# Need a room critique please



## soss (Apr 21, 2014)

This is my first time measuring. I used a UMM-6 USB mic, and did (4) 512k freq sweeps. I recently added some new corner bass traps and wanted to test the difference. You can see two tests in the graph. 

I'm actually appalled at the results. I really don't think my room sounds all that bad. And I thought I had heard a significant improvement with the traps. I'm especially surprised that the traps made no difference to the huge hump in the 30-80hz region.

Any suggestions on what can be done with my room? I suppose I need some more treatment before I even consider EQ'ing, correct?


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

The extreme raggedness you see between ~ 400-4 kHz may be the result of poor measurement technique. The main speakers should be measured one at a time when using REW’s sine wave sweep.

Bass traps don’t necessarily have an effect on frequency response. Their main benefit is reducing low frequency decay times (aka “ringing”), which makes bass sound tighter. That explains the “significant” improvement you’ve heard. The best analytical way to determine any improvement traps might bring is to utilize waterfall graph measurements taken before and after the traps’ installation. 

It takes lots of really big traps to get ringing improvement down in the 30 Hz range, and I don’t think any amount of trapping is going make a significant improvement with a bass peak as severe as what you have at 35 Hz. You’d be better off using parametric equalization for that.

Regards, 
Wayne


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## soss (Apr 21, 2014)

Wayne A. Pflughaupt said:


> The extreme raggedness you see between ~ 400-4 kHz may be the result of poor measurement technique. The main speakers should be measured one at a time when using REW’s sine wave sweep.


Thanks for the response. I'm not sure how to go about measuring one speaker at a time. This is the first time I heard of this. I measured directly between the two speakers in my usual listening spot about 12 feet back front the plane of the speaker's baffles. My room is on the small side.


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

soss said:


> I'm not sure how to go about measuring one speaker at a time.


Use your balance control, or simply unplug one of them.

Regards, 
Wayne


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## soss (Apr 21, 2014)

Should I measure from the same position, or move the mic so that it's directly facing the speaker?


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

I’d put the mic at the listening position and point it at the speaker. :T

Regards, 
Wayne


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## soss (Apr 21, 2014)

Ok, here is left & right speakers measured separately.


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## fokakis1 (Feb 29, 2012)

Soss, that looks like a back wall measurement. Where is your MLP with respect to your room boundaries? What about your speakers?


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## soss (Apr 21, 2014)

MLP= listening position??

I measured from about 20" from the back wall above my couch (my ear level). I have experimented with the loudspeakers' positions, and I believe my Vandersteen 2C's are set up properly for my room- 26" out from front wall, and 14" from the side walls. 

Room Dimensions:

12'W x 14'6"L x 7'10"H
Volume: 1370 sq ft

Thanks for the help.


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## soss (Apr 21, 2014)

Oops, I just remembered I forgot to unplug the speakers cables for each side. I guess I was too focused on getting the mic setup correctly. :doh:


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## fokakis1 (Feb 29, 2012)

Moving your 'Main Listening Position' out from the back wall and/or moving your Steens out slightly should help alleviate some of those spikes.

If this is not an option you can try moving one of your Steens such that your two mains are different distances from their respective boundaries, while remaining the same distance to your mlp. This can keep them from reinforcing the same frequencies. 

You said that they sounded good to you. At the end of the day go with what makes you happy. I'm happy with my humps


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## soss (Apr 21, 2014)

fokakis1 said:


> Moving your 'Main Listening Position' out from the back wall and/or moving your Steens out slightly should help alleviate some of those spikes.


Thanks. 

I'll experiment at 3ft, 4ft, 5ft from mlp and see what I get.


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## soss (Apr 21, 2014)

Ok, this is the left and right speakers measured individually and averaged from 4ft out from the back wall. I don't know if this is more useful to me than the previous measurements, but it definitely _looks_ better. Should I use it? Some of the freq's shifted slightly.


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## soss (Apr 21, 2014)

I tried some EQ filters in JRMC and really like what I heard. Subtle sounds better in my opinion. I wish I could change the color on the "predicted". 

The filters:
44, -8, 2
170, 4, 5
330, 4, 6
690, -3, 3
1375, -2, 6
3000, -1, 2


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## soss (Apr 21, 2014)

Added one more filter:

950, 2, 2

And I cut out the 170hz and 330hz filters b/c they added some bass hardness. Sounds better without them on certain tracks. 

-----------------------------------------------------------------------------------------------------------


I really think I have it now. I think this is the best I have ever heard my system perform. :bigsmile:



*I'm open to any suggestions though.*


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## fokakis1 (Feb 29, 2012)

soss said:


> Added one more filter:
> 
> 950, 2, 2
> 
> ...


I'm glad to see you've made some headway. You moved the mic and eq'd, but have you messed with speaker placement? I always try to improve as much as I can with physics and save EQ for the final touches, if needed.

Keep experimenting. You'll get to know your room and gear intimately.


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## Phillips (Aug 12, 2011)

soss said:


> I tried some EQ filters in JRMC and really like what I heard. Subtle sounds better in my opinion. I wish I could change the color on the "predicted".
> 
> The filters:
> 44, -8, 2
> ...


That null is still large.

Use the RTA in REW for each speaker then combined + (MLP that has already been suggested). After this use the Sweep.

Once you have got the best result post a mdat file containing, left speaker, right speaker then combined.


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## soss (Apr 21, 2014)

Hi Phillips. Thanks for the suggestion. What is the "null" you are talking about? And why use the RTA? In other words, how would that be more helpful?


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## soss (Apr 21, 2014)

fokakis1 said:


> If this is not an option you can try moving one of your Steens such that your two mains are different distances from their respective boundaries, while remaining the same distance to your mlp. This can keep them from reinforcing the same frequencies.



fokakis1, did you mean moving one speaker permanently for listening, or just for testing?


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## fokakis1 (Feb 29, 2012)

soss said:


> fokakis1, did you mean moving one speaker permanently for listening, or just for testing?


Yes.


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## fokakis1 (Feb 29, 2012)

Remember, sound waves cancel and reinforce each other giving you the peaks and nulls you see on your graphs. Having both speakers equidistant from room boundaries can intensify this effect, individually and/or cumulatively. 

While keeping your mains equal distances from your MLP you might try moving them (or just one of them) a few inches at a time and observe the effects. 

From the looks of your sweeps it is likely that you are experiencing boundary gain that is exciting room modes since you have large peaks at frequencies that are double each other. Moving speakers away from walls reduces this effect.


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## Phillips (Aug 12, 2011)

soss said:


> Hi Phillips. Thanks for the suggestion. What is the "null" you are talking about? And why use the RTA? In other words, how would that be more helpful?


The broad dip 

The RTA stands for Real Time Analyzer which enables you to measure in Real Time, great for this then fine tune with the sweep measurements.
With the RTA use the RTA function for each speaker to find the best position for speakers and MLP. This will let you find the affending speaker position. RTA saves your time measuring with the sweep.


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## soss (Apr 21, 2014)

fokakis1 said:


> Remember, sound waves cancel and reinforce each other giving you the peaks and nulls you see on your graphs. Having both speakers equidistant from room boundaries can intensify this effect, individually and/or cumulatively.
> 
> While keeping your mains equal distances from your MLP you might try moving them (or just one of them) a few inches at a time and observe the effects.
> 
> From the looks of your sweeps it is likely that you are experiencing boundary gain that is exciting room modes since you have large peaks at frequencies that are double each other. Moving speakers away from walls reduces this effect.



Ok I moved the left speaker 3 inches forward and the right 2 inches back. There is also a 5 inch differential (24 vs 19) with the side walls (this used to 2 inches). This made a substantial improvement in my sound. Better focus and stereo separation in particular. Very impressed.


Then I did some measurements with L & R individually, L & R averaged, and both speakers with mic pointing directly b/t them. 

The results show some smoothing (although less than I thought).

I'm still trying to figure out the RTA graphs and how to overlay left and right.


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## fokakis1 (Feb 29, 2012)

I'm glad to see you're making progress. Unfortunately, the main speakers are not usually going to be located in a place that is optimal for smooth bass response. Progress, not perfection here.

Do you have a sub?


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## soss (Apr 21, 2014)

fokakis1 said:


> I'm glad to see you're making progress. Unfortunately, the main speakers are not usually going to be located in a place that is optimal for smooth bass response. Progress, not perfection here.
> 
> Do you have a sub?




Yeah, that is exactly what I thought. Which is ok with me b/c it sure doesn't sound bad the way it is now. Do you think by just cutting at 45khz with a peak filter will help the "null" at all? Is there a way to test what a filter does to the overall freq response? (Rather than just show the "predicted" on the chart?)



edit: No, I don't use a subwoofer. A new room and speakers are in my future though. For now I can easily make do with what I have.


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## fokakis1 (Feb 29, 2012)

soss said:


> Yeah, that is exactly what I thought. Which is ok with me b/c it sure doesn't sound bad the way it is now. Do you think by just cutting at 45khz with a peak filter will help the "null" at all? Is there a way to test what a filter does to the overall freq response? (Rather than just show the "predicted" on the chart?)
> 
> edit: No, I don't use a subwoofer. A new room and speakers are in my future though. For now I can easily make do with what I have.


45khz is way out of the range of human hearing. Do you mean "peak" @ 45hz? If so, yes. It is likely that filtering a few db at the target frequency will help tame that peak. 

Simply apply your filter and run a sweep. I like to listen and make notes with my sweeps to be sure my ears confirm what I see on the graph. I use a familiar song with a steady, repetitive bass line that also covers a good frequency range.


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