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Discussion Starter #1 (Edited)
Well I am back again, I have some time to devote to making some measurements now that I have all of my acoustical treatments done. But I am not sure something is right. I am now using a Behringer Mic and pre-amp/mixer and I re-calibrated my sound card, etc. Here is my first measurements for each sub by themselves. I seem to be getting some sort of reverberation or at least that what the graphs look like, any ideas?

Left Sub
View attachment 12686
Right Sub
View attachment 12687
Both Subs
View attachment 12688
 

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Re: Slaughter House Cinema Revisisted

That kind of response occurs if monitoring is active or there is feedback caused by, for example, having Line In selected as one of the playback sources.
 

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Discussion Starter #6
Re: Slaughter House Cinema Revisisted

I will have a look at that and re-set up everything I have to do that anyhow to get my input levels set on my BFD.
 

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Discussion Starter #7
Re: Slaughter House Cinema Revisisted

Anything wrong with using a digital (TosLink) out on my computer to the AVR and using the analog input for the mic readings.
 

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Re: Slaughter House Cinema Revisisted

Anything wrong with using a digital (TosLink) out on my computer to the AVR and using the analog input for the mic readings.
How would you create the soundcard calibration file?

brucek
 

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Discussion Starter #9 (Edited)
Re: Slaughter House Cinema Revisisted

Ok I think I figured out the problems, something was not set right on my AVR and I was outputing too love a a level and it may have been clipping the subs as they were set really high. I have the subs level down REAL low and the sub out on the AVR high, and the input level calibrated on the BFD so i think I am good to go. Here are the new graphs:

Left Sub
View attachment 12739

Right Sub
View attachment 12740

Both
View attachment 12741
 

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Discussion Starter #10 (Edited)
Re: Slaughter House Cinema Revisisted

I adjusted the sub levels so they were more evenly matched at 75db+- .5db then took 3 more measurements, right, left, both then applied the corrections, and then a measurements on boths subs after applying the filters, what do you think?

Right Sub Before Correction/Filters
View attachment 12742

Left Sub Before Correction/Filters
View attachment 12743

Both Subs Before Correction/Filters
View attachment 12744

Corrections applied to both sub measurement
View attachment 12745

Measurement of both subs after filters were applied to the BFD
View attachment 12746
 

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Discussion Starter #11 (Edited)
Re: Slaughter House Cinema Revisisted

I discovered something interesting, although not surprising, my Yamaha RX-V663 AVR will treat the front, center and surround speakers as sub woofers if the speaker size is set to LARGE.

If you auto calibrate the system it will attempt to determine not only the levels and distance but also the size of the speaker (mid bass/woofers) based on the frequency response. So in short if it thinks the speaker is capable of outputting sub bass frequency it will include them when outputting frequencies below the crossover point.

So what I discovered was that when I set all the speakers to SMALL (Front, Center, Surround, Surround Back 7.1) and set the Sub woofer frequency to Sub Woofer only the crossover fed the low frequencies to the subs and the high freq to the rest of the speakers, like it should.

The way it was, all freq were being fed to the front,center,surround, surround rear, and the low freq were being sent to the subs. This with the AVR configuration for the Front, Center, Surround, Surround Back, speakers size set to Large, based on what the initial calibrations figured the speaker size was.

My Crossover is set to 80hz. I understand that there will be a certain amount of level being output to the rest of the speakers at the crossover point, but the way it was the main speakers were being fed the full freq range. I am sure that would effect the image/stage presence quality of the audio. I would have never known unless I had calibrated my BFD levels with the mains off, then with the subs off and the mains on to set the levels after setting the input level of the BFD.

The Yamaha RX-V663 manual is VERY confusing. One graph it says no LFE is sent the the mains if the setting is set to SUBWF. Here is the manual section.
View attachment 12752
 

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Re: Slaughter House Cinema Revisisted

I adjusted the sub levels so they were more evenly matched at 75db+- .5db then took 3 more measurements, right, left, both then applied the corrections, and then a measurements on boths subs after applying the filters, what do you think?



Looks to me like the filters weren’t matched to the peaks very well...

Regards,
Wayne
 

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Discussion Starter #13
Re: Slaughter House Cinema Revisisted

Well I am manually setting the filters and based on the settings it only asked for me to set three of them and I double checked them. I am setting the filters in linked mode, I am wondering if I should set filters for each sub as I am sending a left and a right channel to the BFD and to the subs but I have the BFD in linked mode.
 

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Discussion Starter #14
Re: Slaughter House Cinema Revisisted

Maybe I missed a step in the process? How do I setup a house knee curve, or should I even attempt that at this point :hide:
 

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Re: Slaughter House Cinema Revisisted


Well I am manually setting the filters and based on the settings it only asked for me to set three of them and I double checked them.
What do you mean, “the settings it only asked for?” I’ve never had REW ask for anything when I was setting filters manually. :huh:

When you manually tweak the filters, the dotted line shows what your predicted response will be once they are applied. Notice the dotted line in your 4th graph pretty much matches the second sweep you took in the 5th graph. So, with your baseline graph, adjust the bandwidth, gain and frequency center to flatten out the two peaks with minimal affect on the dip between them.

Maybe I missed a step in the process? How do I setup a house knee curve, or should I even attempt that at this point
The house curve file should be loaded in before you start equalizing.

Regards,
Wayne
 

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Re: Slaughter House Cinema Revisisted

I think I would check to see if the subwoofer has a crossover on while the receiver does also, or if maybe it needs to be set higher on the sub. The crossover area looks like it rolls off kind of quickly. Also, when you compare your results after eq you might let REW detect the target level or set it back to where you started. Depending on previous settings where the graph settings were prior, we sometimes need to go back and change the target to where we want it to be set at over again. For example if you were measuring your mains for a 75 target in one graph but an 80 target for the subwoofer, when you remeasure in your subwoofer after equalization in the second window again if you deleted your mains measurement, it's going to display a 75 target again.
 

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Discussion Starter #17
Re: Slaughter House Cinema Revisisted

I think I would check to see if the subwoofer has a crossover on while the receiver does also, or if maybe it needs to be set higher on the sub. The crossover area looks like it rolls off kind of quickly.
I saw that too however the subs are both set to max (160hz) and on the AVR it is set for 80hz, I am not sure there is anything I can do. See post about the speaker setup on my receiver, that may have something to do with that.

Also, when you compare your results after eq you might let REW detect the target level or set it back to where you started. Depending on previous settings where the graph settings were prior, we sometimes need to go back and change the target to where we want it to be set at over again. For example if you were measuring your mains for a 75 target in one graph but an 80 target for the subwoofer, when you remeasure in your subwoofer after equalization in the second window again if you deleted your mains measurement, it's going to display a 75 target again.
Ah, right the subs together are only going to increase the output. Should I measure and set the EQ filters for both together or am I missing what you are saying?
 

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Discussion Starter #19 (Edited)
Re: Slaughter House Cinema Revisisted

I am wondering if the idea of elevating my subs was a good idea. bpape recommenced that I raise then off the floor a little to see what kind of effect it would have, and I just left them there ;-) My floor is concrete and it seems that I got a better responce out of my old 8" polk than I do out of the pair of eD A2-300's LOL

Currently I have them with the ports facing each other firing down. The screen wall is now dead(er) with 2" of 703 and the corners are filled with supper clunk 703 so I think I have a good amount sound treatment, along with the 8-2x4'x2" 703 panels I have on the side walls.

View attachment 12790
 

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Discussion Starter #20 (Edited)
Re: Slaughter House Cinema Revisisted

Ok after following the instructions on Wayne's post on setting the filters on the BFD I discoverd I was doing it all wrong. Here are some new readings:

Predicted corrections
View attachment 12910

First reading after filters applied
View attachment 12911

Tweaked a bit.
View attachment 12912

I think I am getting the hang of it, but boy, you mess with one spot ot screws with the others LOL

Thoughts?
 
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