impedance question


Hi I'm trying to understand ohm's and power. My b&k 200.5 is rated at 200 watts per channel at 8 ohms and 375 at 4 ohms. Now some of my speakers are rated 4 ohms and some are rated at 6 ohms. My question is does the amp just feed the power differently to each speaker accordingly? ie, 4 ohm speaker will receive 375 watts and the 6 ohm somewhere between 200-375?

2nd question is i had my sub woofer wired parrellel to my mains, everything seems to be working fine but I just read that I really put a load on my amp by dropping it to 2 ohm? is this correct? Is this a bad thing to do? I don't know how else to wire my sub because for some reason my rca sub output on my receiver doesn't seem to work. any suggestions?
monterey
1)Those power ratings are the MAXIMUM power capability that the amp is rated to CONTINUOUSLY deliver into the stated impedances. The actual power delivered is determined by the volume of the music at any instant of time, and will generally be far lower than those numbers.

2)No, that is not correct, assuming that the sub contains its own amplifier (as is usually the case). The input impedance of the amplifier within the sub will normally be vastly higher than the impedance of the main speakers, and therefore will present a negligible load to the main amplifier.

Regards,
-- Al
Also, the impedance rating of a speaker is its nominal rating; most speakers will have an impedance function, and associated phase angle (a function of the driver/cab design and crossover type), that vary widely across the operational bandwidth. And, most listening is performed at levels with the amp cranking out, again nominally, 1 watt or less.