[Inscrutable]

I am starting from bare studs, and will soon be starting to finish the 'small' (500 sf) upstairs room, which will be an interim music/theater until I finish the 'large' (900 sf) theater room, but ultimately will be a listening room.  I really don't care about sound transmission into the rest of the house, since there won't be a lot of multi-tasking going on.  Similarly, I don't envision a lot of external noise existing which would migrate into the listening room.

It seems most/all the discussion involves sound attenuation to/from external areas, or add-on traps, absorbers, diffusors, etc added to already-finished rooms for internal reasons.  I am wondering if any floor/wall/ceiling construction directed toward soundproofing - resilient channels, double wall, visco-elastic damping, etc etc - provide any sonic benefit inside the room for stereo listening?

[warnerwh]

I doubt RC1 has any sonic benefits but is very inexpensive.  As far as room treatments go all I can say is they make a huge improvement in sound quality. Please go to realtraps.com and read about why. Also there's video there to show you how they can make a difference in sound. The only real test though is listening to your system in a good acoustical environment.

Bass traps and first reflection points are a must to get treated. For the little money this stuff costs it makes a very nice improvement in sound.

The peaks in dips that a room causes due to it's dimensions and furnishing are major. Peaks of 10db and dips of over 20 are typical. Imagine a child with a graphic equalizer randomly adjusting it for you. What your room does to the sound is actually worse!

After thirty five years in this hobby I've learned the first component to consider are the room acoustics if at all possible. Digital room correction can also help considerably but the bass traps, a minimum of 2, one in each corner, is mandatory to have decent bass at all. This actually causes the midrange clarity to improve. Please consider what I have said very seriously. Best wishes to you.

Another nice thing about having alot of room treatment is it helps to keep noise from outside down. This improves your s/n ratio and is quite noticeable.  You'll never be able to listen to a system in a bad room after experiencing what your system is capable of. Without treatments you system may cost 100k and still not sound that good. A 10k system in a good room can easily sound better than the 100k system in an average room.

Did I mention how important room acoustics are, they're huge!

[PhilNYC]

I had all the walls in my listening room stuffed with fiberglass insulation (R30?).  No real science used in the decision to do so, but I assumed that the "chambers" inside the walls could act as resonators, so putting insulation inside would help reduce that.  Don't have a before/after opinion, but the room sounds great (it also fully treated w/8th Nerve Adapt products)...

Part of the decision also came from the idea that in my old listening room, I used rigid fiberglass behind pieces of art-work at first reflection points with good results.  So even with a solid face in front of it, the fiberglass was doing something with regards to absorption...

[bpape]

The primary purpose for isolation in walls/floor/ceiling is to provide a lower overall noise floor in the room.  This allows for a greater sense of microdynamics and hearing all the tiny details - not to mention a greater overall potential dynamic range.  They'll do nothing for modal issues, decay time issues, early reflections, etc.

Things like RC-1, RSIC-1 and hat channel, etc. are primarily more useful when sound getting out is an issue and moreso at the bottom end of the spectrum - though they do help at higher frequencies.  If you choose to go this way, please avoid RC-1.  RC-1 is great for board rooms, schools, etc.  While pretty effective (not as good as RSIC-1), it is extremely unpredictable as to what it will do to the internal room acoustics.  It is extremely dependent on exactly how everything else in the room is done.  Distance between channels, between studs, screw spacing, etc. all will change it's absorbtive characteristics.  I avoid it like the plague in any music reproduction situation.

My recommendation would be to:
- At a minimum, scab a 2x2 to the bottom plate of the existing 2x4's and install additional 2x4 vertical studs staggered between the existing ones.  This will give you a good level of isolation across the board at minimal cost.
- As was stated above, fill the cavities with insulation.  No need for anything fancy - just make sure the cavity is completely filled.
- If the room is above any sleeping area or quiet reading area like a den or library, consider an isolation mat or green glue and a 2nd layer of subfloor.
- Double drywall can be used and provide additional isolation.  This will change the response in-room.  It will stiffen the wall structure causing the resonant frequency to fall and the amount of absorbtion normally provided in the upper base (centered around 125Hz extending say 1 octave each way) to be reduced by as much as 50%.

Bryan

[Ethan Winer]

I really don't care about sound transmission ... I am wondering if any floor/wall/ceiling construction directed toward soundproofing - resilient channels, double wall, visco-elastic damping, etc etc - provide any sonic benefit inside the room for stereo listening?

You already got good replies, and I'll add this: Sound isolation and sound quality (bass frequencies mostly) are competing goals. Construction that helps one harms the other. Massive rigid walls help to block sound, but they reflect more and to a lower frequency. So I always recommend against isolation unless it's really needed. You can have both, but it's more expensive and makes the room smaller and ceiling lower. But as Bryan pointed out, it's not only about noise getting out, but getting in too.

--Ethan

[Big Red Machine]

Lessons learned here:  I did not isolate my HT fromthe house and while I don't really regret it, it was not the brightest thing I ever did.  I did isolate my 2 channel room from the house as best I could w/o losing too much ceiling height by using iso max clips, hat channel, double drywall, green glue, and R19 in all the spaces.  Built a double wall with exterior insulated doors along the wall facing the hallway and furnace room.  I can set my stereo to 85 db inside and it will be 50 db outside both doors (when the furnace is off!).

Footfall from the hardwood floor above in the high traffic kitchen was my nemesis and while the best solution would have been separate ceiling joists I would have lost too much height and at 6'6" I need all I can get.  But I did use clips, double dw, GG, etc. and it is very acceptable.  I send out more noise than I get in.

So my lesson learned is it really pays off.

Room photos here:
http://alhull.com/room7/

The third photo shows both doors.  The walls actually do not touch each other and are double dw'd as well and the flanking noise that would go up and over the walls into the joists was slowed by lots of insulation, pink foam panels, and drywall cut to fit around all the pipes and ducts, etc, and then spray foamed in the cracks.  I've listened to Bryan and Ethan enough now to be dangerous!

[Inscrutable]

Thanks for the quick and insightful replies guys.  have to run now and will get back when i can make some better responses/discussion.  Again, I am not really concerned about noise from this room propogating outinto the rest of the house, nor really any from outside coming in - certainly not from inside the house.  and since there is a big window in the room, that is going to admit loud exterior noises regardless of the extra staggered stud/isolation I might do on the walls.  Later.

[Inscrutable]

And I was asking just about the isolation issues relative to perceived sound quality improvemnt and possible unintended consequences (as Ethan points out).  I fully subscribe to the need for room treatments, and had already planned to do fairly extensive work in that area.