Double click to reset

self-explainatory. the freqshift knob is a bit of a pain to get back to zero…

Did you try control-click? Actually the default for the frequency shift is 50Hz. That is to reduce the risk of feedback when using air microphones or stage setups, where the piezo disc is attached to a potentially resonating body, e.g. a drum.

Thanks! That’s a good idea (the frequency shift)