The locomotive makes sound so there has to be a speaker, right? 

The locomotive in question is a Walthers Proto GP60 with DCC and Sound. I bought it to learn about synchronizing sound with engine movement, momentum, braking, etc. Things were going fine so naturally I did not leave well enough alone.

I resolved to install a sound decoder and speaker into a non-sound, DCC ready GP40-2 as part of my perpetual learning curve. During the search for an appropriate speaker I thought it would be good to see what was already in the GP60. Couldn't find anything that looked to me to obviously be a speaker.

The photos are a top, side, and more or less 45 degree view of the chassis. Unless it is that hyper-miniaturized rectangular silver object on top of the cab light board, I guess the speaker has to be inside the red lines I drew on the images. I could see enough into every other area to verify absence of a speaker. Oh, and there is nothing in the shell.

Further disassembly in the red outlined area is going to disrupt a lot of existing wiring and solder joints so I stopped in order to ask if someone knows about this loco and/or has seen what type speaker it uses and how it is situated.

Thanks.