# My measurements - looking for comments



## stangbat (Apr 8, 2008)

*Edit: See Post 6 for correct frequency response measurements. Setup information in this post is correct, the plots are junk.*
Long time lurker (almost a year), first post. I am slowly working towards an HT system. Right now I have added a sub to my 2 channel setup. I've been setting things up with REW and I'm looking for some comments about my measurements. Mainly I'm wondering if it looks like I'm getting valid measurements and doing this right.

Some information on my setup:
-2.1 channel, receiver is an Outlaw RR2150 which has built in bass management
-I can select sub crossover frequencies of 60, 80, 100 Hz. The crossover is 2nd order Butterworth. I have selected 60 Hz.
-My main LR are vented 3.5 way towers and have an f3 of around 41 Hz.
-My sub is a 15" Dayton RSS390HF, sealed in a 22" cube powered by an Oaudio 500 watt plate amp

General comments:
-I have calibrated my sound card, it looks good.
-I am using a "new model" RS analog meter. I am using the cal files from this site.
-I have set soundcard levels and calibrated the mic SPL
-No smoothing applied to the graphs

On to the measurements:

*Mains full range*









My comments:
-Huge room mode peaking at 47 Hz.
-I'm guessing the nulls are the room talking?

*Mains with 60 Hz crossover applied. No sub*









My comments:
-Seems like you'd expect more of a drop below 60 Hz? Or is my noise floor too high?

*Sub by itself with 60 Hz crossover applied*
Note: I have EQ a cut at 47 Hz to try and cancel the room mode from the mains. This is the reason for the dip at that frequency









My comments:
-I see more trash between 100-200 Hz than I'd expect with the 60 Hz crossover

*Sub with mains, phase at 0 degrees*









My comments:
-Looks terrible

*Sub with mains, phase at 180 degrees*









My comments:
-Looks much better

*Sub with mains, phase at 90 degrees*









My comments:
-This is the best I've been able to get so far

What is funny is that with the sub, the first impression was that I have less bass. I had become accustomed to the huge room mode with the LR alone. Now that I can take it out, I have to get used to the "new" sound.

Thanks for looking. I appreciate any comments/suggestions/tips.

Edit: Sorry I left the mic calibration on the graphs. Oops.


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## brucek (Apr 11, 2006)

> Mains with 60 Hz crossover applied. No sub
> My comments:
> -Seems like you'd expect more of a drop below 60 Hz? Or is my noise floor too high?


You simply do not have that set of mains crossed. That is full range, or your sub is on.

brucek


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## stangbat (Apr 8, 2008)

brucek said:


> You simply do not have that set of mains crossed. That is full range, or your sub is on.
> 
> brucek


I just ran it again. Sorry, the graph is right. Sub is off, 60 Hz crossover set on the receiver. You can see there is a several dB drop between with and without the sub. But I agree it doesn't seem like as much as you should see. So I'm also wondering what is up. Maybe my noise floor is not low enough? Or I have something set wrong in REW?


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## brucek (Apr 11, 2006)

> Sorry, the graph is right.


Below is a 60Hz - 2nd order bass limited crossover target.









Below is your 60Hz - 2nd order bass limited crossover mains.










Something is not working or set in your receiver. It isn't REW or noise. :huh:

brucek


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## stangbat (Apr 8, 2008)

brucek said:


> Below is a 60Hz - 2nd order bass limited crossover target.
> 
> Below is your 60Hz - 2nd order bass limited crossover mains.
> 
> ...


*Edit: Ignore below. I'm going back through REW calibration and I think I have it figured out. I'll post new graphs later.*

Okay, here is why it looks like that. The following is my room with nothing on. You can see the slope of the graph with no noise follows what we are seeing with the response. It follows the inverse of the mic calibration? Why would it be doing that?

*Mic attached, quiet, calibration file loaded*








*Mic attached, quiet, no calibration file loaded*







-Still have a rising response on the bottom

*Microphone removed, no calibration file loaded*







-Same thing

*Sound card looped back, no mic cal, C weighting unchecked*







-Looks good :scratchhead:


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## stangbat (Apr 8, 2008)

Okay, I think I got things figured out. I had to uncheck "Stereo Mix" in the input controls of my sound card mixer. So below are graphs of all my different trials, everything the same as described in the first post.

*Main LR full range*









-Big room mode at 47 Hz as to be expected

*Main LR with 60 Hz crossover*









-Looks much better than in Post 1

*Sub only, 60 Hz crossover, no EQ*









-Room mode still there

*Sub only, 60 Hz crossover, EQ*









-Now we are getting somewhere

*Sub and mains, 0 phase, with EQ*









-A mess

*Sub and mains, 180 phase, with EQ*









-Still kind of a mess

*Sub and mains, 90 phase, with EQ*









-Looking better

*Sub and mains, 45 phase, with EQ*









-As good as I've been able to get with only having EQ available on the plate amp.

So I don't know if I'm going to get any better than this with the tools I have available. I do feel that from measurements, things look much better than with the main LR alone. I'll have to put in some listening time to verify.

One thing I noticed, having variable phase control made a huge difference in what I was able to do. A simple 0-180 switch wouldn't have gotten me anywhere. I would have had to move the sub all over the room instead.

Hopefully that wasn't too much of an ordeal. I feel like I figured something out. Comments are appreciated.


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## brucek (Apr 11, 2006)

I think it looks pretty good now.


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