# EQ Dual subs



## Dwight Angus (Dec 17, 2007)

I am a complete newb to EQ. I want to EQ my dual SVS PB13 Ultras and not sure if I should eq them separately or together. I will be using REW to manage frequency changes with UMIK-1 calibrated mic. I have not yet purchased the EQ device just trying to educate myself at this stage.

I want to eq the average sub response across HT front row 3 seats. Should the average be comprised on 1 or both subs? 

My Preamp is Onkyo 5508 with 2 sub inputs.

Once subs are eq'd I will run audyssey xt32. I am assuming the EQ will be active when I run MULTEQ so Audyssey will detect the adjusted frequency response.


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## Wayne A. Pflughaupt (Apr 13, 2006)

EQ them together as if they were a single entity – after all, that is the way you hear them, right? :T You’ll drive yourself nuts trying to equalize them separately. You’ll probably find that you’ll get each one looking good separately, but then response will be whacked when you measure them both together. 

Regards,
Wayne


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## sdurani (Oct 28, 2010)

If both subs are going to get the same signal, then you should measure and EQ them together, just like you'll be listening to them. 

Since XT32 does this already, why not see if the EQ in your receiver will do the job before investing in a separate subwoofer EQ?


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## Dwight Angus (Dec 17, 2007)

Hi Wayne
I don't have the EQ device yet but if are you saying both subs are eq'd as one does that mean the EQ device will only have 1 sub connected to it? I was going to connect both subs to it.


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## tonyvdb (Sep 5, 2007)

I agree, given you have XT32 and sub EQ I dont see and real advantage to using anything down stream from that. Placement of the two subs will be the much more crucial item to play with.


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## Dwight Angus (Dec 17, 2007)

tonyvdb said:


> I agree, given you have XT32 and sub EQ I dont see and real advantage to using anything down stream from that. Placement of the two subs will be the much more crucial item to play with.


After allot of sub crawling I found the best HT placement. They are colocated mid screen wall. My issue is with frequencies below 15 hz. Sub eq doesn't handle this area very well and I find mid range frequencies are clouded with bass dominant frequencies. I adjusted the PB13 sub parametric (EQ 20 hz 6 db low Q cut filter) on the subs and that helped but requires more work.


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## tonyvdb (Sep 5, 2007)

Sounds like you need some bass traps in your room? That could very well be the very best investment at this time.


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## Dwight Angus (Dec 17, 2007)

tonyvdb said:


> Sounds like you need some bass traps in your room? That could very well be the very best investment at this time.


Bass traps are already installed. I need some tuned traps in the lower sub frequencies 30 hz and below. I checked with GIK and they estimated I would need approx 8 to 10 tuned Scopus traps. These are not cheap and I don't have the space to install them. You can see my sub response in the REW forum that shows lower frequency gain.


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## Dwight Angus (Dec 17, 2007)

sdurani said:


> If both subs are going to get the same signal, then you should measure and EQ them together, just like you'll be listening to them.
> 
> Since XT32 does this already, why not see if the EQ in your receiver will do the job before investing in a separate subwoofer EQ?


XT32 does a great job when I compare REW graphs with and without audyssey EQ, however it doesn't manage the lower sub frequencies very well 20 hz and below so I need some supplementary EQ to better manage low frequency gain


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## Wayne A. Pflughaupt (Apr 13, 2006)

Dwight Angus said:


> Hi Wayne
> I don't have the EQ device yet but if are you saying both subs are eq'd as one does that mean the EQ device will only have 1 sub connected to it? I was going to connect both subs to it.


Split the equalizer's output with a "y" connector and send it to both subs.

Regards,
Wayne


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## Dwight Angus (Dec 17, 2007)

Wayne A. Pflughaupt said:


> Split the equalizer's output with a "y" connector and send it to both subs.
> 
> Regards,
> Wayne


Many thanks


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## Dwight Angus (Dec 17, 2007)

Wayne A. Pflughaupt said:


> Split the equalizer's output with a "y" connector and send it to both subs.
> 
> Regards,
> Wayne


Alternatively could I "y" connect both subs and treat them as one so one sub input to eq device and one sub out?


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## Wayne A. Pflughaupt (Apr 13, 2006)

Not really following that, but any method you use to split the signal _after_ the equalizer will work.

Regards.
Wayne


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## Dwight Angus (Dec 17, 2007)

Wayne A. Pflughaupt said:


> Not really following that, but any method you use to split the signal _after_ the equalizer will work.
> 
> Regards.
> Wayne


So 2 subs input to EQ and 1 sub out from EQ output then Y connect to split signal to both subs. Is my understanding correct?


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## Phillips (Aug 12, 2011)

Easier to Y adaptor at the receiver end i would think?


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## Wayne A. Pflughaupt (Apr 13, 2006)

Receiver sub output -> EQ input
EQ output -> “y” cable to both subs.

Regards, 
Wayne


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## Dwight Angus (Dec 17, 2007)

One final question. 

Do I run Audyssey xt32 MultEQ setup before or after running parametric EQ? Not sure if the parametric EQ works on raw room response or response results with Audyssey included.


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## Dwight Angus (Dec 17, 2007)

Any ideas?


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## Dwight Angus (Dec 17, 2007)

Finally ordered refurbished Xilica XP4080 PEQ to EQ mains and dual subs. This should help reduce lower sub frequencies below 40 hz that have been clouding mid range levels and provide support in smoothing out upper frequencies.
It should be here in 2 weeks.


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## jtalden (Mar 12, 2009)

Regarding Audyssey first vs. Audyssey last:
There was no previous comment above probably because it seems the opinions are pretty much split on this subject. You can probably get a satisfactory result either way.

My personal suggestion would be to run Audyssey first as:

> You may be using a house curve that differs from the Audyssey default. [Audyssey last would effectively defeat the custom house curve.

> My experience with Audyssey XT (not XT32) is that given a smooth bass response to work with, Audyssey XT can sometimes result in a 9 dB boost of the signal below its calculated cutoff. I don't know if this was fixed in XT32 but I think it might have been. Given a typical rough initial response, Audyssey XT would not result in that low end 9 dB boost as that headroom is absorbed in the EQ of the peaks and dips and thus "used up". [This is only my best guess as to the situation based on my results measuring the SW line output after trying the 2 methods. I only did this 1 or 2 trials some time ago so the results may not hold up for all situations? On request I can post a couple of chart to show where this theory came from if someone wants to see it.]. My only point is that it is possibly that some of the low end boost may actually be worsened by Audyssey so a check the SW line out with Audyssey on vs. Audyssey off may be instructive.

In any case the Xilica will allow a high pass filter or EQ to be set that will help tame the situation if any problem occurs.


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## Dwight Angus (Dec 17, 2007)

jtalden said:


> Regarding Audyssey first vs. Audyssey last:
> There was no previous comment above probably because it seems the opinions are pretty much split on this subject. You can probably get a satisfactory result either way.
> 
> My personal suggestion would be to run Audyssey first as:
> ...


Thanks John
I sent a message to the folks at Audyssey previously outlining my approach to Pre eqing and asked them to advise when to insert MULTEQ. They advised me to insert XT32 after the PRE EQ process. But I will follow your advice and check SW line out (XT32 on vs off) to be sure.


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## Dwight Angus (Dec 17, 2007)

I heard today that my refurbished Xilica XP4080 should arrive this week. I will have a learning curve with this device but I will post updated REW graphs once I load the few filters


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## Sonnie (Apr 11, 2006)

You could use the two outputs on your 5508 and Audyssey will take care of the rest... it will check the distance of each sub, level each sub and then equalize both subs together. No real reason for a Y adapter. Of course with the subs being co-located, the distance and level will be the same anyway... although levels might be slightly difference due to room interaction based on placement of one over the other.

As far as pre-equalizing... can you run a REW sweep and see what you are dealing with first. If you have large peaks, it would be better to get those reduced prior to running Audyssey, as Audyssey does not do very well with large peaks... especially with the level setting. You can check my review of the Denon 4520 (sig link) and see an example of failing to tame a peak prior to running Audyssey. You can work around it, but it is better to get it out of the way for Audyssey.


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## Dwight Angus (Dec 17, 2007)

Hey Sonnie
The y connect reference related to connecting the PEQ to the 5508. I want to pre eq both subs together as one so I was thinking to y connect both subas 1 input. I read your article on the Denon and realized Audyssey cannot tackle the large peaks. So my approach is to pre eq then run Audyssey. That should solve it.


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## Sonnie (Apr 11, 2006)

Oh... okay. I thought you were just using the PEQ on the SVS subs, which if measured together, you could set both PEQ's on each sub the same, which would amount to eq'ing them together. However, if you have a separate PEQ, then yeah, carry on. 

Let us see some before and after graphs if you have time.


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## Dwight Angus (Dec 17, 2007)

Sonnie said:


> Oh... okay. I thought you were just using the PEQ on the SVS subs, which if measured together, you could set both PEQ's on each sub the same, which would amount to eq'ing them together. However, if you have a separate PEQ, then yeah, carry on.
> 
> Let us see some before and after graphs if you have time.


My PB13 Ultras REW sweep looks good except below 40hz is dominate and bloated and muddies mid range frequencies. I have set filters on the subs peq but the correction is limited to a small frequency range & requires a more extensive solution. I should take delivery of the Xilica xp4080 this week and will play with it to get familiar (steep learning curve).

I had submitted REW graphs earlier on the REW forum & I will followup and post some post PEQ graphs for comparison. 

Cheers


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## Sonnie (Apr 11, 2006)

That thing looks kind of expensive. Did you consider the DSpeaker? Or perhaps one of the miniDSP products for considerably less? I am curious why you decided on the Xilica.


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## Dwight Angus (Dec 17, 2007)

Sonnie said:


> That thing looks kind of expensive. Did you consider the DSpeaker? Or perhaps one of the miniDSP products for considerably less? I am curious why you decided on the Xilica.


I bought it 2nd hand. It's been on the road for 2 years but in good shape. Also the Xilica factory is a short drive if I need any repairs.


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## Sonnie (Apr 11, 2006)

Ahhh... makes sense. It certainly looks like an excellent product.


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## Dwight Angus (Dec 17, 2007)

For its age and usage history its in good condition. Looking forward to seeing what it can do and running some more rew graphs to see improvements.


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## Dwight Angus (Dec 17, 2007)

Trying to set filters in standalone PEQ. Dealing with learning curve so bare with me. Looking at sub response in REW EQ screen and some of the suggested filters are 125hz 151 hz. My LPF is 120hz. I thought anything above 120hz will be killed. Should I just ignore this? Don't want to load meaningless filters.


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## JohnM (Apr 11, 2006)

You can tell REW what range you want it to generate filters for, but note that the LP filter is not a brick wall, it rolls off from 120Hz.


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## Dwight Angus (Dec 17, 2007)

JohnM said:


> You can tell REW what range you want it to generate filters for, but note that the LP filter is not a brick wall, it rolls off from 120Hz.


Thanks John
Yeah gathered that after I sent out the question above. I will reset the range to about 125hz down from 200hz to cover LPF and roll off. This will eliminate some of the above lpf filter suggestions.

Cheers


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## Dwight Angus (Dec 17, 2007)

I loaded 3 pre eq filters into standalone PEQ for dual svs PB13 ULtras. I then ran XT32 setup.
I then used REW to confirm changes in signal response. Sub volume was allot lower and lots of audible distortion through the subs. I also noticed sub trim levels increased from 1.0 to 7.0.
Should I have run Audyssey xt32 setup prior to loading peq supplemental filters or is there another step that I missed?


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## Phillips (Aug 12, 2011)

Dwight Angus said:


> I loaded 3 pre eq filters into standalone PEQ for dual svs PB13 ULtras. I then ran XT32 setup.
> I then used REW to confirm changes in signal response. Sub volume was allot lower and lots of audible distortion through the subs. I also noticed sub trim levels increased from 1.0 to 7.0.
> Should I have run Audyssey xt32 setup prior to loading peq supplemental filters or is there another step that I missed?


Hi 

Any mdat files available?

When you unplug the PEQ and go back to normal there is no sign of distortion?
What about when the filters haven't been applied, any distortion through the PEQ?

I am not not familiar with your PEQ but does it have something like Head Room or signal adjustment, trying to think of other name?

What are the filters, gain Q you used?


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## wei (Apr 2, 2013)

:yikes:


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## Dwight Angus (Dec 17, 2007)

Phillips said:


> Hi
> 
> Any mdat files available?
> 
> ...


Ok 
Problem solved. I made adjustments to peq output limiters that solved the distortion issue. I also found I had to run Audyssey xt32 first and then make peq filter adjustments based on REW with audyssey included. No time left tonight to work on it. Will resume tomorrow night. I will post rew graphs once peq filter adjustments are done.


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