# Pink Noise / System Setup



## xrmichael (Mar 26, 2010)

1st post so please go gentle if i have post in the wrong place.

I have had my system for a couple of years but due to work/family never had the time to tune it up to it's best, but the world recession has left me with some time on my hands.

The system is made up off:-

Yam Z9, Speakercraft MT81 for FLC, AIM81 for SL/SR, AIM8DT, for RL/RR, cinema sub 10 with accutune box for lfe.

After a bit if forum reading i started to setup/tune so on with the test tone (pink noise) and the first thing i have noticed is that the FL/FR do not out put the same frequency range as the C when looking at the analyzer in the room they are missing a lot of bottom and top. Looking at the Z9 settings all eq is off, is this a bad pair of speakers or is that how the FL/FR should perform ? i would have thought they would all be close on response.

Any ideas would be great.


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## torceador (Sep 8, 2010)

xrmichael,

Don't know if you checked this or not, but if the L/R are out of phase, they will display the curve you are decribing, depending upon microphone placement. That would be the first thing to check.

Carl


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## deang (May 18, 2006)

xrmichael said:


> 1st post so please go gentle if i have post in the wrong place.
> 
> I have had my system for a couple of years but due to work/family never had the time to tune it up to it's best, but the world recession has left me with some time on my hands.
> 
> ...


There could be several things causing your problem. As little more information about your equipment and room would be helpful before we jump to conclusions (I'll jump anyway). What are you using as pink noise, the processor/receiver or something like RoomEqWizard. You may also want to give us a quick sketch of the room and a list of the speakers.

I assume you are testing each speaker independently. You need to compare the LF and RF responses separately with the LF + RF responses. 

You can tell phasing if you test each speaker separately and then test pairs of speakers. Pairs of speakers out of phase with show dramatically different frequency responses than each tested independently (usually low frequencies roll off fast). And trust your ears, out of phase speakers played in pairs sound odd and lack bass while speakers pairs in phase sound fuller in lower frequencies. 

It's not unusual for the center to be significantly different than the right and left speakers. Often it's in a location that puts it closer to walls and the floor and sometimes the center speaker doesn't use the same drivers (can actually sound like a different brand of speaker, timbre differences). 

The same issue (frequency response different) can occur between the left and right speakers there is some non-symmetry around the speaker or your seating area like one speaker is in a corner and the other is next to an open hallway.


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## Wayne A. Pflughaupt (Apr 13, 2006)

Hi xrmichael,

What you’re seeing is perfectly normal. The only way the two speakers can have identical response is if the room is perfectly symmetrical. Even then, if the measurement mic isn’t perfectly centered between the two speakers, you can still get different readings.

Regards,
Wayne


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## xrmichael (Mar 26, 2010)

To update, the speakers are in phase checked and double checked, i will post a sketch of the room and also the rta trace of the 3 front speakers the fl and fr are too different from the center in my opinion for it to be room related the pink noise has been generated via the amp test tone to 1 speaker at a time and also a test DVD i made that plays pink noise in each speaker separately.


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