Indeed, all my capture settings include absorption, reflection and diffraction. I've even tried to cut feedback by superposing straight and circular slots, horizontal or vertical in order to generate exctinctions by interferences but there is always some frequencies whiches are amplified and the complete extinction comes when microphone is almost encapsuled, sound capture is greatly damaged.
Yeah, I did that and more I'm sure you can't imagine, I even thought about microphones triangular diaphragm cause maybe the weak resonances can prevent feedbacks

I know I don't look earnest but I learn on the go and my last set is almost ready to allow me to reach quintessence ( philosophic way ). Actually, I've already reach quintessence when I listen to music cause no feedbacks ( I don't use the microphones ).
Microphones are very sensibles, large diaphragm and are placed next IEMs whiches deliver 50dB low and trebbles, and 80 dB mediums ( those levels are comfortable, I can increase and decrease a bit ). It's really hard to prevent feedbacks without DSP but it works well when I design the waves flow.
Just this fucking 2.5kHz feedback, in real situation, prevent me to use completely my left ear, and the right so because I need to balance stereophony. I cannot block this, and it's possible feedback comes by conduction, trough the ear support... Which case I've no solution...
And, I forgot to precise, I accept ideas about IEMs isolation
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