I’m sorry it’s not the ‘Holy-Grail’ here; great that it worked for you, but in reality it doesn’t apply across the board. Hearing technology has moved past this point.
I used my phone and a Compilot 2. It was transmitted. It was not through the air. I cycled through a big range of frequencies to see where I’m missing some sound. It is not the hearing aids that have dead spots. It is my ears.
My only fix for my dead spots is to move those sounds to a range without dead spots. So I moved Sound Recover lower and lower until my tone generator did not reveal any dead spots.
If the hearing technology industry doesn’t test for dead spots, how would they know my frequency range needed to be lowered/compressed?