REW help reading graphs

[babgrip]

New to REW and could use some help reading the results of test.
Dedicated 2 channel listening room w/ the following treatment.
4- Diaphragmatic bass traps in corners
Quadratic diffusers FT+ R walls
Quadratic diffusers and O.C.-703 absorbers side walls
Test done with zero eq
Sounds good with tone control + sub
Main complaint is huge bass mode along side walls and lack of bass at listening position.
Have tried and tried different speaker and listening position
Speakers are KEF R107

 

[kemmler3D]

The decay times look good, arguably maybe even too short in the treble region.

There seems to be a 60-cycle hum coming in somewhere.

The frequency response looks overall much more ragged than I would expect based on your treatment and speakers. It's possible you are over-absorbing around 2khz and maybe 400hz. Was the mic placed close to the QRDs? It also looks like you have too little upper treble above 6khz, depending on how much OC703 you have, this might be why.

You definitely have some room modes, same as everybody, which I would definitely suggest knocking down with EQ.

Overall the RT60 looks enviable but (to my eye) overdamped above 6khz and I am not sure what to make of the dip around 2khz. Bass looks well controlled until you get below 80hz, at which point I'd suggest EQ.

My questions are: what mic are you using? Where was it placed? The dips around 400, 1K and 2K are a bit puzzling.

If you are able to share an .mdat file here, other members can load up your measurements and poke around themselves.

BTW welcome to ASR!

 

[marin.weigel]

My guess is that the measurement was taken with a fixed mic position, and if so, measuring L+R simultaneously with slightly different distances to the tweeters in even the low millimeter range, will yield weird phase cancellations in the high frequency range.
Looking at the impulse or energy time responses will likely show the different arrival times from both tweeters.
That said, it's better to measure each channel separately.

 

[kemmler3D]

My guess is that the measurement was taken with a fixed mic position, and if so, measuring L+R simultaneously with slightly different distances to the tweeters in even the low millimeter range, will yield weird phase cancellations in the high frequency range.
Looking at the impulse or energy time responses will likely show the different arrival times from both tweeters.
That said, it's better to measure each channel separately.

Good point, this could explain the dips at ~425 and 950hz (maybe? would need to be about 30cm difference in distance?) but (maybe I am off base here) to me the dip at 2300hz looks too broad for that...

 

[marin.weigel]

I'm rather talking about the plummeting beyond 7kHz.
Let's see what individual measurements reveal, before we start reading tea leaves.
I'd like to see impulse, energy time and step responses out to 15 or 20 ms, in addition to the common plots for each channel separately, maybe an upload of the mdat files to play with them.

 

[Sokel]

Here's all you need to start:

Taking and Interpreting Measurements with REW (FREE eBook)

A few years ago, Amir wrote Room Measurement Tutorial for Dummies Part 1 and Part 2. The third part has never materialized despite many requests. In the meantime, there is a clear need for clear guide on how to take room measurements because we are seeing more and more people take and post their...

www.audiosciencereview.com

(it would help to put FR chart at 50dB range, 20dB as is now is hardcore! )

 

[babgrip]

Yes, One combined L+R measurement from the listening position using Daytonaudio UMM-6
I will take separate measurements tomorrow with FR set to 50db

 

[staticV3]

Please use Moving Microphone Method for in-room frequency response:

The moving microphone method (MMM) for Dummies using REW

After getting a couple of weird results on my first MMM measurements, I went searching around the forums & YouTube for what went wrong. To save others from gathering various bits and pieces of info from a dozen sources, I decided to publish this quick write-up here. You can use it as a rough...

www.audiosciencereview.com

Also no additional smoothing applied besides the 1/48 Oct dictated by REW's RTA.