? What I think of as "choking" is when the pressure quickly goes from nothing to 'very high', the reed gets immediately pulled part way into the vent opening, blocking the airflow and preventing the oscillation cycle from starting up. If you bend the reed up slightly so there is a larger gap at rest, you need to use higher pressure to make the reed choke (but the reed doesn't start as easily at low pressure). This effect also happens on my tuning bellows, which doesn't have a chamber between the reed holder and the bellows cavity. It sounds like you are describing the situation where a particular chamber just doesn't work for a particular pitch. The reed mysteriously won't sound, or it's very weak. You change the size of the chamber and it starts working again. I've occasionally seen that happen while experimenting, though luckily not in an instrument I built. 1 Quote Link to comment Share on other sites More sharing options...
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