QSI and Walthers RS27

Hi: I have an analogic Walthers (Proto2000) Alco RS27 ansd I want to install a QSI Revolution U sound decoder.

Which speaker type or size is recommended ( mini oval?)

Which part of the loco is suitable to put the speaker ( fuel tank, inside the shell?)

Thanks

I have two DCC equiped RS-27’s with factory sound. The speakers are round, about 1 1/4" in diameter, and mounted vertically in the shell just behind the cab, and there are two speakers in each unit.

I think thats the factory A frame speaker set up,mite be a bit difficult to duplicate ,even for someone very experience …Id get with Bruce @ lichfield station and see what he recommends . but Id guess the oval in the hood area would be a good start ,but thats a guess. yep ,Id ask Bruce…Jerry