Originally Posted by mach250
[B]... am I thinking too much about this? ...
Almost. There's one thing you need to add...
Look up your speaker specs for "sensitivity." For example, the 8000's are rated: 98dB @ 2.83V / 1m.
- 98 dB is the SPL
- @ are test conditions
- 2.83v yields 1W @ 8 ohms, and more at lower impedance (power = V^2/R).
- 1m is a 1 meter listening distance, which follows the inverse square law so at 2m, SPL is 1/4 the level.
Now, figure out the SPL at, say, 100W.
- 2x power is +3dB
- 4x the power is +6dB
- 10x power is +10dB
- 100x power is +20dB
- Your 8-ohm 8000's are rated for 118dB @ 100W, 1m
- I sit about 2m away from my speakers, so 100W delivers 112dB from each speaker.
But you have 5 speakers, each with its own amp...
- +3dB for each 2x speaker cone area
- +3dB for each 2x amp power.
- a low estimate (based on 4) speakers is two doublings of each, +12dB
That gives you an SPL well north of 124dB at your seat, from only 100W. You'd make THX with 10W.
Any AVR can deliver 10W/channel, and the only reasonable amp candidates are the XPA-9 and -11. Those speakers don't need a lot of power unless you have a really large space to fill, and then there are better options.
Conversely, if you have 88-90dB sensitivity speakers, you need 100W to tickle THX levels at 2m listening distance from 5 speakers. That's why there's an XPA-5 Gen 2 sitting under my kitchen table.