04-08-2012, 02:23 PM
Foam is very noisy. I was a member of a club in the 1970s that made extensive use of the old PFM sound system, and they had a technique of making a spline-style roadbed that had acoustic plaster applied between the splines. This was very quiet. For my current layout, I was strongly influenced by my experience in that club, but instead of the special spline-and-acoustic-plaster, I use Celotex (which is called "sound board" at lumberyards, too) laminated to 3/4 inch plywood. I've heard this is a better choice than Homasote, because it's more readily available, is cheaper, and doesn't expand when it's wet; the only downside is that it doesn't hold spikes as well, but I use flex track and cork roadbed anyhow. In addition, I followed an RMC article from the 1980s that suggested spacing the L-girder joists at a "phi" proportion interval, rather than a regular 24-inch (or whatever) interval, to minimize any tendency to develop resonant vibrations in the benchwork.
Meanwhile, sound went from PFM and similar analog systems to DCC, and I'm still not on DCC, so I don't have many sound locos, but operation is very quiet -- I've had open house visitors come into the layout room when a train is running, and they act all disappointed right away because they don't hear anything and thus don't think anything's running. People are used to visiting layouts and hearing a lot of racket from thin plywood or foam, irrespective of any sound system. Once I assure visitors that a train is in fact running, they're happy, and I suppose I should see it as confirmation that my benchwork is quiet.
Given my efforts at building quiet benchwork, I don't hear much difference in volume between Athearn RTR, P2K, or Atlas, they're all acceptable.
Meanwhile, sound went from PFM and similar analog systems to DCC, and I'm still not on DCC, so I don't have many sound locos, but operation is very quiet -- I've had open house visitors come into the layout room when a train is running, and they act all disappointed right away because they don't hear anything and thus don't think anything's running. People are used to visiting layouts and hearing a lot of racket from thin plywood or foam, irrespective of any sound system. Once I assure visitors that a train is in fact running, they're happy, and I suppose I should see it as confirmation that my benchwork is quiet.
Given my efforts at building quiet benchwork, I don't hear much difference in volume between Athearn RTR, P2K, or Atlas, they're all acceptable.