More than you all want to know I’m sure, but who else in the world would even care that I used to series-parallel wire four speakers off one amp channel to drive 8 speaker surround playback from a 5 channel input home theater amp? Only you all, maybe.
Not counting-
Currently unused stuff packed away (2 and 4 track recorders, old amps, disc players/burner DSPs, EQs, bunch of speakers, other odds and ends, the sweet rebuilt turntable I bought from Moke a several years back still sits packed in it’s armored cardboard box!.. my foot dragging, long story, thanks Mike!).
Stuff in current use which counts-
Sources-
Laptop S/P-DIF output via one of several USB boxes.
Recorder direct output from R-44 or DR-680 via S/P-DIF (2ch) or analog RCA (multichannel).
Silver discs via S/P-DIF from laptop drive or a couple component players (Sony, Panny).
Radio (analog terrestrial) via internal tuner in Panasonic receiver.
Which go through-
Mytek Stereo 96 DAC/headphone amp (thanks Audball)
-or-
Panasonic SA-XR55 receiver (S/P-DIF or 6ch RCA analog input, 7 amp channels, 100Wpc nominal)
and a Sony receiver for one additional amp channel.
Converted into sound again by-
Headphones-
Senn HD650 or Etymotic ER4S/P
-or-
Speakers (8 total around the room, no subs)-
4 x B&W 802 matrix v3 (Left/Center/Right/RearCenter*), 2 x B&W surrounds and 2 x Klipsh book shelves (model numbers of both escape me at the moment) as parallel wired Left/Right surrounds; Klipsh at ~90-110 degrees from center, B&Ws surrounds in dipole mode farther around the back at ~140 degrees approximately.
I re-patch input interconnects and speaker cables depending on the desired speaker configuration:
1) Direct 2ch stereo (the Panasonic self-configures with internal relays, bridging unused amp modules internally and biamping, providing 200Wpc to the woofers, 100Wpc to the tops nominal, probably not really)
2) 5 - 7ch matrix surround (un-bridged 7x100Wpc nominal, but not really)
3) Discrete 4, 5 or 6 channel surround (6 channel discrete uses the additional Sony receiver amp channel*).
Almost all of my 4 channel surround recordings are LRCB. Discrete 3 front channels to the Left/Right/Center speakers, with the single recorded Back channel mult’d and routed to all 5 surround speakers (the Klipsh’s at the sides, the B&W surrounds in dipole-mode farther back and the extra 802 which is the mate to the one used up front in the center, at the rear center).
My 5 channel surround recordings and movies or other commercial surround material looses the CenterBack 802, and splits the remaining 4 surround speakers into two parallel wired L/R pairs. If I had an easy way of matrixing a center rear from the discrete L/R surrounds I probably would, but the Panasonic can’t do that.
I’ve made a handful of 6 channel surround recordings which can be played by routing the (6th) CenterBack channel through the subwoofer input/output RCAs on the Panasonic so I achieve level and tone control over all six channels, which feeds one channel of the Sony receiver amp, which is used as a single amp channel only, its level knob set appropriately and then left untouched.
*The CenterBack B&W802 is the extra speaker of the second 802 pair, the other used as the Center speaker up front. It is amplified by the Sony receiver, which is all that receiver does. Believe it or not, I used to playback my discrete 4 channel surround recordings through all 8 speaker powered by the Panasonic alone. Using individual amp channels for each of the 802s (left, right, center, rear-center) and running the 4 remaining surround speakers off a single amp channel using series parallel wiring. It worked fine, but there is less patching required for 5 and 6 channel, more headroom, and although the series parallel load was not a problem, I still rest easier with the side surrounds simply paralleled and the Sony powering the Center Back 802.