Need advice on how to sound insulate my room

Dtc is on the right track - to stop everything down to about 500Hz, another layer of drywall (preferably 5/8"), with copious amounts of Green Glue would be a good start. Sound is like light, and if you seal up your listening space, you can achieve decent attenuation. Lower frequencies are much more difficult - really the only way to stop them is with massive reconstruction. Mass and stiffening will only go so far (bass will pass through a 6" cinder block wall with no problem if the sound source is on the other side of it); what you need is acoustically dead space and that may not be attainable given your current situation. Good luck.

I'd recommend the book Premium Home Theater by Earl Geddes, and the concepts apply to stereo as well. I bought several books on the topic but found this one to be the most useful and an easier read. His approach addresses bass without dampening out higher frequency detail, which sounds like a concern of yours, and unlike most of the other books he recommends actual products which I found very helpful. Best of luck.

Have you tried de-coupling the speakers from the floor? had a similar problem and proper stands with Blu-tack helped quite a bit.

Thanks guys -- good suggestions all!

Ths, my rig sits on a carpeted concrete slab in the basement. Doubt that the carpeted slab will transmit that much sound to the rest of the house. As the above posts suggest, most of the sound is passing through the drywalls and ceiling to the rest of the house. I think the only way to attenuate the sound is by doubling up on the drywall as suggested, plus the Green Glue stuff.

Adding drywall and green glue (or liquid nails) may help with some of the problem, but the deeper bass will probably continue passing through the walls and travelling to the upstairs via studs, etc. You just can't practically add enough mass to attenuate those frequencies. If you're willing and able to do it you might look into resilient channels that act like shock absorbers between the drywall and studs, beams, etc. Again, the Geddes book I mentioned earlier does a good job of explaining this stuff.