Hi Audiofankj - in response to your question concerning the floor, IMO it would be most beneficial to double the floor joists, especially considering the fact that you use an analog source in your system. Without looking at the framing blueprints nor knowing what length of span is required, I would assume typical construction methods would entail using 2X10 joist lumber (and dependent on local building codes, the builder may be able to get away w/ using 2X8's). This, of course, is quite sufficient to carry normal second floor loads, but will still possess a certain amount of "flex". Again, doubling the joists will greatly strengthen the floor system, and while you're at it, spike the hell out of the doubled pairs (and to really get serious, lay some construction adhesive between the pairs before nailing) You are essentially forming "built-up" beams by doing all this labor. And timed right, you and some buddies could do this on a weekend (the contractor would need to know so as not to apply the decking before you got to it). As an aside, but probably prohibitive if working within a tight budget, is the availability of new types of trussed or plywood I-beam joist systems which could also be considered (you'd need to consult an architect on this subject).
Concerning the plywood, it pretty much depends on what the finished flooring will be, and how they typically do the work in your area. I would want a finished floor no less than one to one and a quarter inch minimum thickness. For example, if you go with a wood floor, this would equal approx. one and one-half inches finished. And, again, using construction adhesive on top of the joists before the subfloor plywood is layed will be of benefit.
Sorry - don't really know what level of experience/knowledge
you have with constuction techniques - kinda hard to know how to discuss here. If interested, just drop an email and we can discuss this ad nauseum. I was "complaining" to another AudiogoNer just recently that most of my forum participation is of the 'asking for help' variety, but this is one area that I can offer some suggestions. Regards ...Tom
Concerning the plywood, it pretty much depends on what the finished flooring will be, and how they typically do the work in your area. I would want a finished floor no less than one to one and a quarter inch minimum thickness. For example, if you go with a wood floor, this would equal approx. one and one-half inches finished. And, again, using construction adhesive on top of the joists before the subfloor plywood is layed will be of benefit.
Sorry - don't really know what level of experience/knowledge
you have with constuction techniques - kinda hard to know how to discuss here. If interested, just drop an email and we can discuss this ad nauseum. I was "complaining" to another AudiogoNer just recently that most of my forum participation is of the 'asking for help' variety, but this is one area that I can offer some suggestions. Regards ...Tom