Anyone here tried turning a 6.1 setup into a pseudo 7.1 setup by wiring 2 back surrounds in series? My receiver is only a 6.1 (only powers 1 back surround output). Seeing that I have 2 speakers available for the back surrounds (so why waste 1 speaker), I am thinking of wiring the 2 in series at the back of my room. They will both be outputing the same signal, but perhaps having 2 at the back might improve the 360deg sound imaging (maybe not?).

Anyone tried it?

Amer, it's unnecessary to use the term "pseudo" because there's no "real" 7.1 format. Both DD EX and DTS-ES have a matrixed or discrete 6th channel, which is then reproduced by either one or two back surround speakers. It's generally agreed that two speakers do a somewhat better job with the 6th channel. As you see, the term "7.1" is something of a misnomer.

The two back speakers can be run off one amp by being connected to it either in parallel or in series. If 8ohm speakers were connected in parallel the resulting impedance would be 4ohms, which might be okay. In series, the impedance of the speakers would be doubled, but such a connection tends to result in some response variations, which might not be especially significant in a surround speaker. So, the only difference is that you'd be using one amp channel rather than two to drive the two rear surrounds.

Yes, I've tried it. Sounded good to me. I wired them in series, since that's supposedly safer with an amp not rated for 4ohm outputs (as my Kenwood VR-6070 is not). However, I've since moved from pseudo-7.1 to real 7.1, by connecting the two back surround pre-outs to an external amp (which is an old receiver).

These terms "pseudo 7.1" and "real 7.1" don't have a standard agreed on sense, but I think they are reasonable ways of describing the describing the difference between running two speakers off one receiver amp and having two independently controllable signals going to the two back surrounds. I think I am disagreeing with JohnK, here. With a real 7.1 setup, the distances and volumes for the back surrounds can be set separately, and, even though there is at most one discrete source channel being played, the two signals are decorrelated. Since my back surround speakers are in fact at different distances from my listening position, it's useful to me to be able to set their volumes and distances separately.

JohnK,

While you're certainly correct regarding the DD and DTS standards, many "7.1 receivers" use two seperate amplifiers for the rear channels and employ a DSP to pull positional audio into both rear speakers from the sixth channel and the two side channels. This is more than simply producing the rear channel through two speakers.

Amer, although what Greg and semi say about some 7 channel receivers applying special processing to the 6th channel so that the two rear-surround speakers wouldn't get exactly identical material is entirely correct, I'll stay with the point I proposed to you. Generally, when the special processing isn't applied, both rear surrounds get exactly the same information from the monaural 6th channel, which is as it was designed to be. Since the term "pseudo" indicates a simulation or fake of something real,and since no 7.1 format exists, the term "pseudo 7.1" is an oxymoron.

Although it's now a bit dated, you might be interested in reading the face-off between various surround configurations which these guys ran .

The Mike Wood article was interesting. Thanks for the reference. Did you notice that the speakers rolled off the highs more in dipole mode than when used as monopoles? I'd guess that would prejudice the comparison in favor of dipoles.

Thanks for all the info guys. Well I wired to speakers in series as the back surrounds. Seem to work just fine. They are direct radiating speakers though, one day I will try di-poles.

Yes, Greg, the rolled-off highs in the dipole are certainly to be noticed. In fact, for a somewhat iconoclastic take on the entire dipole question you might be interested in David Moran's article and letter on the Boston Audio Society site.

Also interesting, thank you. I've tried facing surrounds to the corner, but with no obvious good effect. But I don't have the means to adjust treble to maintain tonal balance. Something that has worked for me is hooking up extra speakers in series to the side surrounds. Pseudo-9.1.

Hey Semi,

Do you happen to know what receivers have the capability to do the positional 7.1 effect. YOu think the harman kardons do?

I believe the 8000 series, they're highest model does it. Beyond that, I haven't looked at them.

I wonder if that is the "Logic 7" mode they are talking about, if so then the 7200, 525, and 325 have it as well.