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Room Frequency Reponse- 1st shot
Old 23rd October 2013
  #1
Gear Head
 
Cuzzin Chizzy's Avatar
 

Room Frequency Reponse- 1st shot

I recently tested my rooms frequency response using Room EQ Wizard and a Behringer ECM8000. I am now looking for some guidance on what to look for in the REW test measurement graphs to help me select the type and quantity of bass traps necessary to finish my rooms treatment.

I've included the first SPL and waterfall graphs and as attachments.

Any and all input is greatly appreciated!



P.S. A couple things that would help tremendously...

Can anyone tell me why the higher frequencies are cut off on the graph? I left the measurement setting at default.

I was unable to upload the REW .mdat file onto these here forums. Any ideas on how to accomplish that?



Thanks again!
Attached Thumbnails
Room Frequency Reponse- 1st shot-test-1.jpg   Room Frequency Reponse- 1st shot-waterfall-1.jpg  
Old 23rd October 2013
  #2
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sheggs's Avatar
Did you get a chance to watch our video on REW before testing? Room EQ Wizard Tutorial - GIK Acoustics
Old 23rd October 2013
  #3
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Cuzzin Chizzy's Avatar
 

Yes, that is the tutorial I followed for setting everything up. I did the sound card calibration creating a loopback with my 1616m. I checked levels and then calibrated. The sweeping wave during testing started very low and then went to high. I have two Yamaha HS50Ms and an HS10W sub.

In order to run the speakers in stereo for the test I had to set the audio driver output to the left speaker and the timing output option to the right(don't remember exactly what it was called but it should show up as an option in REW assuming you're using an ASIO driver)
Old 23rd October 2013
  #4
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spiderman's Avatar
Check the tutorial again.... You'll notice that GIK's settings generate test results from 20Hz to 22kHz. You test is the default REW settings which only display up to 400Hz. You'll need to change your testing parameters and then measure again...
Old 23rd October 2013
  #5
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jim1961's Avatar
 

When you redo things show us about 50db of range, not 240db for the frequency response. Change divisions to 5db, instead of 20db.
Old 23rd October 2013
  #6
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Glenn Kuras's Avatar
Quote:
Originally Posted by spiderman View Post
Check the tutorial again.... You'll notice that GIK's settings generate test results from 20Hz to 22kHz. You test is the default REW settings which only display up to 400Hz. You'll need to change your testing parameters and then measure again...


You might want to test then zip the REW file and post it. We can then open it up in our own program to view it. Also make sure to test one speaker at a time then both.
Old 24th October 2013
  #7
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Cuzzin Chizzy's Avatar
 

First of all.... Thanks to everybody for their input!

I plan on retesting my setup tonight using the information given, and should be able to get a more accurate and full test as well as the .mdat file.

There are a few things that would be nice to be enlightened on as well...

What is the purpose of the eq switches on the back of my Yamaha setup? HS50M & HS10W in 2.1. Wouldn't changing the eq take away from the accuracy (flatness) of the monitors by coloring the frequency response?


I read somewhere about one reason why the eq switches would be helpful.. To use as a crossover around 80 hz. Making sure that you don't have monitors and sub stacking the same frequencies. Is that the reason for these controls?

Would this be a good plan and order?
1. Adjust speakers to crossover at around 80Hz.

2.Test room frequency response using REW, and problem areas with an SPL meter.

3. Finish sound treatment accordingly.( most likely adding bass traps)

4. Adjust speaker eq to help with any problems left over ...?


The eq thing is kind of confusing to me.
Old 25th October 2013
  #8
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I would test first without any EQ and sans sub. Just the main pair running flat.... several tests with various mic placement adjustments.
Then run a test with sub.
The run a test with sub and crossover switches.

Compare everything.... try moving the sub and test again.
Old 25th October 2013
  #9
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AwwDeOhh's Avatar
 

Quote:
Originally Posted by Glenn Kuras View Post


You might want to test then zip the REW file and post it. We can then open it up in our own problem to view it. Also make sure to test one speaker at a time then both.
lol
Old 27th October 2013
  #10
Gear Head
 
Cuzzin Chizzy's Avatar
 

How do I message a moderator. The site will not let me upload a .zip file with all of my .mdat files.

It tells me to message a moderator after the upload fails but the link doesn't work.
Old 28th October 2013
  #11
Gear Guru
Too Big

There is a limit of about 10MB on upload file size. Even when Zipped .mdat and FM files are frequently bigger than that. It would be great if GS could accept those files directly and larger. I will ask Gearbot about this.
DD
Old 28th October 2013
  #12
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Glenn Kuras's Avatar
Quote:
Originally Posted by AwwDeOhh View Post
lol

Thanks.. Just did a edit.
Old 29th October 2013
  #13
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Cuzzin Chizzy's Avatar
 

I tried decreasing the file size of the .zip file to under the max upload of 9.54MB and now am getting an upload error that says my .zip is an invalid file.

I took around 10 different measurements that REW saves as .mdat files. I then group them and archived them with WinRAR to files about 7MB and 9MB.

But still get that upload error, invalid file. Any ideas?
Old 29th October 2013
  #14
Gear Guru
Stalled

I am not familiar with PCs. I suggest you try a test. Take an .mdat file with just one measurement in it. Zip it alone, check that it is under 9.54MB, then try to post it. I have linked Gearbot to this thread as this File upload is a common problem here.
DD
Old 29th October 2013
  #15
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akebrake's Avatar
 

Quote:
Originally Posted by Cuzzin Chizzy View Post

Can anyone tell me why the higher frequencies are cut off on the graph? I left the measurement setting at default.
Hi Chizzy,

seems like the default set up is suited for a sub, so just change that to mains and full spectrum.

Quote:
I was unable to upload the REW .mdat file onto these here forums. Any ideas on how to accomplish that?
One way to work around the problem (with large .mdat files) is to export each of your measurement as a wav file. As in this link below:

https://www.gearslutz.com/board/9113114-post16.html

For a start: Take Left speaker IR, Right speaker IR and Sub IR in a typical situation.

BTW Tell us more about your plans!

Cheers

Ake
Old 30th October 2013
  #16
Gear Head
 
Cuzzin Chizzy's Avatar
 

Okay, got it figured out. Apparently the Gearslutz upload tool isn't a fan of .rar files. The .zip files (which I thought I originally did, but did not use) work perfectly.

I've included all the measurement .mdat files I generated in REW as well as the impulse response wave files as per akebrake's post.

I plan on finishing an album I've been recording for a while now. It will be nice to have the added accuracy of a better treated room when mixing and mastering.
Attached Files
File Type: zip REW measurements IRwav.zip (713.0 KB, 23 views) File Type: zip REW measurements mdat-1.zip (7.74 MB, 27 views) File Type: zip REW measurements mdat-2.zip (5.76 MB, 23 views) File Type: zip REW measurements mdat-3.zip (7.82 MB, 96 views)
Old 31st October 2013
  #17
Gear Guru
 
Glenn Kuras's Avatar
You may want list some details about the room with a either some pictures and or a layout. Also it really helps to keep all the tests in one REW file.
Old 31st October 2013
  #18
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akebrake's Avatar
 

Quote:
Originally Posted by Glenn Kuras View Post
..... Also it really helps to keep all the tests in one REW file.
Don't you think that this will result in a file larger than 10 Mb?

Ake
Old 1st November 2013
  #19
Gear Head
 
Cuzzin Chizzy's Avatar
 

This thread has all the details about my room.

What should I do with my room?!

I do also believe as akebrake said that the REW files, if all were put in one zip file, would be too big to upload. Unless there is a way within REW to save all measurements as a group at a smaller file size?
Old 1st November 2013
  #20
Gear Guru
File handling

Posting both pictures and files has become a real chore, unsuccessful in the case of the small unreadable graphs, and often unsuccessful or tedious for acoustic measurements.
Because of the 9.54 MB limit REW or FM files containing multiple measurements are too big, so we have to split as seen here. Note they can easily be opened in a single REW.
Exported IR's have the same issue, one per measurement.


Mods- please allow .mdat as a file format (perhaps FuzzMeasure too) and increase the limit to 20MB for .mdat, Fume, and Zip.


DD
Old 1st November 2013
  #21
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AwwDeOhh's Avatar
 

FYI, in the meantime. If you have 2 instances of REW open, you can drag-drop measurements into eachother.
or
you can drag an additional .mdat file into an open instance of REW and it will append all the measures into your open window.

(still doesn't help the file issue here, but in case anyone didn't know!)
Old 2nd November 2013
  #22
Gear Guru
 
Glenn Kuras's Avatar
Quote:
Posting both pictures and files has become a real chore
So is exporting someones IR files to then go back and import.

Quote:
Mods- please allow .mdat as a file format (perhaps FuzzMeasure too) and increase the limit to 20MB for .mdat, Fume, and Zip.
Would be nice.


BTW if you would make one file from the OP's tests and email it to me that would be great.
Old 3rd November 2013
  #23
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Mctwins's Avatar
 

Quote:
Originally Posted by Cuzzin Chizzy View Post
Okay, got it figured out. Apparently the Gearslutz upload tool isn't a fan of .rar files. The .zip files (which I thought I originally did, but did not use) work perfectly.

I've included all the measurement .mdat files I generated in REW as well as the impulse response wave files as per akebrake's post.

I plan on finishing an album I've been recording for a while now. It will be nice to have the added accuracy of a better treated room when mixing and mastering.
Hallo

Your Filtered Impulse response dosen't look good with the sub compare to without sub. You have to change/set your level before measurement with the sub, look at the scope graph right after a measurement has been done and see if the signal is not clipping. If so, then the measurement is not valid, as can be seen on the Curvature where you have around 52%. Your mdat-1 file

Last edited by Mctwins; 3rd November 2013 at 10:59 AM.. Reason: adding text
Old 3rd November 2013
  #24
Gear Guru
All in One

I just tried combining all those single measurements in on REW window.
The simplest way seems to be drag and drop them into an open REW session.
Unfortunately when I select all and try to drag them all simultaneously, various error messages come up. To be fully sure I did them one by one.
The full collection should be available for download here https://dl.dropboxusercontent.com/u/...Glenn.mdat.zip
DD
Old 5th November 2013
  #25
Gear Head
 
Cuzzin Chizzy's Avatar
 

Quote:
Originally Posted by Mctwins View Post
Hallo

Your Filtered Impulse response dosen't look good with the sub compare to without sub. You have to change/set your level before measurement with the sub, look at the scope graph right after a measurement has been done and see if the signal is not clipping. If so, then the measurement is not valid, as can be seen on the Curvature where you have around 52%. Your mdat-1 file

I'm not sure I understand what you meant here. I set the monitor volume knobs to 12 o'clock and the sub to 10 o'clock as specified in the Yamaha HS series manual.

Please keep in mind, I'm a total noob when it comes to this stuff. That's why I came here. To understand what it is I'm even looking for on the measurement charts and to be able to read them with more understanding.

Ultimate goal is just better room response.
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