Time for an update, yet again?
I tried the BZ-50P on a 9V battery (yes), and it still was deafeningly loud, yup, I think I got a champion there, but…
… I found what appears to be a “High Power output” version of my AE&T/E2S T100 sounder, the T112N, this one, I think it requires 12V at the absolute minimum (won’t run on 9V, or so that’s what I have been told about these), 119 decibels… Hmm do we know how high (in dB) a Simplex 4051/4050 or a Amseco BZ-50P can go? I think I might be onto something there.