I am posting this to help out anyone who may be wondering how many surround speakers are necessary for their space. Note that my conclusions below are a result of my listening experiences within my environment. Results for you may differ. I've posted pictures so that you may compare my environment with yours.

Background on my environmnent

I have a 4,000 cubic foot, acoustically bright room with speaker distances as follows from my sweet spot that is located at the centre of my couch:

a) two side QS8s mounted about 11 feet away and slightly behind my sweet spot,
b) two rear QS8s mounted about 13 feet away from the sweet spot,
c) M80s and M150 8 feet away.

My Denon pumps about a half watt for music and a few watts for movies into my M80s during normal listening. All of my speakers are calibrated at 75dB with noise from my Denon using my SPL meter. My EP600 is set to 80dB.









Surround Experience

I have been extremely pleased with my system for DD & DTS. I've also been pleased with PLII and Neo but only for cable viewing and a small selection of music. I wanted to answer the following questions once and for all:

1. Are 4 QS8s over-kill for my space?

2. Can I improve my listening experience by varying the surround configuration?

Listening Set-up

I used the following selections:

1. DD Movie - King Kong,
2. DD Music - Eagles: Farewell Tour I,
3. DTS 6.1 Movie - Blade III,
4. PLII: M & Neo6:M - Oscar Peterson: We get Requests & Diana Krall: Love Scenes

I tried the following configurations:

1. Current physical configuration and settings,
2. Same as 1 but with rears off,
3. Current physical configuration with just rears on,
4. Rears wired to the amp as sides. I made sure to adjust the delay settings in my Denon for the longer rear distance.

Listening Results

The two charts below show the results in two different ways. The first chart is basically a summary of the second.





Conclusions for my environment

1. Four QS8s are not over-kill for my space as I need both pairs depending on what I listen to.

2. Movies and DPLII:M (and most likely DPLII:C) sound better with the sides off and rears on. DD (and most likely DTS) music sounds better with the sides on; rears are unnecessary. A "fuller" sound is experienced with the sides on.

Note that all four QS8s do not need to be on at once. This could very well be due to my bright acoustical environment. If your environment is more dead, you will most likely benefit from all four on at once.

Interesting results, Mojo. Thanks for taking the time to do that and post about it. Out of curiosity, are you still considering room treatments at all?

Hi Charles,

Thanks for reading. I am considering room treatments but I am battling my wife and fear of the unknown. Also, there are other projects around here that need to take priority over room treatments.

Oh, man, I always forget that there are other things to spend time and money on. Maybe I should get married so I can be distracted, too.

.........UPDATE............

I've been tweaking with my settings for PLII:M and have discovered that if I turn down my M80s and VP150 by 5dB and side surrounds by 3dB from reference, I get a very seamless surround effect. After countless hours of tweaking, I seem to be dialed in perfectly for PLII. Now I have to try to do the same with Neo6 and DD/DTS.

Here are my reference settings (75dB) and final settings for PLII:

FL...-2.5...-7.5
C.....0.0...-5.0
FR....2.5...-2.5
SR....7.0....4.0
SL....4.0....1.0
SBR...6.0....6.0
SBL...6.0....6.0

I'm suprised your left/right mains are so different. When calibrated to 75dB's my mains are left +2 and right +1.5.

Actually, I had to adjust the left and right mains by ear in order to centre the image. I believe this is caused by my room geometry. The left is bounded by the fireplace nearby. The boundary for the right (landing with the stairs going up) is further away. For whatever reason, the white noise/SPL meter doesn't discriminate against these boundaries and sets both speakers to within a half dB of each other.

I noticed this when I first got my system and thought that it was a problem with the 80s. But I eliminated that possibility by testing. Then I thought it was my ears because my wife heard a centered image and I didn't. We've now established that my ears are far better than average and my wife has some hearing loss.

I think having a hearing test is a parameter that often gets left out of the equation when trying to determine optimal calibration of an audio system. Something you don't often see mentioned in the forums. This is especially true with some of us, ahem, older listeners. I had my hearing tested, and it proved to be somewhat dimished in the midranges. I still calibrate according to what sounds good to me, but it just helps to keep things in perspective.

Sounds good. The small difference I have from left/right is most likely to the shorter wall on the right hand side. I can tell you also, that my imaging is dead on and most people would bet a 1,000 bucks that my center channel is on most of the time.

My Odyssey also came with a cool calibration CD with many test tones and other tools. There is one that is the sound of a cash register moving from outside left, left, center of Left/Center, Center, center of Right/Center, Right, Outside Right. This confirms the SPL settings, as well as best toe in position from the listening seat.

Yeah, my centre image is dead on too now that I adjusted the M80 levels by ear. I find that with most songs and DPLII, I prefer the centre off on lower volumes (about a half watt per side) and the centre on for higher volumes (believe it or not, there are times when I do crank it ).

What calibration CD are you referring to?

I'm experiencing withdrawal symptoms now so I'm off to my man-cave .

This is a special calibration cd that comes with all Odysseys, from Odyssey.

Why doesent this get stickied, its good info.

The only stickies are from Axiom.

What's a sticky?

Quote:

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What's a sticky?

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It’s a thread that is set to always display at the top of a forum or sub forum index so it appears even before any threads with new posts. The “Auditioning Axioms in Your Area” thread in the “Hearing Things” sub-forum is one.