How do you install a speaker in a SD-45 or GE-8-40?

[DuceNova]

I'm in the process of installing decoders with sound in all my HO deisel locomotives.

The F series locomotives have just enought room to fit a 1" speaker with very little work.

BUT the GP stye locomotive I've done so far have been a PITA.  A 3/4" (28 mm) just barely fits in there and don't have the sound volume or quality that the F units have.

Can someone pleae enlighten me as to how mount them so they sound better?

[ABC]

Try milling it out to make some space for a larger speaker and baffle, and removing anything not entirely necessary, and possibly reallocating some parts.