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post #1 of 12 Old 09-29-2011, 08:11 AM - Thread Starter
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I am not at home right now, so I cannot post any graphs but last night I was playing with my mini dsp, and getting everything tuned in, when I noticed a MAJOR valley around 100 Hz, but no matter how much I try to put back in with the mini, it doesn't change. Ideas?

My first DIY project. A dual, dual opposed setup

www.avsforum.com/avs-vb/showthread.php?t=1345494
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post #2 of 12 Old 09-29-2011, 08:13 AM
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post #3 of 12 Old 09-29-2011, 08:14 AM
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Quote:
Originally Posted by notnyt View Post

room mode?

+1 got the same issue at about 90hz which is just about one of the worst places to have one, no way to crossover properly.

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post #4 of 12 Old 09-29-2011, 08:14 AM
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Must be a room null. Common frequency to have problems.

Is the mini eqing the subs only? Also, eq is tough to correct nulls. Likely to be related to your mains.

Edit, wow, some quick posters Oops.

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post #5 of 12 Old 09-29-2011, 08:18 AM
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yep integration with your mains could also be the culprit, try switching around your xover point and see if that changes anything. Have you double checked that all you speakers are in phase?

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post #6 of 12 Old 09-29-2011, 08:19 AM - Thread Starter
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so maybe have my mains crossover lower? so the subs and the mains overlap? I was thinking phase issues.. possible?

Wow Beast, you read my post before I posted...

I did try switching the polarity on the subs with the mini, that made it worse...

My first DIY project. A dual, dual opposed setup

www.avsforum.com/avs-vb/showthread.php?t=1345494
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post #7 of 12 Old 09-29-2011, 08:28 AM
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Quote:
Originally Posted by Audiophile34 View Post

so maybe have my mains crossover lower? so the subs and the mains overlap? I was thinking phase issues.. possible?

Wow Beast, you read my post before I posted...

I did try switching the polarity on the subs with the mini, that made it worse...

haha, I try my best

not necessarily overlap, just move the crossover point on both, either up or down, might help to alleviate the problem, but as tuxedo said, that area is pretty common for room modes as well. where are you crossed atm?

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post #8 of 12 Old 09-29-2011, 08:31 AM
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If changing the polarity didn't fix it then it could be the room mode. I would move the sub around to a number of spots, even if you can't place it there permanently to see if it changes.

I recently threw together 4 sealed MFWs and put them in front (2 left and 2 right) and was underwhelmed by them only to find that there was a terrible null at my left front corner. Moving the subs around fixed the issue.
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post #9 of 12 Old 09-29-2011, 08:36 AM
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I agree with beast, move the XO up and down and measure each time. See what that yields.

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post #10 of 12 Old 09-29-2011, 09:02 AM
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Post some details about your room and system. If it isn't a polarity issue then it is a modal issue only solved with altering subwoofer placement. You can also try moving the mic around if you can put your software in RTA mode and see if this issue is present in other places in the room.

My money is on it being a room mode issue best solved by multiple subwoofers.
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post #11 of 12 Old 09-29-2011, 10:13 AM
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also try delay ion MiniDSP or changing subwoofer distance setting

Noah
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post #12 of 12 Old 09-29-2011, 10:45 AM - Thread Starter
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I have two, dual opposed cabinets, one corner loaded, about 15' from lp, the other is right next to lp inbetween, couch and chair acting as an endtable. Mains are paradigms monitor 11.. avr is onkyo 876.

My first DIY project. A dual, dual opposed setup

www.avsforum.com/avs-vb/showthread.php?t=1345494
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