Phase issue, or what?

**savior sound** · **05-18-09, 03:49 PM**

Ok, after some changes to equipment and the room - furniture etc. I am trying to get back to getting some measurements in my dedicated HT. My first graph is sub alone (no eq & no mains) and then sub with BFD with two filters -3db @ 26.3Hz Q=10.5 and +8db @ 63Hz Q=10 the third one is when I turn the mains on which are crossed over @ 80Hz and my sub phase is 0. My question is this, should I try changing the phase on my sub to smooth out my results with sub+mains? My sub is adjustable in increments of 10 from 0-180. Or do I need to try changing my x-over point for my mains? Or both?

**brucek** · **05-18-09, 06:06 PM**

Quote:

My question is this

The first thing I'd do is remove the filter at 63Hz. Even disregarding that it's a gain filter (not a great idea), you're getting a bit close to the crossover to be adding a filter before you test the crossover area with the mains included.

I would certainly alter the phase of the sub to try and get a smoother response. It wouldn't be a good idea to change crossover frequencies to a frequency lower than the present 80Hz, as you would be encroaching on the sub even more with the mains. The sub alone is quite good. It's the mix with the mains that is causing trouble.

brucek

**savior sound** · **05-18-09, 06:12 PM**

Thanks, I will try the RTA feature you recommended to RonS1958 a few posts back and get back to you. So you think just the 3db cut filter is good?

**brucek** · **05-18-09, 06:18 PM**

Quote:

So you think just the 3db cut filter is good?

Well, a lot of people would die for that raw subwoofer plot.

So, if someone asked if they should add a BFD based on that plot, I would likely say no until you at least see what the sub/mains mix looks like.

But, if your filter comes from a sub with an integrated EQ in the amp, then the the -3dB filter would be fine.

Your sub + mains mix definitely needs work though. You may have to attempt some movement of the sub or mains or both. Sometimes, even a small move can help a lot. The dips are the concern. The peaks are easily EQ'd.

brucek

**Wayne A. Pflughaupt** · **05-19-09, 07:36 PM**

Can't recall where I've ever seen the sub's response so utterly destroyed when the mains were added. Are you sure your crossover is functioning - i.e., they aren't running full range?

Regards,
Wayne

**savior sound** · **05-19-09, 07:47 PM**

Yeah, I'm using AVR to do bass management with x-over set to 80Hz and x-over on sub off/LFE. I'm starting to think maybe I should try full band on the mains. That's what Audessey had it set to - my main towers have two 8" subs in each of them - but I manually changed it to 80Hz before running REW.

**savior sound** · **05-19-09, 07:51 PM**

Quote:

brucek wrote:

But, if your filter comes from a sub with an integrated EQ in the amp, then the the -3dB filter would be fine.
brucek

Only EQ this sub has are the depth, punch and flat settings. The filter I am applying is via BFD.

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