# Proper use of PEQ for sub?



## Saturn94 (Jun 8, 2013)

I'm a newby to sub EQ and have recently learned how to take measurements using REW. The next step for me is to get a PEQ device and learn how to use it. I'm likely to get a miniDSP within the next month to use with my single sub, then possibly add more subs this year.

I came across a few posts that mentioned if you use too much cut or boost you will eat up the sub's available headroom. I'd certainly like to avoid that if possible. Is there a guide for newbies in the proper use of a PEQ? Any tips or suggestions are most welcome.


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## Saturn94 (Jun 8, 2013)

Anyone?


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## 86eldel68-deactivated (Nov 30, 2010)

This page has some good info: How to Use a Parametric Equalizer


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## Saturn94 (Jun 8, 2013)

eljay said:


> This page has some good info: How to Use a Parametric Equalizer


Thanks for the link. I'll check it out.


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## Phillips (Aug 12, 2011)

Would help to list sub, receiver and speakers, room size.

The reason is i have Velodyne DD15 in a medium size room and have heaps of headroom, not that i boost too much even with all this headroom.


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## Saturn94 (Jun 8, 2013)

Phillips said:


> Would help to list sub, receiver and speakers, room size.
> 
> The reason is i have Velodyne DD15 in a medium size room and have heaps of headroom, not that i boost too much even with all this headroom.


Sub: SVS 16-46PC+ (looking to add or replace with PSA sub(s) after I get a handle on using PEQ)
Processor: Anthem AVM20
L&R speakers: Soundfield Audio Monitor 1
Center and surrounds: NHT
Room volume: approx 5500 cubic ft (half the room is my living room/HT/Music area, the other half is the dining area)

Does this help?


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## Phillips (Aug 12, 2011)

> Processor: Anthem AVM20


Does the Processor do EQ or similar and have you tried this?

Do measurements without and with EQ to see difference, then look at the waterfall graph 0 - 300hz scale only, anything above 0 - 300hz (in the waterfall graph) has absolutely no use.



> Room volume: approx 5500 cubic ft (half the room is my living room/HT/Music area, the other half is the dining area)


Does the sub have alot of headroom e.g generally speaking the volume is 30%.

Have you found the best position for the sub and speakers, this is very important to save headroom + less eq?


> Does this help?


Yes crossover you use plus specs of speakers (mains only) and sub


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## Saturn94 (Jun 8, 2013)

Phillips said:


> Does the Processor do EQ or similar and have you tried this?
> 
> Do measurements without and with EQ to see difference, then look at the waterfall graph 0 - 300hz scale only, anything above 0 - 300hz (in the waterfall graph) has absolutely no use.
> 
> ...


The only EQ my processor has is a single PEQ filter for the sub (it's labeled Room Resonance Filter in the settings menu). There is no room correction or automatic setup feature. The PEQ filter is set at 73hz, 30hz Q, and -4db, to tame a bump there. I mainly did this to experiment with the PEQ filter as I've never used it before.

What am I looking for in the waterfall graph? I can post it here if you wish.

As far as the sub level, I'll have to double check where it's set when I get back from vacation. I'm pretty sure the gain on the sub is set fairly low and the sub level in the processor somewhere near 0.

I do have the L&R speakers placed for the best imagining and soundstage, and I tested the sub in the few possible locations available. Turns out the original location in the front left corner is the best. Again, I can post graphs if needed.

I let the processor handle bass management/crossover duties. After a bit of experimenting I got the best results setting the LP filter to 100hz and the HP filter to 75hz. Each channel, including the sub, is set to 75db using the processor's internal test tones and the SPL meter set to C weighting, slow response per instructions.

The L&R speakers are rated down into the high 30's I believe (it's a 3 way design with a coax mid/tweeter crossed over to an built in 8" powered "sub"). The sub is rated down to 16hz (it's native tune) and has a 525watt BASH amp built in.

Out of curiosity, I measured the output during the Darla Taps Aquarium scene in Finding Nemo with the processor's volume set to -3.5 and it hit 113.8db at the prime LP (Z weighting). It seemed the whole room was shaking!

Hope this additional info helps.


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## Phillips (Aug 12, 2011)

> What am I looking for in the waterfall graph? I can post it here if you wish.


Yes post the waterfall graph 15 - 300hz scale.

Also the frequency graph no smoothing required.



> As far as the sub level, I'll have to double check where it's set when I get back from vacation. I'm pretty sure the gain on the sub is set fairly low and the sub level in the processor somewhere near 0.


Check just as a quick reference. 



> I do have the L&R speakers placed for the best imagining and soundstage, and I tested the sub in the few possible locations available. Turns out the original location in the front left corner is the best. Again, I can post graphs if needed.


That would be good.



> I let the processor handle bass management/crossover duties. After a bit of experimenting I got the best results setting the LP filter to 100hz and the HP filter to 75hz. Each channel, including the sub, is set to 75db using the processor's internal test tones and the SPL meter set to C weighting, slow response per instructions.


You can see the balance with the mains and sub, phase, etc.



> The L&R speakers are rated down into the high 30's I believe (it's a 3 way design with a coax mid/tweeter crossed over to an built in 8" powered "sub"). The sub is rated down to 16hz (it's native tune) and has a 525watt BASH amp built in.


Size of the sub driver?
Crossover theoretically should be around the 70-80hz, basically 1 octave above your mains roll off.



> Out of curiosity, I measured the output during the Darla Taps Aquarium scene in Finding Nemo with the processor's volume set to -3.5 and it hit 113.8db at the prime LP (Z weighting). It seemed the whole room was shaking!


You are after SPL or accuracy?


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## Saturn94 (Jun 8, 2013)

Phillips said:


> Yes post the waterfall graph 15 - 300hz scale.
> 
> Also the frequency graph no smoothing required.
> 
> ...


I'll post graphs when i get back from vacation. Sorry, forgot to mention SVS sub driver is 12". Funny you mention crossing mains (high pass filter) at 70-80, 75 ended up the best. Also, setting the low pass filter to 100, therefore providing some overlap of the sub and mains, provided the best response.

SPL or accuracy? Both would be nice.


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## Saturn94 (Jun 8, 2013)

Phillips said:


> Yes post the waterfall graph 15 - 300hz scale.
> 
> Also the frequency graph no smoothing required.
> 
> ...


Sorry for the delay. It been crazy since returning to work (back to reality!).

I'm trying to post the graphs but its not working. I can post one graph, but not a second one. When I try to post the second graph it just posts the same graph twice.

Why won't it let me upload two different pics?

EDIT: OK, must be an IOs 6.xx problem.....pics posted OK on my Window Vista laptop, but not with my iPad Mini.


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## Saturn94 (Jun 8, 2013)

Phillips said:


> Yes post the waterfall graph 15 - 300hz scale.
> 
> Also the frequency graph no smoothing required.
> 
> ...


Let's try this again....

L+R+Sub, sub in left front corner:








L+R+Sub, waterfall








I also checked the sub gain position and my processor's sub level; gain knob on sub is at 9:00, processor sub level at +1.5


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