@jo1mtb i am also preparing to build a dedicated two channel listening room in my basement with 10 foot ceiling height. I have spent 3 months researching everything from room dimensions for least problematic room modes to optimized wall construction methods for noise isolation/best acoustical performance to best dedicated electrical service practices.
Here are a few suggestions to consider:
1) Room dimensions have a significant influence on room modes that will give you fits and require big investment in room treatments to try to reduce these “built in” problematic room modes. Bottom line is that a) square rooms are most undesirable, b) any dimension that is a direct multiple of any other creates overlapping axial modes (the most problematic type to treat), c) small changes in any dimension (even a few inches) can have a large effect on resulting room modes.
So, your proposed 15’ x 15’ x 10’ room size is really a big problem (violates a and b above). Even a 15’x 20’ x 10’ room would be a real problem with overlapping axial modes. One of the best ratios is 1.4 x 1.9 x 1. Given our fixed 10’ ceiling height, that would be a 14’ x 19’ x 10’ room. This is the room size I plan to build.
If you want to play with different room dimensions scenarios to see their resulting room mode behavior, try this tool (and also Bob Gold’s calculator):
2) After talking with several big name acoustic design companies, I have chosen ASC. Their technical folks are readily available for consultation (at no fee), are super helpful, and never try to push their products as the solution to every need. I also have concrete block walls on two sides on my planned room space. Their advice here was to build the framed walls at a least a few inches away from the concrete block to give air space for pressure to escape, also using insulation between studs and even plywood sheet on the outer side of the framing.
Since our master bedroom is directly above the planned listening room, sound isolation through the ceiling (both to and from he bedroom) is a major concern. After thoroughly investigating several options, I chose ASC’s ISO-Wall resilient channel system for the construction method for my room. Not only does ASC’s system provide excellent sound isolation, the resilient channel system allows the walls to act as controlled membranes to improve low bass room modes. You can get details on this system form their website or by calling ASC.
3) My conclusion on insulation was that the more expensive types (rock wool, etc) are a poor cost/benefit proposition over standard fiberglass insulation. It is the millions of small fibers with ample air space between them that perform the work on acoustic dampening, so loosely packed fiberglass insulation (R-13:or R-19) works great between the studs in your wall. Consider using 2” x 6”:lumber for wall studs in your construction - much stiffer than standard 2” x 4” studs ad only about 20% more expensive.
4) As for room acoustical treatment, that is a whole big enigma unto itself. Beware of companies that push “more is better” and “one size fits all” recommendations. Room size and construction have a great deal of impact on how much interior room treatments will be necessary. Poor decisions on room dimensions and construction techniques will cost you much more in subsequent interior room treatments to deal with the undesirable room modes and resonances that will result.
Hope this helps!