# Confused about sub phase control knob!



## wil11o6 (Jun 24, 2010)

As far as I know, from reading online is that the switch from 0-180 is to put it in phase or in-sync with your main speakers. If it is out of phase, the drivers will move in opposite directions and will cancel each others bass so I would hear less bass if it is not in phase.

Using my radio shack SPL meter in my listening area, I am running back and forth turning the KNOB from 0-180 while listening to test tones. Here is what I am confused about.

*@80hz I first set my mains at 75db, then set my sub to 75db to make sure they are balanced. I then play them both together.

0=80db
180=70db
90=68db*

So I thought that it should be set at 0 degrees since it yielded a bass boost whereas 180 and the 12oclock on the knob gave me less.

*@60hz is where I get confused :dontknow: I first set my mains at 75db, then set my sub to 75db to make sure they are balanced. I then play them both together.

0=64
180=80
90=75
*
What gives? Am I doing something wrong? at 80hz I get more bass at 0 degrees and at 60hz I get more at 180 degrees. Shouldn't it be consistent?


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## Floridapoolboy (Jan 27, 2011)

Ideally you should use the sub test signal from your receiver, and not individual frequency tones. Individual tones can give conflicting results, the sub test signal with its multiple frequency makeup should allow easy positioning of the phase control.


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## Sonnie (Apr 11, 2006)

If you have Audyssey, it will correct for phase. If not, use pink noise and set the sub phase to where it sounds the loudest, or measures the loudest. If you don't have pink noise, use the 80Hz tone for the phase setting, assuming your sub is crossed over at 80Hz. If you are using a higher or lower xover point, use the frequency closest to the xover point and test the various phase settings for the highest SPL.


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## nezff (Jan 9, 2011)

I would leave me knob at 0


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## koyaan (Mar 2, 2010)

Depending on the room, phase in a sub may not have a huge impact, though one setting is generally better than another. If your running some sort of set-up or room correction, the pre/AVR may already be settinmg the phase. 
With your resolts, I'd stick with 0.:huh:


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## bambino (Feb 21, 2010)

I would also stick with 0 and let Audyssey do it's thing. I have always left mine at 0 no matter the location of the sub.:T


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## wil11o6 (Jun 24, 2010)

It's hooked up to a budget receiver without Audyssey.


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## bambino (Feb 21, 2010)

bambino said:


> I would also stick with 0 and let Audyssey do it's thing. I have always left mine at 0 no matter the location of the sub.:T


Even without Audyssey. If i were in your shoes i would put it where it sounds best to you.:T


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## gdstupak (Jul 13, 2010)

I can't really tell you what to do, other than experiment and try to find what sounds best overall.

But your results are normal, just because your speakers might be in phase at 80hz, doesn't mean they will be in phase at all other frequencies. 

I balanced my system with outboard eq's. My main speakers have an eq, and each of my subs has their own eq. My main L/R speakers are set at full range, and they integrate evenly with the 2 outboard subs.

Without outboard eq's, I would probably limit the frequency range where the mains and sub play together. Set the crossover for the sub and mains at 80hz. This way you set the phase control so your mains and sub play together best at 80hz. Then when there is content around 60hz, the sub will mostly play that and the mains will not be interfering.


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