Not a good idea

I had a friend use this against my advise and it turned out to be nothing but a problem.  It crumbled easily on the edges and was not dense enough to hold anything you inserted into it.  This is one area where you don't want to scrimp on quality.  It's the base for everything and all the effort you'll put on top it.  Homosote is more expensive and a lot harder to find but definitely worth it in the end.

In my experience it is all a

In my experience it is all a waste of time, my layout was way quiet with plywood topped with cork roadbed until I glued the ballast down. I don't think it matters what is under the ballast and glue, once it is applied it all changes.

I must have got used to the noise as I no longer notice it but I do remember a huge difference before and after the ballast.

Thanks for the good advice. 

Thanks for the good advice.  I'll keep searching for Homasote in this area.

Thanks.  As I age past my

Thanks.  As I age past my current 70 years young (!) I suspect that "noise" will not be a problem!

Locating Homasote

Go to Homasote.com,  There is a "Where to buy" selection towards the left top of the page.  You are looking for 440 sound board from the Homasote company.  The "Sound Choice" board that you found at Home Depot is about half the density of Homasote, is made using Souther Yellow Pine dust as the material and is held together with a binder made from modified corn starch.  It will come apart with the moisture used in a lot of our scenery methods and is not dense enough for good support anyway.

As noted including down

As noted including down ballast makes all attempts at sound deadening pretty much pointless.

That is why I use mate medium.  It stays a bit rubbery and thus is not as loud.  I figured this out by accident years ago when I ran out of  mate medium and used white glue.  I could tell when the train got to that section from 30' away.  It actually worked well to tell me where my train was, but it was noisy.

-Doug

Experimenting with XPS foam on OSB on Hollow Core doors

Getting back into the hobby after a 15+ year hiatus...

Living in a community with lots of new construction, I have ready access to dumpsters containing: dimensional lumber, PVC pipe, OSB, and the occasional piece of 1/2" birch plywood.  I love free stuff.

I picked up (8) "cosmetically challenged", but structurally sound, hollow core doors (various sizes) for $3.00 each at a local lumberyard.

I've built two modules so far.   Construction method:

1.     3 1/2" H X 2" X 4" risers hot glued to the HC doors.

2.     1/2" OSB screwed to risers.  (Will augment with hot glue "spot welds" before scenery is built.)

3.     1/2" Blue Dow XPS Foamboard glued to OSB.

4.      Legs are 2 1/2" PVC pipe.  Friction fit into the sockets.

5.      Leg sockets are 1" X 6" X Door width with 2 1/2" leg holes.  1" X 6" are glued and screwed to HC doors. 

I can't detect any noise from the roadbed.   Some noise from locomotives and cars.  Sounds fine to me.
FYI, track is not fastened down or ballasted yet.    Track sitting directly on OSB does make a lot of noise though.

So far, its a winner.   The XPS Foam covers over the roughness of the OSB.  I wouldn't want to lay cork, Homabed, or track directly on the OSB. 

My roadbed is 1/2" higher than the surrounding scenery will be. 

I will contour the foam roadbed to 30 degrees using a hot wire knife once the track and wiring are finalized.
 

After Ballasting

It would be interesting to hear the results of your sound deadening after you ballast.

Now you have me

Now you have me thinking...

My other hobbies are playing in rock bands and live sound production.

I've got lots of reference microphones and mixers that I could plug into a laptop, iPad, or iPhone to objectively measure sound levels.   I need an App that makes this cheap (free) and easy.  I don't have a much time to fool around with this, but if effort and cost are minimal, I'd be willing to give it a shot.

You could just tell us. I

You could just tell us. I believe the reference was to how much noisier it will get after ballast and glue dry and transmit the vibrations to the osb and then you will hear it. Many methods are quiet until the application of ballast, but real trains are noisy too.

What about ceiling tile?

I've heard that some folks use ceiling tile (ie the 2' x 4' tiles for drop ceilings).  How does that compare to Homasote?

Thanks,

Ed

Analysis

Dear Walker,

If you really want to go there, try this:

- use the flattest-response mic you have available
(a Shure SM57 would be better than a 58, but neither are "flat" in terms of frequency range sensitivity!)
 
- at a perscribed and rigourously-stuck-to distance and angle/direction from the test subject
(IE test ALL examples with the mic _the_same_ distance and angle/altitude from the subject-under-test)

- in as-quiet an environment as you can muster
(ANY external noise will sho up in the recording. Momentary noises such as car horns can be ignored,
but any low sustained sound like a droning A/C unit will likely skew the test results...)

- Record at 48khz 16bit, or 24-bit if your gear allows, in PCM WAV format
(we are trying to _eliminate_ digital audio or data compression artifacts from the signal path,
MP3, OggVorbis, AAC, AIFF, or other audio formats Need Not Apply)

- download and install the FREE TRIAL version of IzoTope RX4
https://www.izotope.com/en/products/audio-repair/rx/

- Literally drag/drop the test recording into IzoTope

and screenshot the results...

IzoTope RX4 is a forensic-grade frequency and amplitude spectral analysis tool,
and should be able to give some very accurate Empirical Insights into what you are actually hearing...

For examples of previous Good Audio Science testing from here on the MRH fora, reccomend re-reading thru Pelsea's "Foam Drum" threads

http://model-railroad-hobbyist.com/node/15325

http://model-railroad-hobbyist.com/node/15420

And Duck Dogger's onboard-sound/speaker analysis thread (Inc example IzoTope analysis posts)
NOTE: In case the link doesn't work properly, start when you find the YT clips of Duck's SD40-2's, and statr reading from there...

http://model-railroad-hobbyist.com/node/15636?page=3

I'll be very interested to see what results a _proper_audio_test_procedure_ reveals...

Happy Modelling,
Aim to Improve,
Prof Klyzlr

Sound deadening roadbed materials

Model Railroader's special issue How To Build Realistic Reliable Track (2009) has an article on “quiet roadbed”.

The article reports on experiments with various HO roadbed materials installed on ½” plywood.  The quietest configuration was cork installed on 3/16” thick “camper tape”, a fairly soft foam tape used as a weather seal when installing camper shells on pick up trucks.  18 configurations were tested, including Homasote, cork, foam tapes, WS Track-Bed, and others.  All configurations used ½” plywood subroadbed, and did not explore “foam” subroadbed as used in the building trades for insulation (pink, blue, etc.), which has a reputation for being noisy.

There are many variables for “sound control”.  First is your own personal preferences and expectations.  Some folks like the noise of track glued to thin plywood (noisy!), and others are looking for near silence (me).  As some have observed, even the acoustics of your room will be a factor.

The basic principles for noise control (vibration control) are isolation and damping.  The combination of cork and camper tape (all glued with flexible caulk) provide some of both isolation and damping.  The resulting noise attenuation is the best of the 18 configurations, but “silence” is still elusive.

Gluing ballast is one of many variables.  “Rubbery” glue would be preferred.  In my final step, I glue the track with DAP Alex Plus, and spread and tamp down ballast while the caulk is still wet.  When the caulk has cured, I vacuum away the excess ballast.  After six years, the caulk is still very flexible, and the sound characteristics have been stable.

Six years after installation, I am very pleased with my “cork on camper tape”.  The softness of the camper tape has not been a problem, and seems to be some advantage in absorbing the expansion and contraction of rails and benchwork with temperature and humidity changes. 

Have fun!

Bob Kingsnorth

sound deadoning

I have used that pink foam that is about 1/8' thick and wider than the ballasted roadbed.  Then I have used cork roadbed, but this time I will be using WS foam roadbed.  I use pink or blue foam board on top of 5mm luan plywood over steel framework.

Jim

Ceiling Tiles Vs. Homasote Vs. WS Foam

When I constructed my 23 x 32 around the walls shelf/peninsula style HO model of a division of Conrail, I was moving into my freshly built home when my employer decided to replace 30-40 ceiling tiles from the drop down ceiling at work. So I was happy to take the best 12 pieces off their hands. Once turned over, nobody cares what they look like, especially after scenery is added.

In the photo included below, you can see near the throat of the yard entrance where the ceiling tile panels (supported by 1/2 OSB) have my quasi-handlaid track on Tru-Scale pine roadbed leading into the yard ladder where Elmer's brand Gator board (from Hobby Lobby) painted flat grime supports the Atlas code 83 yard tracks for 2 x 9 ft.. The back furthermost track on the far lefthand side leads off of the ceiling tile on WS Foam atop cedar shims until the foam is eventually direct on top of the 1/2" OSB plywood, until that track arrives at the chemical refinery plant shown in next photos.

All this works very well and deadens the sound levels to a whisper. The challenge I have is with keeping spikes to hold tight in the tiles, especially after respiking numerous times to alter an alignment or track arrangement. Hence the reason you won't find me spiking direct onto the tiles, except at short industrial spur leads. And as noted by others, the edges of the tiles can crumble apart if bruised by carelessness. But the edges will all be shaved, trimmed, contoured, and sealed up and covered by putty or tile grout when I complete the scenery anyway.

Here we see where the industrial lead from the left side of the yard photo comes into the chemical refinery plant vicinity. The thing about WS foam is, you either must glue it, or you have to NAIL it with long nails. I staple gun the foam down and use 1/2" long nails on the track, since I prefer to avoid having things set in stone without a chance to align, adjust, or change as necessary for operation. The dead end spotting tracks for the plant are to the left. (Photo 3 below)

 

This is where sound deadening will not be required, nor will the rails need to be elevated above grade much if at all. Besides all the tedious piping I have left to do on the refinery, I have only minor gaps in the roadbed to fill in with putty or caulk before I ballast over everything with a quick layer of dirty cinders and then fine gravel.

I will next show some more examples of homasote used on my layout

~Happy Modeling !

Bill March