Thank you all for the excellent responses. I first need to clarify a bit more which will address much of your input. What I didn't expect was quite this degree of info. so let me add to my original post.
*The entire project was built with one ever-present mindset during the entire process: In order to keep the sound from getting out (I did not want anyone knowing music was playing inside) I was going to build the entire room like a fishtank....one with absolutely no leaks whatsoever, and this is exactly what I did.
* The detached garage was built in approximately 1946 using what appears to be a very solid 3/4" hardwood (don't know the type but it IS a HARD wood...) mounted onto 2"x4"@ 24" on center studs with diagonal cross-bracing between each stud. The roof is also this 3/4" wood. It all sits on some type of poured cement foundation. 10 years ago it was vinyl sided (as was the house) and I had a new roof put on when I began the re-modeling which included the removal of the previous roof tiles, repair/replacement of any questionable original wood, then the addition of fresh tar-paper and new roof shingles.
*Original interior LxWxH was 19'x13'5"x9'with the 9' @ center of a peaked roof, (sidewalls @7').
*The 4" studs are what forced me to use the R-13 @3.5" thick as compared to an R-19 or R-30 which were 6" thick,(it was actually R-16 I believe, as I'll explain in a minute).
* Wall insulation was a type of recycled cotton denim, it was either "Ultratouch" or a similar competing brand (can't remember at the moment) touted for its ease of use, all natural fibers, and superior noise suppression characteristics.I believe it was actually rated an R-16..,
* Acoustic Sciences Corp. "Wall Damp" strips were applied to each stud before 1/2" QuietRock 510 was screwed to them.
*The same ASC "Wall Damp" material was then applied onto the Quietrock ( called "Wall Damp Squares")before the standard 5/8" sheetrock was attached next, thus providing a thin "air barrier" between drywall sheets. This was done to both opposing 'long walls' (the 19's).A type of special "Quiet Seal" caulking was used around the entire perimeter of both walls, plus additional extra tubes of silicone caulking "For good measure" to ensure no sound leaks...
* The short walls (13') were done more extensively because I felt I could spare a little room length.. The aft wall had R-13 between studs, followed by 2 layers of 1/4" particle-board(I had a whole bunch of it laying around so I pressed it into the insulation and bent nails on both sides to hold it in place). Followed by 5/8" sheetrock. I then found a few rolls of tar paper and completely covered it with that. THEN I framed out a new 2"x4"@24" on center based interior wall which I screwed another layer of 5/8" sheetrock to on the OUTSIDE of it (What a job that was getting it all screwed together and raised up). Once that was up it was another application of regular Owens Corning R-13 insulation. Final interior sheetrock was another layer of 5/8" sheetrock. This makes for a total # of layers from the outside inward as: Vinyl Siding, 3/4" [original]outside wood, R-13, 1/2" of particle boards, 5/8" drywall, tarpaper, a 1/2" air-gap, 5/8" drywall, R-13, 5/8" drywall.
* The front garage door wall was replaced with a new garage door (insulated) and bolted into place. A 5/8" sheetrock was screwed to its inside face. 1/2" air-gap and a new interior 2"x4' @24" on center framed-out wall with[again] a layer of 5/8" sheetrock screwed to its OUTSIDE facing side. O.C. R-13 between studs. 2 layers of 1/4" each particle board (same as the other end), another 5/8" sheetrock, a layer of "Quiet Glue" (a competing product to the famous "Green Glue"), and then an interior layer of 1/2" "Quiet Rock 510" as the interior wall.
I guess the "weak link" in all this is the roof @ only R-13, covered by regular 5/8" drywall on 3/4" firring strips,but when I go outside with the music on LOUD... it certainly can't be heard if some of it is actually going up...
Wpines: if the winter really gets brutal and my 2 oil filled space heaters really can't keep up, those heating units might be a great choice as a retrofit. Thanks for the tip.
Hifitime: I'm not ready to run a gas line out just yet, but in the big picture if winters become consistently raw, it's also worth a look. I'm on Long Island and the proximity to the ocean keeps temps here a bit more moderated than inland so it's usually not as bad as other areas of the state.
Blindjim, thanks for all the thought... you're right that extremes should obviously be avoided and fortunately I don't think it will ever get too extreme... if the interior ever gets much less than 50 or so I'll be out there with both heaters getting it back to at least 60 (one unit can pretty much do that alone). Besides, it is nice not to wear a jacket while listening of course (I haven't had to yet). I have no concerns about power outages or restarts either...as I have paid A LOT of attention to the dedicated power I'm running out to it (but that would be another post).
Jea48: I'm sure you're right... oh well. Do you think the textured finish I added to the ceiling paint thickened things up a tiny bit to help??!?
Elwood: thanks for the thorough evaluation. I do have a hygrometer in my room [in addition to the thermometer] for monitoring humidity. It has been at the dry end of the normal zone (about 40%) ever since I first powered everything up (late October) and it is something I will absolutely be monitoring at all times, especially summer. I will resort to a window based A/C unit which I'll "pre-cool" the room with while equipment initially warms up (I usually give it all a solid 1/2 hr before listening), then take occasional listening breaks as needed to turn it back on for re-cooling... I don't need the noise of it during listening and I have 2 ceiling fans which are quiet enough for actual listening.
Peter_s: I don't think it really takes too much juice to heat it up from the low 50's to the low 60's with the portables... Maybe it really does?? I'll find out when my winter electric bills start coming in... uh-oh?? And you're right: if I do get another 'real' heating system, quiet IS a MUST.
Tpreaves: HVAC system was certainly in my mind during construction. I figured one of those wall mounted ductless systems could always be added later if absolutely necessary once I've been through a full year of hot and cold weather. I hate to admit that $$$ was a deciding factor in this department... a decent ductless unit with both heating and A/C would run between $1500-2500 and I thought the window A/C unit and a couple of space heaters was worth a shot for something like $300 total... Also, a dehumidifier if needed (though the A/C unit helps)I'll know by this time next year if I played it right or not.Thanks.
Magfan: Window is double pane, plus I bought some lexan from my local H.D. and cut it to fit the window. I added silicone around the edges and pre-drilled then screwed it to the perimeter of the window as an extra layer. Inside, just below the glass, I built a full width "Ledge", 5/8" deep, with matching window trim which I use to support 2 sheets of 3/8" drywall that are 'Quiet glued' and screwed together, then trimmed with a thin layer of O.C. insulation (against the actual window trim) then secured on top with a latch to keep it snug against the window area. This provides more soundproofing and a certain degree of insulation as well. (There are vertical blinds in between too). Only problem is I'll have to build another one for the summer with the window A/C unit cut out for it.Temps can see high 80's to low 90'sF in the summers here at times.
This was all very helpful and a big thanks to everyone. Any other input is always welcome and I promise never to make another post this long. Happy Lissn'n
