Before I get too involved, has anyone installed DCC and sound in an Athearn BB F7A or B? The DCC is no problem,but probably would be a TIGHT squeeze for the sound...esp the speaker. The F7A has the large super power weight inside. The B unit has the same. I do have F7A & B DUMMY units too.
Parts at the below site. Store the link in Favorites. You will need it.
http://www.soundtraxx.com/choose/step3.php?t=ho&s=Athearn
Rich
Look below.
http://www.modelrailroadforums.com/forum/showthread.php?t=11491
http://qsisolutions.com/products/techinfo/revolution/q-revo_installations.html
I did a search for athearn f7 sound install. There may be more. QSI is another possibility. I just like the Tsunami decoders.
Rich
I installed some soundtraxx DSD decoders with #810112 speakers in my athearn F7's. I left the weight out and mounted the decoder to the top of the motor with double-sided tape. For the speaker, I made a enclosure and mounted it on legs to the framerails above the rear truck. Once the weight is removed there's plenty of room. I usually run mine A-B or A-B-A so I don't really notice any loss of pulling power. Don't have any pictures my install, but could post some tonight if interested.
You might give the MRC "Generic Diesel" Universal Sound Decoder a try. It comes with a baffled speaker and an 8-pin plug connector on the wires. It's easy enough to remove the plug and hardwire to an Athear BB loco.
A little work on the weight with a hacksaw and file should create a space for the speaker. It's available from Walthers (PN: 500-1669) for around $80.00.
Len
The problem with sound in diesels is to produce enough low frequencies to make them sound believable. Tiny speakers in miniscule enclosures just cannot do it. What you might consider doing is mount your sound decoder and speaker, or better, speakers in a dummy B unit and seal the shell to make a decent sized enclosure out of it.
Jim