Oh, BTW, friendly disagreement with your assertion that HT and Music should be treated differently. Some do, true, but Sound is SOUND! The acoustics of a room don't behave differently between a bass drum and an explosion.
My room is dual usage, but 90-95% music. My Subs were placed using the Crawl, and are asymmetrically placed on the side walls. I do have a small room, but the idea can be applied anywhere, pretty much. If you want to dig deeper into competing theories, there is the Welti/Devantier approach which focuses on pairs of Subs in regular positions (ie front wall, corner loading, 1/4 wall, opposing corners... etc...) and the Geddes approach.
I am a big fan of Geddes' technique which encourages strategic asymmetric placement of the subs and keeping them off the front wall.
If you have capable towers, and especially full range towers, then they are already emitting some LF content, even with an 80Hz XO. By finding the best places for the Subs in your room, you can have 3-5 LF sources that are all triggering different room modes and working in concert to level you LF performance in-room.
Have fun!
