Installation Notebook:
Sound Installed in Proto 2000 E9B
The powered B unit in these circa 2004 locos still has room for great sound. The Soundtraxx baffle kit mounted in the front of the shell (NOT in the rear as the instructions show) is used with a 28 mm (1 inch) speaker. A DZ143PS decoder plugs into the socket and a DSX from Soundtraxx provides the sound. A 2 pin connector between the speaker and the DSX allows for ease of shell removal for storage, etc.

The circa 2004 PB units would have the same install, except they would use the 810100 baffle kit.
You may want to review the DCC-only install in this loco: CLICK HERE