# EQ'd w/1124p w/graphs



## sickboy013 (Feb 28, 2009)

Hey guys, I picked up an 1124p last week. I have the downfiring version of the Elemental Designs a5-350 sub. I finally got around to downloading v5 of REW and dialing the eq in today. I must say I really like the new version! :T With the -10dBv setting on the 1124p I had to dial my sub level way back in my receiver to around -14 to stay out of the red, so I switched it to the +4dBu. It now maxes out at the top of the green LEDs to keep me away from digital distortion. From what I have read there should be no issue to doing that, am I right?

Here is what the sweep looked like with no eq. I have tons of natural room gain between 27 and 48 hz. I have also changed the graph limits, since I cross over my system at 100hz I don't really care what is going on above 100hz. So I know it's out of the normal specs for displaying graphs. 










Using 4 filters via the 1124p and REW I ended up with this. I did not boost any levels, just cut. Can anyone explain what the phase graph means?










Here it is without the phase graph.










All in all I am very happy with how this has turned out! And better yet I haven't had the hum issue with my 1124p!


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## sickboy013 (Feb 28, 2009)

I forgot to add something I found quite funny. My wife saw the eq and she says that it looks quite fancy, so she calls it 'The Business Maker'!

So from now on it's new name is The Business Maker! :rofl2:


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## JohnM (Apr 11, 2006)

That's a very nice looking response, good job with the EQ. The phase stays mostly around -180/180 degrees (those are actually the same point, phase wraps around from -180 to 180) which means through that region the sub is inverting. You need to look at measurements of the sub plus each main speaker in turn to establish whether that is the best phase for the sub by looking at the response through the crossover region.


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## sickboy013 (Feb 28, 2009)

JohnM said:


> That's a very nice looking response, good job with the EQ. The phase stays mostly around -180/180 degrees (those are actually the same point, phase wraps around from -180 to 180) which means through that region the sub is inverting. You need to look at measurements of the sub plus each main speaker in turn to establish whether that is the best phase for the sub by looking at the response through the crossover region.


Thanks John. Ok from what I understand, my sub is flipping from -180 to 180 (where it goes from bottom to top and vice versa) which is reletively the same phase. As far as the phase alone is sitting is that alright? Should the phase not be inverting like it is? And as far as measuring the sub + each main, I should check that through the crossover point to make sure it's not creating a null, right?


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## JohnM (Apr 11, 2006)

sickboy013 said:


> as far as measuring the sub + each main, I should check that through the crossover point to make sure it's not creating a null, right?


Right. Whether the sub is better inverting or not depends on what the mains are doing and where you sit relative to the sub and mains, easiest is definitely to measure and see what works best. You can also vary the sub distance setting to tweak the result.


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## sickboy013 (Feb 28, 2009)

JohnM said:


> Right. Whether the sub is better inverting or not depends on what the mains are doing and where you sit relative to the sub and mains, easiest is definitely to measure and see what works best. You can also vary the sub distance setting to tweak the result.


Ok. Will playing around with the phase have any adverse effects on the response? I don't think it would with varying the distance, but I'm unsure with the phase. Would I have to re-eq if the phase is altered?


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## JohnM (Apr 11, 2006)

Altering the phase will have no effect on the sub alone, but will affect how it interacts with the mains. Even before you do anything with phase you need to see how the sub behaves with the mains, as there can be a fair degree of overlap which can change things quite a bit - peaks that were there with the sub alone can disappear when the mains come in, or new ones can appear. All gets very tricky


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## sickboy013 (Feb 28, 2009)

JohnM said:


> Altering the phase will have no effect on the sub alone, but will affect how it interacts with the mains. Even before you do anything with phase you need to see how the sub behaves with the mains, as there can be a fair degree of overlap which can change things quite a bit - peaks that were there with the sub alone can disappear when the mains come in, or new ones can appear. All gets very tricky


Thanks again for your help John. I'll mess around with this next weekend and see what I can do.  I'll update this thread when I have the results.


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

> I switched it to the +4dBu. It now maxes out at the top of the green LEDs to keep me away from digital distortion. From what I have read there should be no issue to doing that, am I right?


Correct.




> Using 4 filters via the 1124p and REW I ended up with this. I did not boost any levels, just cut.


You can see more on the topic here, but basically boosting vs. cutting is largely academic (unless we’re talking about nulls). When you look at the equalizer’s electrical response (you can do that with REW by checking the “Filters” box), using a boosted filter you can see a big hump in the signal, right? Well, use only cuts instead, and what do you have _between_ the cuts? Big humps in the signal.

Looking at your two graphs it appears that you applied some really severe EQ filters, some probably on the order of -15 dB or more, to get response as flat as the second graph shows: Where initially you had response dropping about 15 dB/octave below ~30 Hz, you now have response that doesn’t start a serious drop until ~18 Hz. So even employing only cutting filters, you’ve ended up severely boosting response <30 Hz. Looking at REW’s filter response plot would confirm this.

So – it’s great that you were able to flatten response, just don’t think it was accomplished with no boosting. 

Regards,
Wayne


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## vann_d (Apr 7, 2009)

Wayne A. Pflughaupt said:


> Where initially you had response dropping about 15 dB/octave below ~30 Hz, you now have response that doesn’t start a serious drop until ~18 Hz. So even employing only cutting filters, you’ve ended up severely boosting response <30 Hz. Looking at REW’s filter response plot would confirm this.
> 
> So – it’s great that you were able to flatten response, just don’t think it was accomplished with no boosting.
> [FONT]




This makes absolutely no sense to me.

Is there a greater load on the amplifier at 18 Hz after filters than there was before filters? Will he now clip the signal below 30Hz easier than he did before? I don't see how this would be the case so I don't see how you can call it "boosting". :huh:


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

> Is there a greater load on the amplifier at 18 Hz after filters than there was before filters? Will he now clip the signal below 30Hz easier than he did before?


Well, take a look at his two graphs. Before EQ, 18 Hz was 20 dB lower than the peak in response at ~48 Hz. After EQ, 18 Hz is only ~5 dB lower than the (new) response peak at ~36 Hz. He's going to have to increase his sub's volume level to make up for the ~15 dB in audible gain lost to equalizing. This means that there will now be ~15 dB more power delivered/required at 18 Hz than before (i.e. the difference between 18 Hz's level relative to the pre- and post-EQ peaks). So the answer is “yes and “yes.”

It’s all explained to greater detail, with graphs, in post I linked in my previous post. Did you study it?

Regards,
Wayne


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## sickboy013 (Feb 28, 2009)

Wayne A. Pflughaupt said:


> Correct.
> 
> 
> You can see more on the topic here, but basically boosting vs. cutting is largely academic (unless we’re talking about nulls). When you look at the equalizer’s electrical response (you can do that with REW by checking the “Filters” box), using a boosted filter you can see a big hump in the signal, right? Well, use only cuts instead, and what do you have _between_ the cuts? Big humps in the signal.
> ...


Well, what I meant by no boosting was I didn't apply gain in the filters anywhere in my response.  

The only reason my graphs are so different is because running with no EQ I start clipping in REW because of that peak so I have to lower the level. With the EQ going I can actually run sweeps at the level I should be able to without clipping. I really didn't have to boost levels on my sub or avr too much from before the filters were applied to after. My sub is rated to +/- 3db at 19hz, so I should be able to have usable extension that low.

Actually my filters are as follows...

Filter 1 - Frequency 48.00 = 50 -4 Gain = -14 BW = 6
Filter 2 - Frequency 29.88 = 32 -5 Gain = -9 BW = 9
Filter 3 - Frequency 42.50 = 40 +5 Gain = -8 BW = 10
Filter 4 - Frequency 88.00 = 80 +8 Gain = -5 BW = 6


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## sickboy013 (Feb 28, 2009)

Wayne A. Pflughaupt said:


> Well, take a look at his two graphs. Before EQ, 18 Hz was 20 dB lower than the peak in response at ~48 Hz. After EQ, 18 Hz is only ~5 dB lower than the (new) response peak at ~36 Hz. He's going to have to increase his sub's volume level to make up for the ~15 dB in audible gain lost to equalizing. This means that there will now be ~15 dB more power delivered/required at 18 Hz than before (i.e. the difference between 18 Hz's level relative to the pre- and post-EQ peaks). So the answer is “yes and “yes.”
> 
> It’s all explained to greater detail, with graphs, in post I linked in my previous post. Did you study it?
> 
> ...


Isn't clipping audible? The levels I listen to movies at max is -10 below reference. I have demoed some pretty heavy bass scenes, i.e. Master and Commander, etc. I have had no issues with chuffing from the ports, no mechanical clanking sounds, or anything else abnormal. So my question is am I driving this sub at unreasonable levels with the EQ?


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## sickboy013 (Feb 28, 2009)

Wayne I have another question. Where in REW do I find the filter response plot?


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## vann_d (Apr 7, 2009)

I've read your posts and appreciate the content. I still don't understand this statement...



Wayne A. Pflughaupt said:


> He's going to have to increase his sub's volume level to make up for the ~15 dB in audible gain lost to equalizing.


Why? Does your logic assume that the +15dB peak was at the correct level and everything else too low? This is where I don't understand your argument. Perhaps he was already at the correct 18 Hz level before equalizing. He certainly would not need to adjust his amplifier gain by 15 dB to maintain the same output at 18 Hz that he had before eq. Your graphs do no include the effect of the room modes that the filters were put in place to tame.

I know my room has a huge gain at 36 Hz. I put in a big filter to get rid of that big peak. I did not have to adjust my gain but just a tad to get levels where I needed them after eq. Certainly nothing close to the amount of negative gain in my filter...


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

sickboy013 said:


> Isn't clipping audible? The levels I listen to movies at max is -10 below reference. I have demoed some pretty heavy bass scenes, i.e. Master and Commander, etc. I have had no issues with chuffing from the ports, no mechanical clanking sounds, or anything else abnormal. So my question is am I driving this sub at unreasonable levels with the EQ?


Doesn’t sound like it. Believe me, if you overdrive the sub, you’ll know it! It’ll bottom out and make all kinds of rude noises.

However, a lot of subs these days, especially high-performance models, have built in limiting to prevent overdriving them.



> Wayne I have another question. Where in REW do I find the filter response plot?


I’m not using V5 yet, but in V4 there are several boxes below the measurement – “Target,” “Corrected,” “Mic/Meter Cal,” etc. Look for the one that says “Filters + Target” (which will show the effect of the filter and your electronic crossover together). Un-check the other boxes, especially for the measurement, and you will see the electronic response of the filters used (from the EQ panel).

Regards,
Wayne


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

vann_d said:


> I've read your posts and appreciate the content. I still don't understand this statement...
> 
> 
> 
> ...


 Essentially, yes. Before EQing, a peak in response (caused by the room) is naturally the loudest thing you are hearing. As such, the level the sub was initially set at was based on that peak: If you used an SPL meter to adjust your 5.1 levels, for instance, the dB reading you get for the sub will be the loudest frequency it’s generating.

Naturally, if you cut down the peak via equalization, the sub will now sound noticeably quieter than before. You’ll have to increase the sub’s volume to compensate.




> I know my room has a huge gain at 36 Hz. I put in a big filter to get rid of that big peak. I did not have to adjust my gain but just a tad to get levels where I needed them after eq. Certainly nothing close to the amount of negative gain in my filter...


Even if only a minor adjustment was needed in your case or even none at all, the situation is that your sub now has relatively flat response. This means all frequencies above and below your 36 Hz peak are now acoustically equal to the former peak, when before they were below it. In other words, they technically have been boosted, even if you used no positive-gain filters.

The point is, using boost or cut filters gets the same acoustic results. There is no inherent advantage to using cut-only filters, as is commonly (and wrongly) circulated on the various forums.

Regards,
Wayne


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## vann_d (Apr 7, 2009)

Thanks Wayne I appreciate the explanation


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## sickboy013 (Feb 28, 2009)

Wayne,

I really appreciate your explanations and comments. You have definately helped me understand more about eq'ing and helped me look at it from different angles.


Also, thanks to vann_d as well for asking for clarification!

:T


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## sickboy013 (Feb 28, 2009)

Wayne,

I also found the filter response plot. Here's the graph. What are your thoughts?


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

Looks like you have the “Invert Filters” box enabled as well, since you’re using cut-only filters.

Your equalizing looks fine, though. :T You might have raised the Target and used a combination of boost and cut filters, but the final outcome is essentially the same. If you do end up with the sub unloading at the lowest frequencies, you might try that tact, as it would cause more of a roll-out below 20 Hz (i.e. along of the lines of what your initial graph shows).

I would suggest that your 88 Hz filter is probably right in the range of your receiver’s crossover frequency, and any effect it has is probably being blown out by what the main speakers are generating in that region. You might take mains/sub sweeps with and without that filter to see if it’s actually accomplishing anything.

Anyway, just thought this was worth mentioning because of all the “cut only” baloney that floats around the Web. We had a case here a few years ago of a guy who went so overboard cutting that there wasn’t enough level left coming out of the BFD to drive his sub - no kidding. :scared:

Regards,
Wayne


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## sickboy013 (Feb 28, 2009)

Wayne A. Pflughaupt said:


> Looks like you have the “Invert Filters” box enabled as well, since you’re using cut-only filters.
> 
> Your equalizing looks fine, though. :T You might have raised the Target and used a combination of boost and cut filters, but the final outcome is essentially the same. If you do end up with the sub unloading at the lowest frequencies, you might try that tact, as it would cause more of a roll-out below 20 Hz (i.e. along of the lines of what your initial graph shows).
> 
> ...


I see what you are saying. Instead of having the target at like, 75db, I would set the target higher. That way I end up cutting less, but boosting some frequencies up towards the higher mark so I wouldn't have to bump up the level on my receiver or sub (technically) to compensate for the loss in volume?

Also my levels on the eq'd graph could have been run at lower level in REW, so that would show the sub rolling off a little higher. My question is do I want my sub rolling off faster than what it's rated at (+/- 3db @ 19hz)? I feel if I have it rolling off faster than I am not getting what I want out of this sub.


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

> I see what you are saying. Instead of having the target at like, 75db, I would set the target higher. That way I end up cutting less, but boosting some frequencies up towards the higher mark so I wouldn't have to bump up the level on my receiver or sub (technically) to compensate for the loss in volume?


Basically yes, although minimizing or not having to re-adjust the receiver’s sub level isn’t an objective. Typically I feel it’s better to use less-severe gain settings if possible, which using a combination of boost and cut filters would accomplish in your case. But be that as it may, I probably would have opted for the additional extension afforded by the cut-only filters you employed. Increased extension is a good thing! (As long as the sub can support it, of course.)



> My question is do I want my sub rolling off faster than what it's rated at (+/- 3db @ 19hz)? I feel if I have it rolling off faster than I am not getting what I want out of this sub.


As long as you’re happy with the equalization, there’s no good reason to change it. :T

Regards,
Wayne


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## sickboy013 (Feb 28, 2009)

Wayne A. Pflughaupt said:


> Basically yes, although minimizing or not having to re-adjust the receiver’s sub level isn’t an objective. Typically I feel it’s better to use less-severe gain settings if possible, which using a combination of boost and cut filters would accomplish in your case. But be that as it may, I probably would have opted for the additional extension afforded by the cut-only filters you employed. Increased extension is a good thing! (As long as the sub can support it, of course.)
> 
> As long as you’re happy with the equalization, there’s no good reason to change it. :T
> 
> ...


I'm pretty happy with it. I'll just have to pay close attention to it for the next little bit and if I neeed to make an adjustment I'll give the other method a shot.

Thanks!:T

-Ed


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## sickboy013 (Feb 28, 2009)

Wayne,

I got to messing around with REW earlier. I did not have it hooked up to run sweeps but I messed around with the filters in the EQ section. In the predicted EQ filters section here is what I am currently running. It is pretty much identical to the sweep I ran and posted on the first page, but at a lower sweep level.










This next predicted EQ sweep is what I came up with going by your advise. I raised the target level from 75 to 78.3. After playing around with it quite a bit it seems like 78.3 is a nice little sweet spot. It generates 4 filters, compared to 5-9 with raising the target level a little more or lowering it a little. It also produced the best looking response. I have yet to run a sweep because I don't want to haul my computer out into my family room. It ended up using 3 filters to cut and 1 to boost. It really helped the higher end of the response.










Filters are...

1 - Freq. 48 = 50 -4 Gain = -11 BW = 7
2 - Freq. 63.85 = 63 +1 Gain = 9 BW = 9
3 - Freq. 42.50 = 40 +5 Gain = -6 BW = 12
4 - Freq. 29.55 = 32 -6 Gain -5 BW = 9

How good is REW at actually nailing predictions? It seemed spot on with the current one I am on. I am wondering if I could employ the newer/better predicted filters and be good until I decide to run some sweeps... again.


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## JohnM (Apr 11, 2006)

sickboy013 said:


> How good is REW at actually nailing predictions?


Very good


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

> I am wondering if I could employ the newer/better predicted filters and be good until I decide to run some sweeps... again.


Sure, you can load the new set of filters into a separate memory slot of the BFD. You might have to re-adjust your sub’s level when switching between them, though. Since , as you noted, the second set raises the upper end of the sub’s response,be listening for audible changes in that region.

Regards,
Wayne


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## sickboy013 (Feb 28, 2009)

JohnM said:


> Very good


Ok that is what I was thinking!  Just wanted to make sure. Thanks for the program John it's awesome! The new version is great! :T



Wayne A. Pflughaupt said:


> Sure, you can load the new set of filters into a separate memory slot of the BFD. You might have to re-adjust your sub’s level when switching between them, though. Since , as you noted, the second set raises the upper end of the sub’s response,be listening for audible changes in that region.
> 
> Regards,
> Wayne


That is what I am going to do. I was thinking that I would probably have to re-adjust the levels. I'll give it a shot and when I get a chance, I'll run some more sweeps!


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## sickboy013 (Feb 28, 2009)

Hey guys, would you check out this graph and tell me what you think. I was reading up a little on the hard knee curve and decided to give it a whirl. I haven't ran any sweeps with these filters. I was just playing around in REW.










I applied the following filters.

Freq- 48.00 = 50 -4 Gain = -10 BW = 7
Freq- 63.85 = 63 +1 Gain = 9 BW = 8
Freq- 44.50 = 40 +9 Gain = -5 BW = 8
Freq- 21.50 = 20 +6 Gain = 8 BW = 11

The one I am concerned about it the gain at 21.5hz. I added that manually to bring the bottom end up a little. I am thinking I should be alright, but is there any cause for concern?

Edit: I had the thought that it shouldn't really matter that I have it boosted because in turn it is almost like I am 'cutting' the upper end for the hard knee curve without really 'cutting'. Does that make sense? Am I on the correct line of thinking here?


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

> Hey guys, would you check out this graph and tell me what you think.


Looks good, but the real question is whether or not you like the way it sounds. 




> The one I am concerned about it the gain at 21.5hz. I added that manually to bring the bottom end up a little. I am thinking I should be alright, but is there any cause for concern?


Impossible for us to say, as it depends on your sub’s capabilities and how hard you drive it. Typically though, if you stress a sub it’ll start making rude noises when the driver bottoms out. Many commercial subs include built-in limiting to prevent overloading. A good way to know that, if there is no mention of built-in protection in the manual, is that at a certain point you keep turning up the system but the level of bass does not increase with it. 




> Edit: I had the thought that it shouldn't really matter that I have it boosted because in turn it is almost like I am 'cutting' the upper end for the hard knee curve without really 'cutting'. Does that make sense? Am I on the correct line of thinking here?


Not sure I follow, but if you recall earlier in this thread it was discussed that boosting or cutting is largely academic and gets the same result in the end, once the sub’s volume is re-calibrated to compensate for the increase or loss in gain from equalization.

Regards,
Wayne


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## sickboy013 (Feb 28, 2009)

Wayne A. Pflughaupt said:


> Looks good, but the real question is whether or not you like the way it sounds.


Thanks. Does the low end look okay or should it be tweaked a little different? I wanted to boost it up to be along the lines of the 'shelf' part of the curve, without try to boost it out of it's tuning +/- 3db at 19hz. The only thing that sounds a little weird is watching regular TV, but I think I need to give it a little more time. Am I along the right lines here?



Wayne A. Pflughaupt said:


> Impossible for us to say, as it depends on your sub’s capabilities and how hard you drive it. Typically though, if you stress a sub it’ll start making rude noises when the driver bottoms out. Many commercial subs include built-in limiting to prevent overloading. A good way to know that, if there is no mention of built-in protection in the manual, is that at a certain point you keep turning up the system but the level of bass does not increase with it.


I listened to some DVD reference material again with these filters. I noticed a lot more deep bass. Everything seemed to shake a little more. The bass also seemed to blend a little better.



Wayne A. Pflughaupt said:


> Not sure I follow, but if you recall earlier in this thread it was discussed that boosting or cutting is largely academic and gets the same result in the end, once the sub’s volume is re-calibrated to compensate for the increase or loss in gain from equalization.


Sorry Wayne, I was just thinking/typing out loud. I just wanted to make sure (because I am still learning) that I am using the correct methods.


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