Sound proofing.

[Builder]

As can be seen, i am new here,, and want to build a new project, I have read through most posts on baseboards,(not all) there is so much info on the forum, so i am asking if there is a thread i missed about making the base as quiet as possible? a combination of insulation,sound absorption, and insulation ? I remember my older efforts being very `rumbly` and my current effort is in the time honoured 1/2in ply with 3mm corkover, and most of the track on a foam and balsa substrate, which i consider to be noisy and intrusive,even at slow speeds, especially as i would like to do 7mm narrow gauge with DCC. Any thoughts or advice People ?

[TimberSurf]

High, I wrote this a while back, no definitive answer, the jury is still out, as I only have two short boards and am unable to run fast trains.
I think the pertinent point is not to put down lots of insulation material then use PVA glue that then reconnects the track to the board. I have used 50/50 Copydex and it seems to work.

[Mountain]

I've never tried soundproofing as I dont mind baseboard noise. Surprisingly the quietist surface I've tried is track layed outdoors on concrete!
One cheap way is to buy rolls of thin polystyrene wallpaper insulation that one puts up before wallpapering. It used to be very popular back in the 1970's and before and has in recent years made a come back. It is much cheaper then cork. A club layout I used to run trains on used this and it was nice and quiet in use.
Will you be using Peco 0-16.5 track? (00 code 100 can be used for behind the scenes).

[MickleoverTestTrack]

I think I've got about as quiet as it is possible to go. Celotex base with the alu skin cut and peeled off under the woodland scenics track bed that I glued with copydex. I haven't ballasted yet but according to what I've read, Copydex makes for a much quieter result when you do.

I wouldn't recommend the celotex as a board, the traditional solution still seems like the best. The Woodland Scenics track bed seems to do more for the noise than the board.

[Emettman]

My older (ancient) baseboards had cork on top of a chipboard surface. Not desperately quiet, but not a problem in what was mainly exhibition use.

I have used Celotex (or equivalent) as a board material as I like the light and strong combination this can deliver for portable layouts, but the metal skin is a vital component in that use.

The boards do seem a bit boomy, but decidedly better with a trackbed of soft EPA foam rather than cork, and the ballast grit added with Copydex or a "stay flexible" PVA.

Chris,

[MickleoverTestTrack]

I have used Celotex (or equivalent) as a board material as I like the light and strong combination this can deliver for portable layouts, but the metal skin is a vital component in that use.

Just to clarify, I left most of the metal skin on mine. It was just a strip under the track I took off on one side. I haven't run enough to know if it makes a difference to the noise but it certainly hasn't affected the integrity of the board.

[Bigmet]

Three principles to work with.

1 Least possible sound generation makes a big difference. Quiet mechanisms are available, use them for preference.

2 Avoid coupling the vibration on the rails to the layout structure as much as possible. We want inefficient coupling!

3 Avoid large and resonant baseboard area and materials. This acts like a drumskin or horn loudspeaker to efficiently couple the vibration to the air mass, where it will be heard as sound. When using ply, a trackbase that is only the width of the track bed is the best plan, not so much drumskin. It means more constructional work, but there can be an economy in material in compensation. I have seen acres of expensive ply only supporting light weight scenery, which could just as well be a papier mache shell over cheap cardboard.

... I haven't ballasted yet but according to what I've read, Copydex makes for a much quieter result when you do...

That's principle 2. A flexible adhesive is less efficient at transmitting the vibration: and don't put any permanent pins through the sleepers either, they couple track to structure very efficiently. Except perhaps where the track runs over a steel bridge for the contrasting rumble?

...Surprisingly the quietest surface I've tried is track layed outdoors on concrete!...

That's principle 3, the material isn't that resonant to small mechanism vibration due to mass and probably has a small surface area.

[Builder]

Thanks for the input, I also thought about the `tethering` of the track being a lot of the noise transmission, things like pins into the baseboard, and PVA glue used on the cork, and ballast?

Is there an alternative way to ballast tracks? Perhaps i need to look farther into the annals to find more info! As i said before ,there is so much knowledge here, that it will take me months to go through it all! ! so please excuse my questions which have undoubtedly been covered somewhere!

A last question for the moment, this Celotex board, is the 25mm thick one the one to use? i thought that maybe a much thicker one may be better, plus it raises the track bed if cut to the contouring required , a bit like the open base systems i have seen, where decent sized viaducts,bridges,etc can be incorporated? this would be onto the ply, with copydex, or has it been tried with silicone adhesive ? maybe that will insulate a bit more?

So, again, thanks for the advice, Jim.