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Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs

2M views 38K replies 1K participants last post by  LastButNotLeast 
#1 · (Edited)
The purpose of this thread is to explain how to both physically hook up the connections between your computer and AVR/Pre-Pro to get started with REW (Room EQ Wizard) and to share information on the proper use of REW including proper techniques for both measuring and interpreting graphs, what you should be looking for in each graph, how to fix problems using room treatment, speaker placement, listener placement, and other tweaks, both before and after EQ, and delve more into topics not often talked about which when dealt with properly can drastically change (for the better) your listening experience to become true audio nirvana.

I highly recommended reviewing the very thorough guide created by AustinJerry (My heartfelt thanks to you, Jerry, for taking the time and effort to put this together and keep it updated) which contains information contributed by myself and many other AVS'ers on both how to connect your equipment and how to use REW in (post 275).
 
#12,021 ·
This only affects those who use the sensitivity parameter, rather than performing a manual calibration against an external reference such as a SPL meter. I have always advocated manual calibration, so I personally have not been affected by this bug. And even with the fix, a manual calibration is always more reliable and accurate, IMO.
Hey Jerry , can you describe how to do a manual calibration, or post a link?
 
#12,023 ·
One highlight from the release notes meaning it is highly relevant to people here

Bug fix: SPL readings from USB mics were 6 dB low (verified on UMIK-1, suspected to affect Omnimic and UMM-6 also).
I guess that would explain why Audyssey kept knocking my levels down so dramatically after I had run an initial "calibration" via REW. :eek:

And to think I initially blamed my Onkyo 805's atrocious puck microphone. I'm sorry Onkyo, I should never have doubted you. ;)
 
#12,025 · (Edited)
For those who haven't already, check out the document linked to in the recent SMPTE thread. [ http://survey.constantcontact.com/survey/a07e9y6vd10i0zj9i4f/start ] I think there's lots of info that many here would find interesting. Not relevatory probably for some, but useful probably for most of us. Might help in determining how and what we measure, maybe how we set up our analysis/measuring windows, etc. For instance, if you look starting at p56 there are some charts and graphs that will maybe tease you to read more...
 
#12,026 ·
The REW Guide has been updated to version 3.9, October 21, 2014

Changes:

3.9 October 21, 2014 - Several minor revisions to the “pre-out” measurement instructions.

Jerry sorry to say because of some unforeseen problems I have not run REW yet, I plan on really giving this my best when I'm totally convicted to doing so. Could you tell me where in the guide the revisions have been made (particular pages). I have the original downloaded on my PC and printed the pages from that so I can do the actual REW procedure on my laptop. I think I have 38 pages printed out now so I would really appreciate if you could give me an idea of the pages that have the revisions. Thank you for the time and effort to provide this guide to those of us novices.
Sincerely, Jeff
 
#12,027 ·
Jerry sorry to say because of some unforeseen problems I have not run REW yet, I plan on really giving this my best when I'm totally convicted to doing so. Could you tell me where in the guide the revisions have been made (particular pages). I have the original downloaded on my PC and printed the pages from that so I can do the actual REW procedure on my laptop. I think I have 38 pages printed out now so I would really appreciate if you could give me an idea of the pages that have the revisions. Thank you for the time and effort to provide this guide to those of us novices.
Sincerely, Jeff
The changes were made in the section titled "Pre-out measurements". You can get the page numbers from the index.
 
#12,028 · (Edited)
#12,031 ·
I'm the kind of guy who doesn't want to feel as though I'm missing something. I think it sounds great, I just want it to be dialed in.
Personally, I would be concerned with the 15-20dB rise as the curve approaches 20Hz. If this is an intentional house curve, then that is fine. Otherwise, I would be working to flatten it out. Perhaps you can post a waterfall graph to see how the rising low frequency response affects bass ringing. Also, an ETC graph would allow us to see how well you have controlled room reflections.
 
#12,032 ·
Personally, I would be concerned with the 15-20dB rise as the curve approaches 20Hz. If this is an intentional house curve, then that is fine. Otherwise, I would be working to flatten it out. Perhaps you can post a waterfall graph to see how the rising low frequency response affects bass ringing. Also, an ETC graph would allow us to see how well you have controlled room reflections.
Guys, excuse my ignorance but I'm really new to REW, I opened the program today and upon opening it said a newer version is available, version V5.01 Beta 23, it mentions inprovements in certain areas and certain bug fixes especially the 6dB down with calibration mic, since Jerry said that if an SPL meter is used with the calibration of the mic this 6dB down would not have an effect. So should I update to this current version, is this the version all are using? Also can you give me a link (I'm not there yet) with the adapter needed to take the pre-out measurements after connecting a RCA cable to the pre-out I want to measure, I know I'm way ahead of myself but want to have everything I need. TIA
Cheers Jeff
 
#12,034 ·
Personally, I would be concerned with the 15-20dB rise as the curve approaches 20Hz. If this is an intentional house curve, then that is fine. Otherwise, I would be working to flatten it out. Perhaps you can post a waterfall graph to see how the rising low frequency response affects bass ringing. Also, an ETC graph would allow us to see how well you have controlled room reflections.
How should I set the graph limits for the ETC graph?
 
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