How much weight can an upstair room can hold?

1 crack is not a problem. Cracks happen throu out the life of a house. They happen as the house settles. Watch the crack and see if it gets longer and you could also have someone come and look at it. No reason to get rid of anything.

Hevac1 is correct. one thing you can do is use some tape to mark the ends of the crack to see if it is elongating. Elizabeth is correct about storage of LPs, but 500 lbs of gear should not be a problem at all. Also consider where the gear is located. If its arrayed against a load bearing wall and spread out so its over several joists, then the load on any one joist is small and transferred to the vertical load-bearing studs and plates that are designed to carry much bigger loads. If you are really worried about this, call an architect or structural engineer. Would be well worth a couple of hours of their time (if they charge you at all; they may be able to answer this question very quickly in a brief phone call) considering the cost and hassle of selling all your gear.

Andrewdoan

I am a carpenter, general contractor and builder of all things great and small for my entire life.

A 10 year old house following the standard building codes would allow for 40 pounds per square foot of live load for your floor. Taking 1 room of 14 x 16 with a total of 224 square feet x 40 = 8,960 pounds equally distrubited throughout the room. A 300 pound refrigerator of 33" x 36 " = 36 pounds per square foot. These days lots of folks weigh in excess of 300 lbs. and occupy 1 square foot. I have never heard of someone falling through a floor or colapsing a floor. These loads a very conservative

You have absolutely no worries for your stereo or anything else in your home.

The crack is probably a drywall seam.

Enjoy your system and stop worrying.

Leatherneck 1812, thank you for the assurance . Now I have something to show to ther other half that the crack on the garage ceiling does not come from my heavy gear located in the bedroom above. It's bad enough to be confined " out of sight" these black "boxes" in a small square feet room....

Andrew- If the crack is in your garage ceiling and the garaage is unheated, its probably a thermal expansion/contraction thing, esp w a heated/cooled room above.