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Measuring Room Acoustics
Old 27th October 2011
  #61
Here for the gear
 

where I can find the primer v2.1, I try to find a link but I can't

please help me
Old 27th October 2011
  #62
Gear Guru
Dead Links

You are in the thread, go to the first page top if you can. There may be a problem with links within GS. Another one failed elsewhere yesterday.
Here's what you asked for anyway, hope it works.
https://www.gearslutz.com/board/studi...er-v2-1-a.html
DD
Old 13th November 2011
  #63
Gear Maniac
 

Hi dandan or anybody. question about measuring. Ive hardly heard anybody mention about the speaker used in measuring. How important is it to use a very flat studio monitor versus a cheap Hi-Fi/desktop speakers? will the use of the cheap desktop speaker not give accurate results as to room measurements?
Old 29th November 2011
  #64
Gear Maniac
 
aackthpt's Avatar
 

Quote:
Originally Posted by Chris_Nicks View Post
Hi dandan or anybody. question about measuring. Ive hardly heard anybody mention about the speaker used in measuring. How important is it to use a very flat studio monitor versus a cheap Hi-Fi/desktop speakers? will the use of the cheap desktop speaker not give accurate results as to room measurements?
Firstly, most speakers are going to be very flat compared to most rooms, so the speaker is usually not the most important factor. Secondly, the speaker and room are a system - you don't listen to only the room, you listen to the speakers in the room. Therefore you test the speakers and the room together, and when you change something (like speakers) you should remeasure the system.

If you want to comparatively test speakers independent of a room, you need to use different procedures that are not detailed in this thread.
Old 13th March 2012
  #65
Lives for gear
 
hereticskeptic's Avatar
I'm getting pop-up messages/error messages every time I try to measure using REW. Is there any chance someone would be willing to help me troubleshoot what I might be doing wrong? I have a graph, but have no idea if it has been done properly, and REW certainly doesn't seem to think so.

I currently have a 75dB SPL reading at the mic's position, which is exactly where my head would be, at the exact height my ears would be. The mic is pointing at the left monitor. What else needs to be done/checked before a proper reading can be measured? Thanks in advance.
Old 13th March 2012
  #66
Gear Guru
REW Learning Curve

Apart from the fairly steep learning curve, there are issues.
REW doesn't work with multichannel interfaces on Mac computers.
If you have a Mac and anything other than a simple stereo interface, omit that I/O and use the onboard Line In and Out. They are of decent quality.
So heretic, are you on a Mac? What does the error message say? A screengrab or snapshot AppleShift3 perhaps.
DD
Old 13th March 2012
  #67
Lives for gear
 
hereticskeptic's Avatar
Quote:
Originally Posted by DanDan View Post
Apart from the fairly steep learning curve, there are issues.
REW doesn't work with multichannel interfaces on Mac computers.
If you have a Mac and anything other than a simple stereo interface, omit that I/O and use the onboard Line In and Out. They are of decent quality.
So heretic, are you on a Mac? What does the error message say? A screengrab or snapshot AppleShift3 perhaps.
DD
Oh okay. Yeah, I am using a Mac and a Metric Halo ULN-2 interface, which has digital i/o, but only two analog input channels and 4 analog output channels. Will this work, or should I use Fuzz Measure to avoid issues? The error messages have been different, but I've attached a screen shot of the current one. Thanks for the reply DanDan!
Attached Thumbnails
Measuring Room Acoustics-screen-shot-2012-03-13-3.25.26-pm.jpg  
Old 14th March 2012
  #68
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hereticskeptic's Avatar
Here's a response graph I just took where two different messages popped up. The second of the two messages is the same as in my prior post, but this time it followed the first message in this post, after selecting "OK" for the first message. In other words, even when my input volume level is above -10dbFS, I'm still not meeting the requirements to get a suitable impulse peak response. The input volume goes above -10dBFS when I turn the interface preamp gain up, but I still get that impulse peak error message.
Attached Thumbnails
Measuring Room Acoustics-screen-shot-2012-03-13-3.57.51-pm.jpg   Measuring Room Acoustics-screen-shot-2012-03-13-3.57.57-pm.jpg  
Old 14th March 2012
  #69
Gear Guru
Peak

You are welcome. The 4 outs probably qualifies the interface as multichannel. The fault lies with Apple not doing Java correctly for multi. I had a lovely Lexicon iONIX which I found unusable. The same error message about the IR peak not being in the right place. But more importantly weird unusable readings. I believe you can use the Output of such interfaces, which saves some wiring, monitor controllers etc. However, the inputs will be unusable. Use the onboard Mac Line Input and an external Mic pre. If there is a H/W insert on your interface you could use this as a Direct Out.
Persist, REW is very very good.

DD
Old 14th March 2012
  #70
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hereticskeptic's Avatar
I did a bunch of measurements in FuzzMeasure, and am pretty sure I got that working fine. I shut the cpu down for the day, but could post those if that's cool. Should I just upload jpeg files, or something else?
Old 14th March 2012
  #71
Gear Guru
Consult

FM is pure Mac, works every time. You can export the IR and then examine them in REW using it's (superior) tools.
If the file is not too big, you could Zip it and post it here.
However, this thread is long. Unless there is a measurement anomaly or detail of interest please PM or email me via the direct email on my website,, with queries about the measurement.
I will happily help you personally.
DD
Old 23rd March 2012
  #72
Gear Head
 

This was a damn good read. Thanks for writing all that down!
Old 18th April 2012
  #73
Gear Nut
 

great article

thanks !!
Old 3rd May 2012
  #74
Here for the gear
 

give thanks dan, awesome stuff..

am just going into studio today to do a test for my studies and when I read through this a couple of weeks back it was most beneficial.. any ideas when you will have v3 ready as I anticipate your excellence in this field..
Old 6th May 2012
  #75
Old 28th May 2012
  #76
Gear Maniac
 

Hi DD. Thanks so much for posting V.3. Now I understand what you mean by...PRIMER...DOH!

Ok, I do have a question. Like I said, I've purchased a measurement mic. Not the best in the world, but according to Ethan, it'll work...at least for us HR guys. However, it'll be a week before it gets here, and I'd sure like to try this REW stuff out. I have a Rode NT2 large condenser, with an Omni switch. Will this work? Thanks.

Oh, does the room have to be empty. I have a ton of audio gear(4 R2R, console, consumer playback gear etc..in racks.

Oh, another one. Should I use the speakers in the soffets, or the nearfields on my console?
Old 29th May 2012
  #77
Gear Guru
Go for it

Rode will be fine in Omni. Room as it is or will be is best. Drive just one speaker as described, then the other, then both if you wish. I will get into that and other detail as time goes by. In the meantime it is good to become familiar with driving the software.
It gets easier.

DD
Old 4th June 2012
  #78
Gear Maniac
 

thanks for the post! Were can i download this program to mesure my audio IR?
Old 4th June 2012
  #79
Old 16th November 2012
  #80
Gear Guru
Pointing the Mic

A confusing Topic which keeps coming up. Similar to the Two speakers thing.
We see recommendations on websites to point the mic upwards and to drive both speakers.
Both are valid, but only in exceptional contexts.
It is normal to point a Free Field mic at the source of interest. Dual sources can be very confusing, especially when reflections are being considered.

Most of the common measurement mics are Free (Direct) Field. They are at their best pointed Directly at the object of interest.

The Cal File which comes free with each individual Dayton EMM6 corrects (calibrates) the response to flat when the mic is used On Axis in a Free/Direct/Near Field.
EDIT, it appears they now supply three Cal files 0/45/90 degrees. How perfect.
Similarly the UMIK-1 from MiniDSP comes with a Cal file specific to the actual mic supplied.
Given the small price of either of these, it really does not get any better than this.

The generic Cal Files for the ECM8000 at REW try to do the same job using a generic response averaged over several actual mics.
Home Theater Forum and Systems - HomeTheaterShack.com
These generalised files clearly cannot deal with individual mic variations which are far from the average.


The Dayton and MiniDSP are clearly better choices.

The most accurate response for the UMIK and the Dayton (using the 0 degree Cal file) will be Mic horizontal, pointing at the area of source of most interest.
The Dayton has the advantage that you can point it upwards to hear the rooms and speakers more equally (e.g. for 5.1) but still get decently flat response by using the 90 Degree Cal File.

Exceptional Circumstances
For simple L/R or Surround Level balance, it is convenient to point up (or down if carpeted). This will (mis) treat all incoming horizontal HF equally. Pink Noise and an SLM are also convenient for this work. REW provides these.

Mics in USA ANSI standard SLMs are designed for Diffuse Field. There are very few standalone Diffuse Field measuring mics. When using a Diffuse Field mic, follow the instructions, point it upwards, perhaps leaning towards the source, e.g. 70-80 degrees.

Confusingly, the FR graphs seen in advertising for the ECM8000 suggest that it should be quite flat up to 10K when pointed upwards.
The problem with this mic is the differences seen between individual mics, as seen in the above HTS link.
EDIT A GS has recently tested an 'original' vs a new ECM. The new one has a very wild response.

DD

Last edited by DanDan; 4th December 2012 at 03:27 PM.. Reason: Continued Mic pointed confusion
Old 27th March 2013
  #81
Gear Nut
 
mistergreen's Avatar
Is anyone using REW on a standalone (no internet) PC? I am having trouble installing it. It keeps trying to connect to the internet to look for JRE. I removed JRE7 and installed JRE6 with no success.
Old 28th March 2013
  #82
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Rod Gervais's Avatar
 

I use it without connection to the internet.... have never had an issue...

Rod
Old 26th May 2013
  #83
Here for the gear
 

Hi,
Quick question. I bought UMIK-1 to use it with Room EQ Wizard (REW). My question is that do I also need an SPL meter to do proper measurements?

I tried to use REW wihout calibarating the mic and REW gave me a message that the SPL is too low. I figured this was probably due to fact that I didn't calibrate the mic.

Thanks!


-Tony
Old 26th May 2013
  #84
Gear Guru
Calibrated

I don't have a UMIK-1, but I have been watching it's progress. I believe the current ones are very different from the original.
The Calibration information associated with each actual mic includes absolute level. i.e. at the factory they have measured the sensitivity of each mic. So if REW is given the Cal info, the onboard SPL meter should read real levels. You will need to read the REW or UMIK manuals to be sure they are communicating fully. There is a wrinkle. I have been told that there are internal gain changing switches in the UMIK. So I guess you have to be aware of what setting is at play, and tell that to REW in some way.
DD
Old 26th May 2013
  #85
Here for the gear
 

Hi DanDan,
And thanks a lot! After downloading the calibration file from UMIK-1's website the system seems to be ready to go. All that was needed was to import the calibration file and to define the correct input device at the preferences of REW. In my case (Linux) the correct input device was named U12db.

It's night here, so I have to wait for tomorrow to start measuring. I'm quite excited about beginning the measurements


-Tony
Old 4th August 2013
  #86
Here for the gear
 

Hi Dan, I see im jumping on this thread a little late. thank you very much for posting this info and for being so helpful in helping out with my dilemma!

-Suniel
Old 1st September 2013
  #87
Gear Head
 

Thank you very much Dan ! Very interesting !
Old 11th February 2014
  #88
Gear Guru
UMIK

Unfortunately I can't edit the Sticky to keep up with developments so.
I cannot get the UMIK-1 and REW to function successfully on a Mac.
And. Good news. .mdat Files can now be posted directly using the Manage Attachments paperclip tool.

DD
Old 23rd February 2014
  #89
Gear Head
 

Quote:
Originally Posted by DanDan View Post
I cannot get the UMIK-1 and REW to function successfully on a Mac.
Is FM the only solution?
Old 23rd February 2014
  #90
Gear Guru
Two

No. FM is a proper Mac program, it will work exactly as it says on the tin. REW will also work perfectly well if you use the Line In and Out of the Mac.
The UMIK is naturally or natively or solely a 48K device. This causes further problems with the Mac OS. But again, the onboard Mac hardware works perfectly.
DD
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