Axiom Home Page Forums General Discussion Home Theater QS8 owners what is your crossover set at?

In reply to:

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What I was trying to find out is, if a QS8 would work well as a back channel speaker. The QS8 has a 180 degree dispersion and would cover a wide area so would one work instead of two.

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My Rear Centre is a QS4 (same as my surrounds) and it does very well. I have tried an M22 back there (tested out a bunch of different M3/M22 configurations this spring when I had the opportunity) and it was -- odd. I could go into a bunch of adjectives here, but I think that covers it, even when calibrated, there was wrap-around audio around me from the surrounds and HEY, LISTEN IT'S RAINING BACK HERE from the M22. Too bad, really - a direct radiator would have been cheaper. Standard disclaimers apply - I prefer the enveloping sound of diffuse surrounds, my listening position does not have much room behind it, since it was a speaker I knew I had just installed, my brain was actively listening to it, your mileage may vary, etc...

Bren R.

My previous 7.2 system used 2x M2s in the back surround position (FMB aimed down a few degrees) 2xQS8s in the side surround positions, and a pair of M60 like Michaura M665s up front (2 subs, SVS 20-39 and a Velodyne CHT10), heavily modded Merak center (2x6.5" axiom drivers and a horn). It all sounded pretty good, but the M2s in the back position were a step down in sound quality (HT) from the pair of Mission 77ds speakers I used before - it could be the M2s didn't like the high position as much as the Missions, dunno.

Great thread. Very informative.

ok, thnx bridman, i think i finally understand, i guess ill start fooling around one i get my full system...i dont even have a spl meter yet...

That's the only way to really learn. Fool around with the settings for a while... when you're good and confused ask some questions here... then fool around with the settings some more and repeat for a while.

That's how I learned. I imagine that's how most of us learned...

Legairre, on your opening question, although a 90Hz crossover might be more nearly ideal for QS8s, since the crossover isn't a sharp cutoff no "hole" is really created with the 80Hz setting and several owners use it with satisfaction.

As to using a single QS8 for a back surround, note that although there's no such thing as a 7.1 format(at most there's matrixed or discrete 6th channel material from DD and DTS), Dolby, THX, etc. recommend that the mono 6th channel material be reproduced with two separated rear speakers. The primary reason is a psychoacoustic reversal effect in which a sound coming from one speaker directly behind a listener will instead appear to come from directly in front of him. It's been suggested that with a speaker such as the QS which has a very wide dispersion this effect is less likely to occur. A second possible basis for using two rear surrounds is that when 2-6 channel material is processed with DPLIIx, Logic 7, etc. into seven speaker material the 6th and 7th speakers often receive different information and they should be separated widely enough so that listeners get both a left rear and right rear effect.

Thanks John,
I assume the hole is less likely to occur due to the QS8 trailing of to -9dB@65Hz. As for using the QS8 as a center back, I've always used two center back speakers to counter the psychoacoustic effect. I've tried it with one and it's always seemed like the sounds where coming from the front center channel just as you described.

You and BrenR both answered the one or two QS8 question. I assumed that due to the dispertion of the QS8 only one center back would be necessary, but like you said DPLIIx can seperate the 6th and 7th channel. My room works really well with two direct radiating back speakers, but I think two QS8 may be a bit much in a room thats 13' wide.