Confusing, isn't it? I'm not sure if I can help much here, but I'll give it a shot.

First, 6.1 / 7.1 / 8 channels and discrete/matrix... If you see 8 channel somewhere, they are probably referring to 7.1 (seven full-range speakers and one ".1" subwoofer channel). If you see 6.1 discrete, they mean that they've added a surround back channel (like the center surround that the Outlaw Model 1050 receiver has) that has a discrete signal (not extracted from the regular surround channels) -- this requires software support, and is basically limited to DTS-ES Discrete. The other 6.1 and 7.1 surround modes are "matrixed" -- it's like the old Dolby Pro-Logic days, where you took the left and right channels and "hid" center and surround channels in the recording, only now they "hide" a surround back channel in the left and right surround channels. Also, most "7.1" material is sending the same signal to both the surround back speakers (channels #6 and 7, let's say). Lastly, the ".1" subwoofer channel is amplified at the subwoofer typically.

With that garbage aside (and it is sort of messy these days), let's get to the nitty-gritty of receivers and pre/pros. The Harman/Kardon AVR-8000 you refer to is not a pre/pro, it is a receiver -- it has an amplifier built-in. It seems rather weird, but it is only a five-channel amp, so you'll need a separate amp to drive surround back speakers. The Pioneer VSX-49TX is also a receiver, and it has a 7-channel amp built in (no need for the separate amp for the surround back speakers). None are "8 channel" because of the fact that the sub is assumed to have its own amp built in. A receiver will list "channels driven" to indicate how many channels of amplification are built in. Each speaker you have will need to have its own channel of amplification.

The Outlaw Model 950 does not list any "channels driven" or any rating of watts per channel because it is a true pre/pro only, not a receiver. A pre/pro contains no amplification at all. It must be connected to separate amplifier(s).

Connections? Hoo-boy. Try skimming through here , specifically the "receiver and pre-amp" and "cables" sections. Basically, though, speakers are connected to the output of an amp of some sort (either a separate amp or the amp section of a receiver); the connections won't show up on a list of inputs and outputs for a receiver because they are covered by the number of amplification channels.

I think I probably just created more questions than I gave answers, but it's a start, hopefully.

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Gonk