I had down that receivers have built in amp vs pre/pro which have to have sep power.

Receivers.
Okay, so bing a total layperson I pick up the HK (seeing 7.1 on the box) and bring it home to my 7.1 speakers and unless the SP thinks to tells me, "By the way little lady you need another 2-channel amp with that setup". I just have 2 dead boxes (speakers) hanging on the wall. This unit will not "matrix" sound to 7.1 speakers as it sits because there is no power to run 2 of them. I think I've got it on (receivers) for a 7.1 system, watch out for # of amp channels on board vs preamps out. (Pioneer has it onboard for 7.1, HK does not as a standalone).

Decoders.
"Discreet" = separate channel information, no matrixing involved. (?)
Okay, if I look at just DECODERS, for 7.1 speaker setup. The most "Discreet" decoder out would be DTS ES 6.1 Discreet. It will send a separate signal to FL,FR,FC,BL,BR,BC and the LFE. And since I have basically (I'll call it) Back center L & R (the 6th/7th speakers) the ES 6.1 discrete will split the signal from the 6th channel equally into the 6th & 7th back L & R center speakers.
Any other decoder currently on the market has the equivalent of 5.1 Discreet channels and thus will matrix the 5th channel into the BL,BR,BCL,BCR equally?

Separates.
In a pre/pro only what connection (what is it called: do I need 8 of: (7 into amplifer/1 into LFE) indicates how many separate channels can be run out of that pre/pro into an amp. And if the pre/pro has 8 (whatever's) going out, then....
Your amp would nned to have 7 (what are they called?) ins if ONE amp is powering (what is it called) out to 7 speakers.
It's the what you ma call its, I need to know since manf (of separate components) seem to assume that if your samrt enough to buy separates, you know what the in/outs configarations are called; to see how many channels a particular unit is capable of processing/powering along the line?

In other words I seem to be lacking knowledge about the hardware side of pre/pros. Maybe I'm mixing up decoding/software capibilties with hardware. Is all channel handling done through the priopertory decoders, say if Lucas came out with THX SUPERKALAFRAGALISTIC (12 discrete channel sound), as long as the pre/pro had that decoder it could run 12 speakers? What would it need in HARDWARE on the ins/outs to run those 12 speakers? For me I trying to figure the hardware requirements of a pre/pro to run 7 channels?
(Shes circling the wagons but can't come in quite yet!)
Thanks for everything everyone and Thanks Gonk for the link I promise to read it 3 times till it sticks!