I'm taking the plunge and am about to begin a Tsunami sound decoder installation in an Intermountain Railway AC-12 that I previously installed a Digitrax decoder (no sound) in. I've noticed in some sound decoder installation articles in Model Railroader magazine that no mention is made regarding providing holes in a diesel locomotive for the sound to escape. I would prefer not to have to deal with all the "plumbing" on the underside of the tender if/when I drill some holes in it.
Does anyone have an opinion regarding the necessity of holes for decent sound performance. Needless to say, the AC-12 has a rather large tender. I have a speaker enclosure for the 1" diameter speaker that was recommended by Soundtraxx.
Well I have a different idea on the speaker install. First off an AC-12 is an oil fired locomotive so there will be no coal load to put holes into. I would use a 27MM high bass speaker and mount it to the floor.
You will need to some holes in the floor to let the sound out. The tender shell will be the enclosure. I would not use the enclosure. The tender shell is the enclosure.
I have done many just like this and the sound is great!