Sub phase and placement?

[msrance]

Friends, could you just help me out with a few querries?
1. In my Integrated amp Yamaha AX-596 there is no dedicated subwoofer out. I was adviced to use the 'rec out' output port to connect the sub. Is this is the best way out or is there some better method?
2. My Sonodyne sub has a phase control toggle switch with two possible positions of 0 and 180 degrees. what and how do you choose between the two? whats the science behind this phase control?
3. What would be the best way to place a sub in a relatively small room for a 100w/c amp, specially when the room is a bit too furniture clutered and has a tendency to produce lingering boom in the music. I have a pair of sonodyne floorstanders and a sub?

[F1]

Q1. If there is pre amp output for L&R channels in your receiver, use it. If the rec out is the same as pre-amp output you also can use it. But I doubt that the rec out will increase the subwoofer volume as you adjust the main volume. Otherwise, run speaker cable to subwoofer then from subwoofer to front speakers. Experiment with these option and find wich one works better for you.

Q2. You sit down at your listening position and ask somebody to switch the phase back and forth while listening to music with constant bass level and pick one that give you fuller/ more satisfying bass. In some rooms the difference is very noticeable. Either 0 or 180 phase will cancell bass more due to bass interaction with main speaker. At 0 degree the driver move forward, and when you set at 180 the driver move backward instead of forward.

Q3. Normally corner is a good place to start. If you don't mind crawling around the room and you have longer cable to experiment, place your sub on your sofa (listening position) and start crawling while listening to music with constant bass. The location where you find the most pleasant bass while crawling is the best position of your subwoofer. If you find the subwoofer is too boomy, lowering down the subwoofer crossover may help. I set mine at around 65Hz. Set the sub crossover and sub volume such that the sub blend nicely with the main speaker. A good sub setting does not call attention to itself but it gives more bass weight to the main speakers, such that you don't notice that the sub is there but you're missing the bass when you turn it off.

Good luck!

[msrance]

Thanks for the helpful suggestions buddy. The preout port usage came in handy - though the crawling will take some will power !!