I have a N scale LikeLike FM Erie Built loco that needs a decoder and would love to hear what a Fairbanks Morse sounds like. But, it looking at a stripped down frame, I don't see any good locations for a speaker. There's only about 5.5 mm between the worm gears and the top of the loco. The fuel tank area is about the same. Has anyone tried this? I do have sound in a LL FA1, but I cheated and de-motored it. I would prefer not to do that again.
Bill Kepner
Hi Bill.
I haven't done one of these myself, but I have an idea after looking at the photo of the chassis on Spookshow's site. I assume that this is the same loco (from 2002, with one big honkin' piece of metal-type chassis, right)?
How much length do you have to work with on that chassis? It's hard to tell from the photo, but what I would do is mill as much depth off the rear of the chassis (behind the motor) as much as you can before you hit the worm gear (you indicated you had 5.5mm above the worm, so mill off 5mm?). Then use an 8x12 speaker in an enclosure that is thin, but long (longer than the speaker) with the speaker offset to one end. Seal up the offset side of the enclosure top with a piece of lead sheet (for weight) or styrene to make the box air-tight. You want to hit about 500 cubic mm of interior air space in the enclosure. So let's say you can make the enclosure out of .020 styrene, 4.5mm high including the bottom. This means you have 4mm of interior height. An enclosure that is 16mm long by 8mm wide by 4mm deep gives you an interior volume of 512 cubic mm. A Soberton 8x12mm speaker in an enclosure like this will sound fine.
Here's a photo of the kind of enclosure I'm thinking of, except the speaker would be turned lengthways, with the "extra" enclosure space at the end of the short side of the speaker instead of the long end:
That should still leave room to mount an ESU Loksound decoder toward the front (more frame milling, I'm afraid).
John C.
