Author Topic: Question for those very familiar with REW - An SPL graph  (Read 447 times)

Offline Rick

Question for those very familiar with REW - An SPL graph
« on: April 30, 2019, 09:14:26 PM »
So I finally got a Umik-1 (Actually for a DIY speaker project) but for the heck of it I took two initial sweeps of my listening room with the 0deg calibration file loaded - 0-20Khz, mic in head position one reading pointing at the RHS speaker and the second at the LHS speaker with only that respective speaker active for that reading.

I am still doing a ton of reading and learning here..... as a newbie with this software, where to next, just leave it and enjoy because it sounds just fine to me or should I take more readings and/or look at different graphs in REW?

I am curious as to what the interpretation of the graph below - left and right speaker might show as abnormal if anything, I see a very slight bass bump, but a flattish line from 20hz the speakers are B&W N802, and the room is wall to wall treated with sound absorbing panels.

« Last Edit: April 30, 2019, 09:22:41 PM by Rick »

Offline KenMasters

Re: Question for those very familiar with REW - An SPL graph
« Reply #1 on: April 30, 2019, 09:53:18 PM »
See the little camera at the top left of the graph? You can capture the image as a gif or jpeg - better than photographing the screen.

This is from your listening position, smoothing? Also take a look at the Waterfall graph (you need to hit "generate").
« Last Edit: April 30, 2019, 09:55:33 PM by KenMasters »

Offline Rick

Re: Question for those very familiar with REW - An SPL graph
« Reply #2 on: April 30, 2019, 10:44:08 PM »
Smoothing was 1/6 and mic in listening position yes.

Will do the Waterfall Graph.

Thanks

Offline KenMasters

Re: Question for those very familiar with REW - An SPL graph
« Reply #3 on: May 01, 2019, 08:07:20 AM »
Smoothing was 1/6 and mic in listening position yes.

Will do the Waterfall Graph.

Thanks

Your graph limits are a little generous, with the same on the vertical most graphs would look virtually perfect, this is my system for example:

 

vs a more commonly used vertical axis:



This is also just for display on forums and such, when I'm trying to get a good grip of what's going on I'll use a lot less generous smoothing and also look at my decay times using the waterfall and spectro graphs.


Offline windshear

Re: Question for those very familiar with REW - An SPL graph
« Reply #4 on: May 01, 2019, 09:59:20 PM »
Rick, here is a link to the definitive REW document on the net. Lots of work over many years has gone into it, its long but comprehensive. If you haven't read it I suggest you grab a copy.

https://www.dropbox.com/s/zdhq72a1puyyxpr/REW%20101%20HTS%20Current%20Version.pdf

Offline Shonver

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Re: Question for those very familiar with REW - An SPL graph
« Reply #5 on: May 02, 2019, 07:14:21 AM »
^^^ Thanks for that.
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Offline KenMasters

Re: Question for those very familiar with REW - An SPL graph
« Reply #6 on: May 02, 2019, 09:20:35 AM »
Well, this is a bit of a fluke:

https://www.youtube.com/watch?v=_87-hK1org8

Offline juventino

Re: Question for those very familiar with REW - An SPL graph
« Reply #7 on: May 02, 2019, 10:32:46 AM »
Well, this is a bit of a fluke:

https://www.youtube.com/watch?v=_87-hK1org8

and a very unfortunate surname, pity his middle name didnt start with an S
Time to get back to when I enjoyed listening......no more upgrading, more of a headache than a pleasure

Offline Rick

Re: Question for those very familiar with REW - An SPL graph
« Reply #8 on: May 03, 2019, 06:57:20 PM »
Thanks so much to Ken and Windshear I have a rough idea what I am looking at now. What I have learned is all decay should be around 160ms or less bass traps can be used to get rid of resonances low down, so I tried that.

However walking around with a giant bass trap is making no difference  :o any suggestions as to the data below 20Hz doesn't bother me its the 56-60hz that is...…. rest looks OKish?

Room response 300ms to 20khz


Room response 300ms to 250Hz


Room response 450ms to 250Hz


Raw SPL no smoothing


Variable smoothing SPL


« Last Edit: May 03, 2019, 07:01:40 PM by Rick »

Offline Rick

Re: Question for those very familiar with REW - An SPL graph
« Reply #9 on: May 03, 2019, 06:58:34 PM »
Ok those images are rather small, just click on them will capture larger next time.