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REW YouTube Tutorial

138K views 105 replies 40 participants last post by  madermat 
#1 ·
Compliments of GIK Acoustics. We would like to thank GIK Acoustics for preparing a very nice YouTube Tutorial on how to use REW. GIK tells us it is the first of several we can look forward to seeing. Thank you GIK!

 
#35 ·
I'm not a studio guy so I'm not familiar with that equipment - sorry. Basically you need to let the system measure whatever equipment will be used to record and generate the sound by creating a loopback for the calibration.
 
#37 ·
In fact, with a USB microphone, it is a lot simpler
quote from REW 5.01 beta page 28:
The initial steps required to make room measurements are:
1. Choose the audio input and output
2. Calibrate the soundcard (not required when using a USB microphone)
3. Check levels
4. Calibrate the SPL reading (not required when using a USB microphone that has
REW-compatible sensitivity cal data)
 
#44 ·
a generic file could be provided by the manufacturer, not the perfect solution, but better than nothing.
or one could use another PC to produce sound at different frequency and adjusting the level at every frequency using an oscilloscope then record the level on the test sound card, but that would be very time consuming.

So practically, you either use a USB microphone and forget about the error from the input of the sound card or you use a regular microphone and go through the whole process
 
#46 ·
Hello, I couldnt get the program running straight. I did everything step by step. this is a brief video of my problem, if anyone can help i would really appreciate it.
You need to use the beta version of REW to get audio interfaces working properly on the Mac (Apple's version of the Java runtime had a lot of bugs in its audio handling, the beta version has a working Java runtime in it). You can get the beta version here. Note that you need OS X 10.7.3 or later and you should remove REW before you unzip the beta version bundle and drag it into the Applications folder.
 
#51 ·
Thank you for the great program and tutorial as well.

This will allow to do amazing discoveries about chamber resonance and much more.

Best vibes to all, much love and light for all
 
#52 · (Edited)
WOW!! Didn't know that sound was this complicated...

I find the U-Tube presentations very fine... Also the REW docs are easy to get to and a good read...
Looks like another trip to 'DONATE' :wave:

By the several tips already received here it looks like I can keep the small laptop ( portable ) to take with a few patch cords to the hall...
Now to add help to possible good info, I read that a USB i/o for mike out and line in seems very dooable...

Going to U-Tube now to try and find best equipment to fix a room...
Maybe I misread some of the DSP adds, but it sounds like ( no pun ) that a dedicated DSP box just stays in the line to amp. for a most perfect room... Eh??

TNX from DaveR
 
#53 ·
DSP is fine to address frequency related issues. It cannot address reflections or decay time nor can it address modal nulls. Those things need to be addressed by treating the room.
 
#54 ·
OK, and thanks for that, bpape.. Then I take it that a DSP rig or 31 band EQ will do about the same with the exception of maybe the DSP cuts the bands into smaller widths each...
Now I have to ask if there is also a device that will correct for the timing as well??

Unknown territory me me, so TNX again from DaveR
 
#57 ·
DSP is more flexible and it's a parametric vs a graphic fixed type of EQ.

The drawback is that being analog in but providing digital processing, that is adding another A/D and D/A step. Depends on how picky you are bout your sound. If it's just for the LFE channels, it's fine. Personally, I wouldn't put something like that on my main channels.

There are also all analog parametric EQ's available - just that you have to do the tweaking yourself as opposed to running a sweep and letting the unit make the changes (which I'm not really fond of anyway - but that's just my opinion).
 
#58 ·
TNX much Bryan,

That sets me in the right direction and I am greatful for your advice.
Right now it looks like staying with the 31 band mono EQ set for the only room that it will be playing in, and possibly something like a feedback destroyer down stream of the manual EQ just to take care of any 'surprizes'...

DaveR
 
#60 ·
Hi Bryan! Sorry you haven't heard from me this week. This is part of why :).

I've been attempting to use the DBX M mic that comes with the DBX Driverack. By all accounts it's an omni mic made for doing measurements. I'm following the GIK-supplied video (much thanks!). The problem I'm having is that when I attempt to do the initial soundcard calibration I'm getting an error telling me that the level is varying by way too much - typically 57db and that I shouldn't use the calibration created.

I'm on Mac OSX 10.9.5 using an old RME Fireface. The Fireface has a software mixer (Totalmix) which allows for creating loopbacks. I've checked VERY carefully and repeatedly that I'm not accidentally looping the output to the input. When I get the initial input level calibration anywhere close to the output level - the resulting sweep measurement clips. I have to have it about 20db lower than the output to make the sweep stay in the green.

BTW, I tried selected the actual (ASIO) driver for the Fireface and the level variation was a LOT higher. in the 90's.

If it matters, my monitoring system is a presonus central station feeding a JBL subwoofer which in turn is feeding a pair Quested v2108 speakers.

Any help would be greatly appreciated. Thanks so much in advance for the great software and the assistance!

Pier Giacalone
 

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#62 ·
I'm not a Mac guy so really can't help much. Not familiar with that microphone. That said, I've never done a mic calibration. As long as the mic is decent, you shouldn't have to. We really don't care if the very top or bottom end are down a couple of db. We're looking for relative variation and relative change as seating, speakers, and subs are moved in the room to get the best starting point and identify the frequencies at which problems occur. Don't really care if that null at 120Hz is -10db or -12db - just that it's a null and it's at 120Hz.

Wish I could help with your issue but I wouldn't let that hold up measuring as long as you can get a good reading. It will be pretty clear in the measurement if it looks to be a valid one or not.
 
#64 ·
I'll try that. I figured since I'm having trouble following the directions in the video it applied, but I'm happy to try whatever will lead to fixing the problem. I was also working directly with Bryan before I even found this thread.

Bryan. I tried it on PC as well. Same issue. I also tried it on a different mic. Same issue. I'm pretty stumped. I'm getting a fairly consistent reading though so, I guess it's ok. I'm still learning how to read all the different data.

I'll try starting a new thread.

BTW - I found the video moved a bit too fast too :).
 
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