In home theaters, is it advisable to use metal furrings as studs for double walls?

Specifically, metal furring such as “hat channel” for use as a “stud”? No. Metal framing, i.e., metal studs (or woods studs,) should be used to fabricate walls, never metal hat channel.

Properly installed metal framing (preferably not less than 20 gauge,) is very common and extremely versatile. Metal framing provides an excellent alternative to—and additional benefits beyond—that of wood construction. (By the way, 24-inch O.C. stud spacing contributes to a significant increase in overall sound transmission loss [TL], thus improving sound transmission class [STC] performance.)

There are a few basic methods to effective sound proofing and noise reduction: wall construction that is stiff and rigid or somewhat compliant, low mass or high mass (the latter being a much more popular approach.) The goal is to maximize wideband sound transmission loss through dissipation or attenuation of acoustical and mechanical energy through absorption and diffusion (or scattering.) Whichever approach one might employ, sound transmission loss can be greatly improved by utilizing a large sealed dead air space, often filled with fibrous insulation, within each of the room boundaries.

As I stated, it’s always beneficial to fully insulate the walls (and, when applicable, the ceiling) of a room that requires a higher degree of noise control, e.g., recording studios, commercial cinemas, home theaters, music listening rooms, etc. Insulation significantly helps decrease acoustical energy. One of the best materials for that purpose is acoustic fiberglass batt insulation.

In addition, if you choose to use metal framing be aware that flexible conduit is necessary for routing all of your A/V and structured cabling. Electrical wiring, in the form of non-metallic (NM) sheathed wire (aka Romex) or armored cabling such as metal clad (MC) or BX cable can be easily installed in steel framing members when using the proper insulating grommets fastened to the applicable punch-outs.

The bottom line: I highly recommend metal framing whenever possible, even for furring-out walls, combined with acoustic batt insulation installed between all the joists and studs.

######################## RESOURCES ########################

Dietrich Metal Framing

– Guide to Fire & Acoustic Data for Steel Floor & Wall Assemblies

http://www.dietrichindustries.com/library/library....

– An Introduction to Light Gauge Metal Framing

http://www.dietrichindustries.com/library/library....

[PDF] Steel Framing Alliance: Steel Trade Contractor Guide

http://www.steelframing.org/PDF/SFA_Trades_Guide_1...

Yahoo! Answers

– How much weight can a metal stud hold?

http://answers.yahoo.com/question/index?qid=200803...

– Building home theater in new home...?

http://answers.yahoo.com/question/index?qid=200804...

Audio, Video, Home Theaters and Acoustics

http://docs.google.com/View?id=dhpmqnbb_20f7j2qmhc

Owens Corning Acoustic Systems for Noise Control & Sound Quality

http://www.owenscorning.com/around/sound/acoustic....

Johns Manville

– Commercial and Residential Insulations

http://www.jm.com/insulation/5749.htm

– Commercial and Industrial Insulation FAQs

http://www.jm.com/insulation/faqs/69.htm

– Residential Insulation FAQs

http://www.jm.com/insulation/faqs/902.htm

– Are there advantages to using steel studs vs. wood studs?

http://www.jm.com/insulation/faqs/1002.htm

National Research Council Canada - Institute for Research in Construction

– Sound Transmission Through Building Components

http://www.nrc-cnrc.gc.ca/eng/ibp/irc/bsi/85-sound...

– [PDF] Airborne Sound Transmission Through Walls and Floors

Buildinghttp://www.nrc-cnrc.gc.ca/obj/irc/doc/sound-transm...

– [PDF] Controlling Sound Transmission into Buildings

http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/bpn/56_...

Yes you can, by using self drilling, self tapping metal fixings (sometimes called TEK fixings) which you should get from a good builders merchants, or at worst, from a roofing supplier (they're often used to tie the thin sheets of metal roofs together). They look like a normal screw (although they'll be quite a bit thicker), but they have a "drill bit" point on the sharp end the extends down the screw by about 5 mm. This means that they drill their way into the metal, then the screw follows the 5mm drill point and self taps its way into the hole created by said drill point - all in one nice easy step. You'll need to ensure that you buy fixings that are designed for thin metal - the thick metal ones have a longer drill point and a tighter thread, the thin metal ones have a shorter drill point and much wider thread. If you use these through the thing you want to hang (i.e., cupboard back, or whatever), through the plasterboard and through the metal, they will tie them all together and will hold quite an impressive load. Make sure you get fixings for steel, as if you get aluminium ones, the steel of the studs will react with the aluminium and the aluminium will rot to a fine white powder (not too good for strength !). The hardest thing you'll have to do is to find the metal studwork - you could use a "pipe finder" type instrument, which bleeps when you pass it over metal hidden behind a wall, unless you're very lucky and can see the plasterboard fixings, which will show you the stud line anyway. Good luck !

Yes it is mandatory if you want vibration you have to get those boxed speakers.