I tried a couple of physically larger microphone Tx and the response is
essentially flat from 2Hz (the bottom limit of my sine gen ) and about 20KHz
, rapid tail-off after 30KHz.
So will try one or both of them when I get back to this speaker/PA problem.
RTFM time : the "shape" switch on a Roland cube 30 bass does not switch in
and
out the COSM selection. I think there was a problem in this sw and when the
wiper disconnects then the function stays with whatever was selected before,
the control lines stay high.
Incidently if o/c at switch on then disables the amp totally. The speaker/PA
is perhaps fine after all , but will try comparing at some point , to at
least see if microphone Txs are useful for this