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Help with REW SPL Graphs - First time user

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pimogo

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So still experimenting but have a new question if anyone has any theories...

I'm trying to arrive at a system of measurements that is consistent time and time again so i was interested immediately when i read about the moving mic method.

To test it out i first did a set of static microphone measurements, averaged that and set it aside. Using all the same gain settings I then ran RTA using the settings below and noticed that while the pattern is similar, there is a ~20 db difference between the two. I tried this several times w/ the same result. My assumption would be they would be close to each other, perhaps even identical (ideally). What would account for that difference? The results just factor the Left speaker. The bottom plotted line is the moving mic measurement , the top is the static..



MMM.jpg
MMM settings.jpg

1651777129827.png

1651777259925.png
 

Rednaxela

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Could you perhaps match the axes of the two graph images? Struggling to compare the two.
 

Erici

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Brilliant! That was it! Many thanks.

Crude and quick, but i get the lines to line up. Perfect.. have a weekend of measuring ahead of me. :)

View attachment 204758

I like the MMM approach too. It's really fast and effective.
It's also important to measure each channel separately and EQ each individually. They may have very frequency responses. At least measure each to be sure they're close.
 
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pimogo

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Took a hiatus but now back for further room acoustic analysis-- this time on my main system. A pair of Forte IVs. Any guidance gladly appreciated as a lot of this is still new to me.

Using a Umik-1 with calibrated 90 degree file, I began my measurements by pointing away from the speakers from about the listening spot using the moving mic method I learned from watching this video, I took several measurements.

I started w/ taking measurements of each speaker first (L and R) and then comparing those measurements to the composite measurement of L&R together, seen below.

REW Preferences:

Preferences.PNG


Generator Settings
Generator.PNG


Using those settings, I generated the following set of measurements....

Measurements with 1/24 Smoothing

Measurements - All.jpg



Average
Average.jpg


Now is the part I probably need the most help with! Creating a set of filters from these measurement so I can plug into ROON. I took a stab as follows, but please correct me if I'm wrong. Watching several videos on the topic helped but also confused to an extent as everyone tends to use their own preferred settings.

EQ Settings-
EQ Settings.PNG


Settings i changed were:
1. Generic
2. Full range Speakers
3. I hit the 'Calculate target level from response' to get the curve to overlap the house curve. Yes , I'm using a harman house curve for this example.
4. Match range 38 to 20,000 (my fortes only go down to 38 so i figured i would cap it there)

With those settings in tow, I hit the 'match response to target'.


That yielded the following:
EQ output1.jpg


Questions:
Should i be using Full Range Speakers?
What should I try next to create better picture of my room?

The PEQ it generated yielded several high Q filters.
eq output2.PNG




Again, i've gotten this far because of the invaluable feedback from this group, so thank you again!

-H
 

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  • Average.jpg
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  • Measurements - All.jpg
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pimogo

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Can someone help explain what could cause this imbalance (after ~4k) between the left and right channel. Both measurements were obtained using the moving mic method around the listening position. Is this normal or something to be concerned with?



Channel Imabalance.jpg

I sent a signal to each speaker using Rew's Generator. I set the Output to L , captured my measurement; then i did the same for R.
 
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Rednaxela

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Perhaps swap the speakers and see what happens?
 

Rednaxela

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Just to check if your left speaker might be notoriously brighter.
 
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pimogo

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Just to check if your left speaker might be notoriously brighter.
So i ran several more measurements after swapping the speakers. No change. Left still 1+ dB brighter . I then changed the speaker wire for both speakers, but the same pattern emerged. Left is brighter by 1+ dBs in all scenarios.

Would the windows on the right hand side of the room (3 floor to ceiling windows) have anything do to w/ the difference. I suppose i can the balance to even it out some, but any other theories as to what might be happening here?

Thanks!
 
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