Originally Posted by bdrex28
could someone explain about 4ohm and 8ohm for a newb like myself?
why is it so important on this system if it can do 4 ohm?
It's all part of the wpc measurement. There is no standard, so everyone does what they want. 100 wpc could mean that the amplifier can drive 100 watts into one channel at any one time. That does not mean it can drive 100 watts into all five or seven channels at the same time. Onkyo usually measure two channels driven (at least they are honest, and state that clearly in their specifications). Harman/kardon usually measure all channels driven (so their claimed wpc are always lower, but probably also more honest).
One of the issues with 4 ohms, is that an amplifier rated at 100 wpc at 8 ohms, might theoretically require 200 wpc (over simplification obvioulsy) to get the same volume with a 4 ohm speaker. This could cause overheating and send the amplifier into "protect" mode to avoid damage. The Samsung is a digital receiver, so the heat issues are not the same as with traditional receivers and they are rating it for 4 ohms anyway. Generally speaking, HTiBs are sometimes accused of measuring power at 4 ohms so that they can double (more or less) the wpc rating (I don't know how true this is or what the limitations of that accusation are).
So, what will be powerful enough? Well, generally speaking, 35 wpc is sometimes cited as "enough to play very loud". More watts beyond that may be useless anyway.
I haven't yet found any other authoritative sources that explain this more clearly in plain language than those already shown.