Soundproofing Adjoining Walls in a Townhome

Here is a generic listing of downloadable documents available from the NRC on Isolation methods. The NRC is an excellent source of tested construction methods. Pay particular attention to the doc regarding flanking paths.

You must first determine exactly how much isolation you require: (max internal level in db SPL - maximum external level in dB SPL) = minimum amount of isolation required.

Match the document and system to your particular construction.

And remember, there are NO shortcuts. The effectiveness is limited to the weakest factor. You can have the most elaborate process installed, but it is wasted if ANY of the other transmission paths are not equal in quality. In other words, the transmission level will be that of the weakest element.

Owens Corning Acoustical Wall Insulation Design Guide
(http://www.owenscorning.com/worldwid...a/30011340.pdf)

NRC (National Research Council) docs (Choose the docs that are appropriate to the construction type):

Gypsum Board Walls: Transmission Loss Data
By Halliwell, R.E.; Nightingale, T.R.T.; Warnock, A.C.C.; Birta, J.A.
http://www.nrc-cnrc.gc.ca/obj/irc/do...r761/ir761.pdf

Sound Transmission Loss Through Concrete and Concrete Masonry Walls
by Albert Litvin and Harold W. Belliston
http://www.cement.org/bookstore/prof...p?itemid=RD066

Sound Transmission Loss of Masonry Walls
by Warnock and Monk
http://www.nrc-cnrc.gc.ca/obj/irc/do...217/brn217.pdf

Sound Transmission Loss Through Drywall and Block Walls
by Warnock
http://www.nrc-cnrc.gc.ca/obj/irc/do...r586/ir586.pdf


Flanking information:

Controlling Interoffice Sound Transmission Through a Suspended Ceiling
by R.E. Halliwell and J.D. Quirt
http://www.nrc-cnrc.gc.ca/obj/irc/do.../nrcc33097.pdf

System Details That Work (Leaks and Flanking)
by David Quirt
http://www.nrc-cnrc.gc.ca/obj/irc/do...s-flanking.pdf

Guide for flanking sound transmission in wood framed construction - airborne sources
by Nightingale, T.; Quirt, J. D.; King, F.
http://www.nrc-cnrc.gc.ca/obj/irc/do.../nrcc49468.pdf

Airborne Sound Insulation in Multi-Family Buildings
by J.D. Quirt and T.R.T. Nightingale
http://www.nrc-cnrc.gc.ca/obj/irc/doc/ctu-n66_eng.pdf

Something like the Auralex Subdude can help decouple your subwoofer from the floor
http://www.auralex.com/sound_isolati...de/subdude.asp

The short answer is, unfortunately, no.

And quite frankly it is an issue best addressed in the initial design and build.
...Not something that you want to hear.

Isolation is one of the most difficult issues to address, and None of the solutions are trivial, nor will buying any 'nifty' consumer oriented device(s) solve the problem - regardless of marketing hype.

The answer is a 'systems' based solution that addresses the complete interface, requiring an attention to all mechanical and airborne transmission paths. The failure to address any one will render the system limited of the effectiveness of the least capable transmission vector.

So just know this before you spend money on an incomplete 'solution'.
It is possible, but it is not a trivial solution.

I apologize if I sound like the vice of doom here, but you should know what you are getting into here. And beware of any 'simple' fixes, regardless of what the marketing promises.

I would suggest reviewing the above docs after identifying the specific construction techniques utilized in your building. If you have access to blueprints from the builder, these can substantially aide your efforts.
Lacking this, it might even be worthwhile to get a qualified ME or expert in construction techniques to definitively identify the involved systems, as they may not be readily apparent from the inner surfaces.

As it is going to be a definite advantage to know precisely what you are dealing with in terms of the mechanical bridging, as well as determining EXACTLY how much isolation (SPL in terms of dB) you require. This will need to be quantified. And this will determine which options are applicable to achieving a solution.

You'll want an isolator as previously stated. It's important to note though, that these products reduce vibration, an important job, but don't really do anything to stop the low frequency waves your sub will be spewing. Vibrations are a big part of annoyance factor though, so you definitely won't want to ignore getting an isolator just because it isn't stopping sound.

Pretty much every company that sells acoustic products has some type of isolator for sale in varying levels of aesthetics and affordability. They're also fairly easy to build if you want a quick fix - just put MDF atop a few pieces of open-cell foam (the soft, squishy kind) that can support the sub's weight and voila!

Ok first off Green Glue isn't actually an adhesive. Rather it is a damping compound that gets applied between two solid surfaces and makes the process of sound energy being transformed to heat more efficient so that less sound goes through the wall. The drywall must still be screwed to the wall.

Quietrock is just two thinner pieces of drywall with a damping compound sandwiched between them at the factory to make one panel. A double drywall with green glue panel will be more effective due to the added mass of the drywall. It is also generally cheaper.

Take a loom at these articles:

http://www.soundproofingcompany.com/...r-noise-walls/

http://www.soundproofingcompany.com/...oise-ceilings/

As has been stated before soundproofing can be tricky and requires a good amount of planning.

I would suggest that you get in contact with Ted White, the AVS forum resident soundproofing guru, through a private message. He might even comment on this thread. Ted can give you great advice and help to ensure that you are on the right track.