I plan to use extruded form sheet as my layout base; over open grid benchwork with cork roadbed. I used this method before, but some have mentioned the dreaded “drum-effect.” I honestly never noticed it on my previous layout.
Is it something I should consider, and if so - how to ameliorate it?
If you build your frame and cover it with 1/2" plywood befor the foam, you shouldn’t have a drumming problem. The 1/2" plywood is thick enough that it absorbs instead of resonating any sound vibrations.
Joe
The second level of my layout is exclusively 2" foam attached to wooden cross members supported by various types of shelf brackets and secured with latex caulk. I’ve never experienced “drumming” but my layout is a secondary main line with only 1 or 2 trains running at any given time, at relatively slow speeds.
I would suspect if I has running multiple highspeed mainlines, withs lot of multi-unit consists, there would be substanitally more noise.
It really may depend on what you plan on running.
Scott Sonntag
Dual densities has a marked effect on vibration dampening. Yes, your peripherally supported foam will act as a soundboard. But, support it below with two thin 1X2 joists, and glue the foamboard to the tops of those joists with a thin layer of cheap acrylic caulking, and you’ll find it quite a bit less noisy. Maybe not half as much, but close to.
One other very critical problem: hardened ballast making glued contact with pretty much any supporting medium will be noisy. So, going back to dual density, we use homasote, cork underlay, foam roadbed, even plywood or strips of drywall (you wouldn’t believe how quiet drywall is). But, if your glued ballast spills over that roadbed and makes hardened contact with the base…see above.
All this to say that if you isolate the hardened ballast and trackage from the main base, no matter what that base is, it will be quite quiet. If you have a bridge over a river or chasm, note how quiet the trains are over that bridge. Amazing.
I have found that what is on the floor beneath the layout is more important. I had the same 5’ x 10’ layout set up over a hardwood floor, porcelain floor, and carpet. There was a noticeable difference between the three.
All out methods produce a drum effect, if it really bothers you you can seal the bottom with plastic but the effect has never bothered me.
One option is to use foam roadbed. WS makes this stuff. Works well. Has more give to it than cork which some people don’t like. Cork is more rigid than foam from a sound transmission perspective but does absorb some frequencies. Mother nature’ closed cell foam.
I have wanted to try this for awhile.vinyl flooring uses an 1/4" foam underlayment thst comes in a roll. Thought I might cut that in strips and use it directly under the track after spraying it grey.
P:eople use cork for a reason, you can sand it smooth and carve in transitions, can’t do that with the WS stuff.
after reading an article about it in MR some 11 or 12 years ago, I decided to try it. Dead quiet even over foam and per strip cheaper than cork.
shane
I’ve never noticed any particular sound problems with foam…
Drumming is caused by the trains vibrating the subroadbed, which is caused by a lack of mass or density.
If you made your subroadbed out of 2 inches of concrete instead of 2 inches of foam, there would be no drumming.
What ever you use, secure it well so it eliminates the little vibrations the best you can.
How about sound deading foam shoved up inside the box, less than 50cents a sq ft.
I’ve used WS foam roadbed over pink foam that was glued to a wood ladder-type framework. I’ve seen no increase in noise at all.
You can slice WS foam underlay into an incline using their foam knife. However, using WS inclines is much easier and gives a nice accurate 2% incline.
Interesting observation, so how did the three flooring options rank from best to worst? My guess is carpet is best and ceramic was worst… Close?