# is this how i raise the bottom end of my sealed subs?



## corradizo (Jan 19, 2014)

Hi,

Ive been learning so much here. Thanks for all of the knowledge and help! Im hoping for some guidance with respect to boosting the bottom end <20hz of my sealed subs (they are Epic Empire 8ohm drivers in 1.64cuft = vb and stuffed with R13 about half way) powered by an inuke 3kdsp bridged to 4ohm.

Here is the story:
My sealed subs start rolling off at 60hz in winisd and are down 18.5db at 20hz in the model. 








After measuring with my shiny new UMM6 mic I see that room gain makes them flat to 18hz without any eq! (pics below)

So i did Wayne's house curve test and determined that 28hz sounds about the same as 80hz when 28hz has a 9db boost. So that translates in REW to a 5db/octave setting (i think, i measured it by hand and saw 28hz was 9db higher than 80hz on the graph). I lowered the target level down to better match the curve knowing that i will be setting the gains later using pink noise at 75db (is this ok to do? manually lower the target db?) Then I did the match target piece and got the filters.

































As you can see the subs want to stay flat all the way to 100hz or so and things start to taper off after 18hz quite a bit on the way down to 10hz. Thinking i need to address the later, I manually entered a LS12 @ 20hz and boosted it 12db while simultaneously adding in a PEQ filter at 20hz cutting -11db w/ Q =5 to bring it back down. Is this the right thing to do or should i skip doing this?

Also, did i do the house curve right? Any help and comments would be greatly appreciated.

Lastly, and maybe i should post this in another area, but i have no limiter set on my inuke, do i need to set one, is so what should it be? The drivers are rated at 400w and the inuke being bridged at 4ohm can provide 2075w total or 1037.5w per driver. i keep hearing about fried speakers and am a bit worried. 

best regards,

Pete


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## Peter Loeser (Aug 11, 2012)

I would suggest reading this post: On Minimal EQ, Target Levels, and a Hard-Knee House Curve


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## corradizo (Jan 19, 2014)

Peter Loeser said:


> I would suggest reading this post: On Minimal EQ, Target Levels, and a Hard-Knee House Curve


Thank you, I have read up on this prior to posting (like Johnny #5 in a bookstore :bigsmile and updated my post today with a bunch more info and screenshots. Thank you for jumping in to help!

best, 

Pete


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

Hi Pete,

In recommending that article I think Peter was probably trying to tell you that your EQ technique is rather poor. You’ve probably used more filters than necessary, used notch filters that are a big no-no (#2, 3, 5, 6 and 7 @ 10 and 8.9 Q), and filters so high up that they’re probably going to be blown out when you fire up the main channel speakers (#10 @ 100 Hz). 

Are you really going to cross over to the main speakers at 120 Hz? Whatever high pass you use for the mains, it looks like you could benefit from a “staggered” crossover arrangement for this particular sub – i.e. the low pass being a different frequency from the mains high pass. Setting your subwoofer low pass down to something like 45-50 Hz could serve to lower all that energy you have at the top of the sub (in the 60-100 Hz range). That would make more sense than using a slew of EQ filters to do it (e.g. your filters #5, 6, 7). After that, using a couple of cut filters at 28 and 45 Hz and maybe a boost filter at ~53 Hz (if it results in a measured improvement – if not then you have a null so don’t EQ it) would probably be all the EQ you need, or pretty close.




corradizo said:


> As you can see the subs want to stay flat all the way to 100hz or so and things start to taper off after 18hz quite a bit on the way down to 10hz. Thinking i need to address the later, I manually entered a LS12 @ 20hz and boosted it 12db while simultaneously adding in a PEQ filter at 20hz cutting -11db w/ Q =5 to bring it back down. Is this the right thing to do or should i skip doing this?


It’s fine as long as your subs can handle it. If they start bottoming out, then you’ll want to remove these two filters.




> Also, did i do the house curve right?


Looks like it came out right. The Target curve on your graph shows about a 9 dB boost between 80 and 28 Hz, which is what you came up with in the “sounds the same” test.




> Lastly… i have no limiter set on my inuke, do i need to set one, is so what should it be? The drivers are rated at 400w and the inuke being bridged at 4ohm can provide 2075w total or 1037.5w per driver. i keep hearing about fried speakers and am a bit worried.


If the amp doesn’t have a built-in limiting feature it will have to come from an outboard device. Doesn’t the DCX have a limiting function?

Regards,
Wayne


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## corradizo (Jan 19, 2014)

> In recommending that article I think Peter was probably trying to tell you that your EQ technique is rather poor. You’ve probably used more filters than necessary, used notch filters that are a big no-no (#2, 3, 5, 6 and 7 @ 10 and 8.9 Q), and filters so high up that they’re probably going to be blown out when you fire up the main channel speakers (#10 @ 100 Hz).


Ah, i missed the notch filter part. I didn't realize Q of 10 was bad. 



> Are you really going to cross over to the main speakers at 120 Hz?


I have in-wall mains from monoprice so i think i wanted to compensate with the subs. I'm looking at getting new mains, have been considering building my own in-wall units due to WAF although i'm slowing turning her to my way of thinking...



> Whatever high pass you use for the mains, it looks like you could benefit from a “staggered” crossover arrangement for this particular sub – i.e. the low pass being a different frequency from the mains high pass.


What a great idea! My inuke dsp amp does have a build in LPF so i could use that at 60hz and perhaps leave the mains at 80hz or higher? Hoping you can recommend a starting point here.



> Setting your subwoofer low pass down to something like 45-50 Hz could serve to lower all that energy you have at the top of the sub (in the 60-100 Hz range). That would make more sense than using a slew of EQ filters to do it (e.g. your filters #5, 6, 7). After that, using a couple of cut filters at 28 and 45 Hz and maybe a boost filter at ~53 Hz (if it results in a measured improvement – if not then you have a null so don’t EQ it) would probably be all the EQ you need, or pretty close.


If i put filters in for 28, 45 and 53 what is the most Q I could apply without running into trouble?



> It’s fine as long as your subs can handle it. If they start bottoming out, then you’ll want to remove these two filters.


Thank you, i'm going to try it out and keep a close eye.



> Looks like it came out right. The Target curve on your graph shows about a 9 dB boost between 80 and 28 Hz, which is what you came up with in the “sounds the same” test.


Great, thank you.




> If the amp doesn’t have a built-in limiting feature it will have to come from an outboard device. Doesn’t the DCX have a limiting function?


It does have it as a feature, i'm not sure if i need it or not since the subs are sealed and as such the acoustic suspension protects them from bottoming out. I've read that the subs will "take what they need" which i don't know if it's true. If it's not, are they getting 1000+watts the whole time and i'm trashing them by overheating them?

Thank you for taking the time to help me figure this out!

Pete


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

Hey Pete,



corradizo said:


> I have in-wall mains from monoprice. so i think i wanted to compensate with the subs.
> 
> What a great idea! My inuke dsp amp does have a build in LPF so i could use that at 60hz and perhaps leave the mains at 80hz or higher? Hoping you can recommend a starting point here.


Ah. With those speakers you might actually need that 120 Hz crossover. Sorry, can’t help you on where to start with the staggered crossover frequency. Impossible to do that long-distance. You’ll have to experiment with different frequency settings and slopes (12 dB/octave, 18 dB/octave, etc.) to get that upper frequency hump in the subs to drop where you want it. You might use REW’s RTA feature that would allow you to tweak and see the results in real time (hence the term *R*eal *T*ime *A*nalyzer), rather than using sweeps.




> If i put filters in for 28, 45 and 53 what is the most Q I could apply without running into trouble?


There should seldom be a need for a filter tighter than ~ 8.7 Q (1/6-octave).




> It does have it as a feature, i'm not sure if i need it or not since the subs are sealed and as such the acoustic suspension protects them from bottoming out. I've read that the subs will "take what they need" which i don't know if it's true. If it's not, are they getting 1000+watts the whole time and i'm trashing them by overheating them?


Sealed subs can certainly be bottomed out, if given a powerful enough signal, especially if it’s at the lower frequencies. Overheating is not a problem with program material, as the cone motion itself provides cooling for the voice coil.

Regards, 
Wayne


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## corradizo (Jan 19, 2014)

I just realized that I plugged the laptop directly into the inuke so my measurements were without a lpf!! This explains it. I will try the RTA. I need to get the family out of the house to do that. 

My plan for now:

I will take new measurements with the lpf ON and the mains off (5-200hz sweep). 

I will do another measuremt of just the mains to see how flat they are.

I'll then select a crossover point based on the deficiency of the mains.

Knowing my crossover point I will then build do the house curve (25 or 28hz to the crossover point?)

I will apply the house curve and filters and the set the mains and sub at 75db at mlp setting the receiver to 0db and using the receiver gains (+4db usually on my mains) and setting the receiver gain to zero and using the inuke gain to get to 75db.

Then I will do a full range measuremt of mains and sub and see how I did.

This seems correct? Audio nirvana is near, I can taste it! (Then I need new speakers).

Pete


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

Sounds like a good plan, Pete - good luck with your project!

Regards,
Wayne


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## corradizo (Jan 19, 2014)

I finally found some time to work on this. I really want to give a BIG thanks to you Wayne. The idea of dual crossovers really did the trick! It took a great deal of playing around but i think i've got it nailed. I set my AVR crossover for the mains and center to 80hz first. I then took some measurements and played around with the the iNuke. I bypassed all the filters and only worked with the LPF until i could get the curve to bend right so that i'd need minimal filters after the fact. 57.1hz with an 18db Butterworth did the trick. I then used the REW filter suggestions for the DCX EQ since the iNuke isn't an option (it's said the DCX is quite close to the iNUKE). It came up with some notch filters so i followed your advice and backed them off and then added in a boost at 54hz. The end result i think looks really nice even without smoothing. I also seemed to reduce some ringing which is a cool bonus. I don't know how to evaluate the other things in REW so if you see anything strange, i'm hoping you could point it out to me. Ok, here are the pics. Thanks again!!

Green is the after (i know it's obvious  )
No Smoothing








1/12 Smoothing








1/3 Smoothing








Closely matching to 12db 80-25hz house curve - smoothed at 1/12








Closely matching to 12db 80-25hz house curve - no smoothing!








Waterfall Before








Waterfall After - Less ringing - how can i lower the ringing at 18hz? does this matter since you can't really hear it???








iNUKE








iNUKE








This is my REW file is anyone cares to check it out.
View attachment nailed it.mdat


best,

Pete


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

Glad to hear it’s all working for you, Pete!


corradizo said:


> Waterfall After - Less ringing -


Not necessarily. The green one “looks” better simply because the overall level has been reduced.  More reading on that topic here.




> how can i lower the ringing at 18hz?


 It would require an 18 Hz parametric filter. Not an option on most digital equalizers, also some vintage analog models will EQ down that low.

Regards, 
Wayne


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## corradizo (Jan 19, 2014)

Thanks Wayne. I read through it all and it looks like I fell into the same trap being that the decay looks better at different levels! I'm not prepared to treat the room due to WAF. I'm still not clear on the sub 20hz ringing. Since its inaudible, does it matter? 

I'm now looking at new mains and center. The trend seems to be going towards PA speakers like the Behringer 212xl's. Still researching and seeing what I can get the wife to agree to.


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

corradizo said:


> I'm still not clear on the sub 20hz ringing. Since its inaudible, does it matter?


I typically don't worry about things I can't hear. 



corradizo said:


> I'm now looking at new mains and center. The trend seems to be going towards PA speakers like the Behringer 212xl's. Still researching and seeing what I can get the wife to agree to.


Don't know who exactly is doing that, but IMO using cheap PA speakers for HT is not a good trend...


Regards,
Wayne


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## corradizo (Jan 19, 2014)

OK. I guess I'm out of things to obsess about for now. The pa stuff comes from here:

http://www.avsforum.com/forum/89-speakers/1519940-behringer-eurolive-b215xl-15-2-way-l-r-mains.html

I was looking at building these:

http://www.diysoundgroup.com/waveguide-speaker-kits/fusion6-kit.html

I should probably start another thread to discuss my "new" obsession with mains.

Pete


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## corradizo (Jan 19, 2014)

Today was a breakthrough day! I figured out how to use the ASIO software today and so I set out to do some more measurements, this time of my Sub and the LCR's. I am going to attach the mdat file to this post in hopes you might have a few minutes to look it over and help me understand what i've captured? I did a sub sweep without filters/lpf, sub sweep with filters/lpf as per my previous posts (except this time i pointed the mic at 45 deg towards the front of the room, all measurements today were done like this) and then i did sweeps of the LCR speakers with the sub physically turned off and off. I don' know where to start. Are my "mains" doing ok? Have i blended my sub with them well? I can't seem to determine this. Any help would be greatly appreciated.

Here is the file:
View attachment sweeps of all speakers.mdat


thanks,

Pete


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

Sub response looks pretty good, but you might want to dial in a house curve.









*Subwoofer*​

Left and right both show a big hole between 600-200 Hz, the result of the limited extension of your in-wall speakers. IOW, they don’t get low enough to blend with the sub. In addition, the right speaker has a nasty spike just north of 400 Hz that is probably audible.









*Left*








*Right*​

Regards, 
Wayne


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## corradizo (Jan 19, 2014)

Thanks Wayne! I saw the dip and did more measurements today. I crossed the subs at 200hz to try and make up for the issues below there. It sounds... Different. The graphs showed some big dips under 200hz that the subs corrected but the 200 to 600 hz range is just not good I agree. You'd think 8" woofers could manage this. They do have a 0, -3, -6 settings on them. They are at zero. Would going to -3 or -6 cut the highs so I can flatten the response? Not sure what these settings do.

Best,

Pete


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

corradizo said:


> You'd think 8" woofers could manage this. They do have a 0, -3, -6 settings on them. They are at zero. Would going to -3 or -6 cut the highs so I can flatten the response? Not sure what these settings do.


I assume you’re talking about the in-wall speakers? ‘Cause I can’t imagine that 8-inch subs would dig down to 18 Hz. If so, the settings are probably for tweeter attenuation. No need to engage them unless you think the highs are too bright.

Regards,
Wayne


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## corradizo (Jan 19, 2014)

Yep. The in walls. I guess I misunderstood what they did. Thank you.


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## corradizo (Jan 19, 2014)

So I found a great deal on a pair of Behringer 212xl PA speakers, i got them brand new. I disconnected my in wall LCR and set them on top of my subs (luckily this puts the compression drivers at about 36" high which is ear height on my couch). I ran Audyssey 2eq which set my new mains at 70hz and used my UMM6 mic with REW to set everything to 75db. I must say i'm really impressed. As discussed I haven't heard many different speakers so it wouldn't be right for me to compare them to anything but my inwalls but the detail there and the soundstage were awesome. Playing some music i could pick out where the instruments were and so forth. I've included a link to my mdat after doing some measurements. If you have a chance, i'd love to hear your opinion.

https://www.dropbox.com/s/0krgbuk4z7er9bf/new speakers after audyssey 2eq.mdat

thanks,

Pete


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