# Sub graph good alone but not with mains



## savior sound (Nov 30, 2008)

I was able to get great results with only a few filters on my sub but when I add my main speakers, everything gets pretty messed up. I tried every x-over point and 50 Hz looked better than any other. I haven't changed any phase settings on sub yet. Is that what I need to try next? Here is my charts for comparison. The top one is sub alone with target and the bottom purple graph is the sub with L/R


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## thewire (Jun 28, 2007)

savior sound said:


> I was able to get great results with only a few filters on my sub but when I add my main speakers, everything gets pretty messed up. I tried every x-over point and 50 Hz looked better than any other. I haven't changed any phase settings on sub yet. Is that what I need to try next? Here is my charts for comparison. The top one is sub alone with target and the bottom purple graph is the sub with L/R


It looks like you have the input REW input volume set too low. You might be setting the level because some dips around 70Hz-80Hz making it appear as though it's an accurate reading near the crossover. You might check your mic also that it is set correctly. Something looks a miss, but looks like it's an input level problem maybe seemingly by the narrow dips.


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## savior sound (Nov 30, 2008)

thewire said:


> It looks like you have the input REW input volume set too low.


Input volume is 1.000 (max) and levels during the measurement are good - any higher and I'm too close to clipping. Readings are fine until I add my L/R speakers.


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## jtalden (Mar 12, 2009)

It is more conventional to measure L/SW and R/SW seperately rather than L/R/SW. Operating all 3 together results in a misleading interaction.


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## savior sound (Nov 30, 2008)

jtalden said:


> It is more conventional to measure L/SW and R/SW seperately ...


I will try that. Thanks. I found that part of my problem was that I inadvertantly turned off my EQ filters for sub+L/R measurement


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## gdstupak (Jul 13, 2010)

jtalden said:


> It is more conventional to measure L/SW and R/SW seperately rather than L/R/SW. Operating all 3 together results in a misleading interaction.


I've heard others say the same thing, so I'm not trying to be combative, just maybe someone can explain this to me.
How is it misleading to measure them together? Sure it's easier to get good looking results measuring separately, but how often do you only listen to the right channel, or only the left channel.
Yes, today's music and movies have dedicated signals for each speaker but in my experience most mid to low frequencies are played through the left and right channels together (along with the sub, depending how you have your system set up).
Because of this I have always measured and tuned my left/right/(2)subwoofers as a set.

Steve, I too have the same problem as you, and it takes me hours of fiddling with the eq and phase control knobs before I can get all 4 speakers to work together. But once they're working harmoniously, it's all worth it.


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## Tufelhundin (Jan 25, 2010)

concerning both fronts and sub...

I ran both fronts and sub with REW in the same 9 locations that I had ran my ASEQ and AVR "note: only lets me measure 8 positions" and this is the average of those 9 measurments......


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## jtalden (Mar 12, 2009)

Well, I see my comment was misleading. I don’t disagree that they all should work well together in the end even though my comment can easily be taken that way. 

I just think it is possible to arrive at smooth response in XO range given multiple speakers operating that are not individually smooth. 

So I believe that it is better to first adjust the SW to a target response and then adjust for each speaker/SW combination independently. If that is done the combination response will look good as well.

In my case FL,FR and CC speakers require significantly different EQ from 70Hz to 160 Hz to provide a smooth response with the SW because of the room placements (My XO is 100 Hz).

Oops, Sorry, It just dawned on me that I was assuming that the Mains are being EQ as well as the SW’s. Most here are probably not doing that so I have just confused the issue – never mind.

Thanks for setting the OP straight.


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## savior sound (Nov 30, 2008)

Ok, here is what I ended up with.

Sub only







and with L/R







I still have some dips (and a pretty good 70-80Hz peak) above my 60 Hz crossover that I cannot EQ. Any suggestions?


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## fusseli (May 1, 2007)

savior sound said:


> I still have some dips (and a pretty good 70-80Hz peak) above my 60 Hz crossover that I cannot EQ. Any suggestions?


have you tried a higher Xover so that your sub EQ can apply more smoothing? Also, having phase adjusted perfectly at the Xover point is critical to a good transition from the mains. Do you have variable 0-180deg phase control?


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## savior sound (Nov 30, 2008)

Yes, I have tried full range, 40, 50, 60, 70 and 80Hz x-over points and chose 60 Hz because it was the response that needed the least work. I have variable phase control on sub from 0-180 degrees in 10 degree increments.


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## fusseli (May 1, 2007)

savior sound said:


> Yes, I have tried full range, 40, 50, 60, 70 and 80Hz x-over points and chose 60 Hz because it was the response that needed the least work. I have variable phase control on sub from 0-180 degrees in 10 degree increments.


did you re-align phase for each different Xover point for the smoothest response? If not, your trials at those different cutoffs weren't showing the best possible result. I'd say redo the 80Hz point with phase perfectly adjusted, then maybe even try again with 100Hz. Putting the Xover as high as possible will give your EQ the most control and I'd think the smooth reponse is worth the associated "sacrifices." 100Hz isn't *that* high even for a big sub to play, but I guess it does depend on how yours actually sounds.

Also, I'm not shocked that full-range mains didn't produce good results. This is because that opens the door for the mains and sub coming in and out of phase at different frequencies rather than just @ the Xover point..


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## rmalak (Apr 10, 2010)

I had similar issues at the crossover point in my system. The thing that seemed to help besides crossover and phase is the distance value in the receiver setup. Adjusting that after I had the phase and crossover as close as possible made a big difference to the big dip then hump at the crossover point. I hope this helps you.


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## savior sound (Nov 30, 2008)

Thanks, I will try that. The one constant is the steep null at about 64 & 124 Hz. Here is a graph comparing the best (phase) results at 80 and 100 Hz x-over points. Both are with Audessey but no BFD filters engaged.


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## fusseli (May 1, 2007)

savior sound said:


> Thanks, I will try that. The one constant is the steep null at about 64 & 124 Hz. Here is a graph comparing the best (phase) results at 80 and 100 Hz x-over points. Both are with Audessey but no BFD filters engaged.


I'm guessing those nulls are related to your room and/or positioning of stuff in the room since they show up when you have the Xover above or below the ~60Hz one. The 100Hz point almost looks better :sneeky: Try and see what the BFD does with that!

Where's your reference level at in those two sweeps, and ya definately can see the difference in phasing with either slope point the way the two plots come in and out of the same shape. Gotta be positioning or something...


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## savior sound (Nov 30, 2008)

fusseli said:


> I'm guessing those nulls are related to your room and/or positioning of stuff in the room since they show up when you have the Xover above or below the ~60Hz one.


Yeah. I'm gonna try RTA and move the sub around a little to see if I can get rid of at least some of it... especially at 124 Hz.



fusseli said:


> Where's your reference level at in those two sweeps,


If you are referring to sweep level, -12 db FS


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## robbo266317 (Sep 22, 2008)

I think fusseli is right in saying they are room nodes. They are almost multiples ie 64 x 2 = 128


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## savior sound (Nov 30, 2008)

After changing to an x-over point of 100 Hz - which is hard to convince myself to do since Klipsch RF-82's are good down to around 30 Hz - changing my sub's phase to 130 degrees and adjusting my Onkyo sub distance setting to 1½' closer than Audessey MultEQ set it to, here's what I ended up with at my main listening position.







It's a pretty big dip at around 126 Hz but seems to be more visually noticeable in REW than audibly noticeable in the room. What do you think?


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## fusseli (May 1, 2007)

savior sound said:


> After changing to an x-over point of 100 Hz - which is hard to convince myself to do since Klipsch RF-82's are good down to around 30 Hz - changing my sub's phase to 130 degrees and adjusting my Onkyo sub distance setting to 1½' closer than Audessey MultEQ set it to, here's what I ended up with at my main listening position.
> 
> It's a pretty big dip at around 126 Hz but seems to be more visually noticeable in REW than audibly noticeable in the room. What do you think?


Looks pretty good to me, much better! The 126Hz sag was there on your prior sweeps also so unless you can force audessey to EQ that point it probably won't get any better.

Don't be concerned about cutting your mains up high although they extend low (my mains can do about the same haha). The advantages to doing what you're doing are:
1) you're getting a flatter in-room response!
2) assuming a capable sub, you're saving power bandwidth on your AVR by cutting the bass from the mains. i can gaurantee that while playing bassy music, you can now turn it up louder before distortion from your AVR clipping sets in.
3) you aren't sacrificing the higher sensitivity of big mains

Only good reason to have mains set to full-range and not HPF'd, in any situation, would be if you didn't have a sub.


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## savior sound (Nov 30, 2008)

rmalak said:


> I had similar issues at the crossover point in my system. The thing that seemed to help besides crossover and phase is the distance value in the receiver setup. Adjusting that after I had the phase and crossover as close as possible made a big difference to the big dip then hump at the crossover point. I hope this helps you.


Thanks, that did help some. Were you able to smooth things out better than I was? Or is this as good as it gets?


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## savior sound (Nov 30, 2008)

fusseli said:


> The 126Hz sag was there on your prior sweeps also so unless you can force audessey to EQ that point it probably won't get any better.


I wish I could _force_ Audessey to do something about it. I thought about re-running Audessey - with BFD filters on - but I'm worried that it would cause me to have to start all over again. Should I try it?


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## Sirbrine (Sep 27, 2009)

I keep reading about how much bass traps / broadband absorbers can even out room response by reducing both peaks and nulls. I'm currently trying to figure out how to add some room treatments for our combo living room / home theater / stereo room in an aesthetically pleasing way.


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## savior sound (Nov 30, 2008)

fusseli said:


> ... it probably won't get any better.


Well, I got it to respond a little better. Here's what I ended up with.







Here is a graph for comparison from what I had to now.







Now I think I'm done... for now.

Thanks for all the input guys.


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