You need to find a guru for that specific Ensoniq keyboard or at least search online to see if there isn't a downloadable owner's manual for it.

I suspect that there is an setting internal to the Ensoniq that must be found and set to the right setting.

It is a very old keyboard as MIDI goes, may not be GM compat, which can be worked around in BIAB with reassigning of instruments. If it is playing the BIAB instruments and sounds like what they are labled in BIAB, then that is not a problem.

Look for settings such as, "MIDI Echo" or "Local On/Off" in the Ensoniq, experiment with them and BIAB one at a time.

And welcome to the fun!

--Mac