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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).
 
#261 ·

Quote:
Originally Posted by kbarnes701  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/240#post_22819110


You absolutely need measuring gear to optimise the XO region, otherwise any changes you make to the sub delays are just guesses. OmniMic works very well for this and is how I resolved my issues with the splice.


I wouldn't worry too much about the 'teething issues' we are reporting. For example, it took me 5 hours yesterday to get it all figured out (with much frustration, swearing, cursing of Bill Gates (and his dog) and hair-tearing. But... I did finally get there, or at least 95% of the way there. By the time the mics arrive, we should have a pretty good handle on how to get up and running quickly. Jerry is also working on a step-by-step (literally) guide that looks absolutely marvellous so far and will be a massive help to everyone once he is ready to publish it (soon). As everyone's laptop will be different, the guide cannot be perfect but I have used the first draft to set myself up and I can tell you it is a huge help. Where there are differences they are usually fairly obvious to work out - eg your soundcard will have a different name to my soundcard, but it is still obviously a soundcard. Jerry will also update the Guide as feedback comes in, so it will get better over time. It is a great piece of wrk IMO.

Keith - thanks for the reassurance - I look forward to AJ's guide and will screw my courage to the sticking post and muddle on!
 
#262 ·

Quote:
Originally Posted by mogorf  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/240#post_22819140


Thank you Max for clearing up matters. Will also be very useful when setting up a guide on "how to post graphs".


Appreciate your help as always.


Take care.

I think we should utilize some of the HTS forums FAQ's if that is possible? They have lots of information on how to take graphs and how to post them. I am not a forum guru, but is that a no no to repurpose others stuff? If so, I totally understand, but just don't want to reinvent the graph wheel here when it is tried and true over there. Just a thought.
 
#263 ·

Quote:
Originally Posted by cdnbum88  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/240#post_22819299

Quote:
Originally Posted by mogorf  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/240#post_22819140


Thank you Max for clearing up matters. Will also be very useful when setting up a guide on "how to post graphs".


Appreciate your help as always.


Take care.

I think we should utilize some of the HTS forums FAQ's if that is possible? They have lots of information on how to take graphs and how to post them. I am not a forum guru, but is that a no no to repurpose others stuff? If so, I totally understand, but just don't want to reinvent the graph wheel here when it is tried and true over there. Just a thought.
 

Linking to the HTS FAQs would be OK, but it does then take people from this site.  The FAQ I have in mind for this thread is a) for beginners, b) for the REW 5 USB Mic/HDMI connection method. 

 

I haven't thought this through yet, but my idea was to concentrate on a FAQ that had the basics - a lof it is actually covered in Jerry's Guide anyway. As you say, there's no point reinventing the wheel and if the HTS info is good for the purposes of this thread, then we should refer to their material. I think we have already agreed to use the HTS formats for graphs posted - anyone got a link to that BTW?
 
#264 ·

Quote:
Originally Posted by JChin  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/240#post_22817571

Quote:
Originally Posted by AustinJerry  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/240#post_22817502


That doesn't make any sense to me.  If you go into the sound option in control panel and select recording devices, even though the internal ATAPI mic and the mic connected to the external stereo mini-jack are listed, one of the two will be set as the default device.  The other device should be inactive.

Thats what I though as well unitl I tap on the laptop mic and Audyssey mic. Both picked up sound with mic 1 selected in REW input. This are pics saved from yesterday.


Before starting REW




Audyssey mic plugged in
 

I cannot get my laptop to recognise the Audyssey mic.

 

While I was there checking just now though I did notice you can disable the built-in mic by right clicking with it highlighted.  That solves the problem of both running at the same time.
 
#265 ·

Quote:
Originally Posted by djbluemax1  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/240#post_22818946


Nope, that's incorrect.

I don't object anything you said after, but what I've said is also correct. The average is more smooth than the individual measurements as you eliminate pretty random processes from the measurements (like comb-filtering is a little bit different on every other point and you get less of it when averaging and getting smoother picture). And.. I've tried it myself!
 
#266 ·

Pictures are always better than words.  Look at these graphs:

 



 



 

The top graph shows 8 measurements (actually my 8 Audyssey mic locations), with 1/12 smoothing.  The averaged response (the red curve) is therefore also at 1/12 smoothing (the curve has a -20dB offset so it is more visible for this example).

 

The bottom graph shows the same 8 measurements, but this time smoothed to 1/3, with a new average, also at 1/3 smoothing.

 

There are two points to this example.  First, @Igor, there is a semantic difference here.  The Average is not "smoother" in the sense that it has the same smoothing applied.  However, agreeing with your point, it "looks" smoother, because averages by definition smooth out the variations.

 

Second point is augmenting Max's excellent earlier post.  Even though an average represents the same smoothing as the underlying measurements being averaged, you can delete the average, apply a different smoothing to the underlying measurements, and re-generate the average based on the new smoothing.

 

REW is really flexibile in the way data can be represented!
 
#267 ·

Quote:
Originally Posted by asarose247  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/240#post_22817615


hello, this thread rocks and lets us roll on iwth REW.

Question i run 64 bit W7. ASIO will not properly install from either the website of from CNET. And the update link, 2.11. at ASIO also fails. I selected "use the proper setting" but i have no program in my file. I have the manual and and UNINSTALL BUT no program to run.

I dont have the mike as suggested yet (on order) but i'm trying to be prepared.

After ASIO installs, there will NOT be a program to run - ASIO support has been installed - when you run REW, you can then access the ASIO control panel from within Preferences (its not a stand alone program).

Hope this helps, Mike.
 
#268 ·
Kbarnes and AV mike

thank you for leg up. Its installed and I'm trying not to be. as was suggested, I'm "experimenting " with my audyssey mike.
 
#269 ·

Quote:
Originally Posted by kbarnes701  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/240#post_22819336


 

Linking to the HTS FAQs would be OK, but it does then take people from this site.  The FAQ I have in mind for this thread is a) for beginners, b) for the REW 5 USB Mic/HDMI connection method. 

 

I haven't thought this through yet, but my idea was to concentrate on a FAQ that had the basics - a lof it is actually covered in Jerry's Guide anyway. As you say, there's no point reinventing the wheel and if the HTS info is good for the purposes of this thread, then we should refer to their material. I think we have already agreed to use the HTS formats for graphs posted - anyone got a link to that BTW?
This is what I was hoping for, instead of 8 pages of setup problems which, I think, would have been better suited for the Home Theater Shack site.

The recommended settings for graphs is here:

http://www.hometheatershack.com/forums/rew-forum/934-please-read-posting-graph.html#axzz2HmZTEzXy

I've dusted off my old setup (RS SPL, Mobile Pre, old laptop, etc.) and look forward to working with the waterfalls that, hopefully, we'll all be generating and learning about.

Soon? 


Michael
 
#270 ·

Quote:
Originally Posted by LastButNotLeast  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/240#post_22821718

Quote:
Originally Posted by kbarnes701  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/240#post_22819336


 

Linking to the HTS FAQs would be OK, but it does then take people from this site.  The FAQ I have in mind for this thread is a) for beginners, b) for the REW 5 USB Mic/HDMI connection method. 

 

I haven't thought this through yet, but my idea was to concentrate on a FAQ that had the basics - a lof it is actually covered in Jerry's Guide anyway. As you say, there's no point reinventing the wheel and if the HTS info is good for the purposes of this thread, then we should refer to their material. I think we have already agreed to use the HTS formats for graphs posted - anyone got a link to that BTW?
This is what I was hoping for, instead of 8 pages of setup problems which, I think, would have been better suited for the Home Theater Shack site.

The recommended settings for graphs is here:

http://www.hometheatershack.com/forums/rew-forum/934-please-read-posting-graph.html#axzz2HmZTEzXy

I've dusted off my old setup (RS SPL, Mobile Pre, old laptop, etc.) and look forward to working with the waterfalls that, hopefully, we'll all be generating and learning about.

Soon? 


Michael
 

Thanks for the link. Yes, the 8 pages of setup problems can seem to be offputting I agree - just consider it as 'chatter' between the pioneers of this thread - Jerry will be publishing his Guide soon and I think that will be exactly what you are looking for. He has boiled it down to a series of 'steps' - follwing them leads you to taking your first measurements, along with a brief explanation of how to read and interpret them. From that point on, the discussion will be about how to use the info REW provides, mostly. It is a great Guide and I am sure you will enjoy it.
 
#271 ·

The 'standard' for graphs to be posted to the thread over at HTS is:

 

The preferred axis for ALL subwoofer graphs is:

VERTICAL = 45dB-105dB

HORIZONTAL = 15Hz-200Hz.



The preferred axis for full range graphs is:

VERTICAL = 45dB-105dB

HORIZONTAL = 15Hz-25,000Hz.


These values are defaulted into REW, but can easily change and must be set back to these axis for posting graphs.

 

Smoothing:

Smoothing should not be applied to subwoofer graphs. For full range graphs, 1/3 or 1/6-octave smoothing is beneficial.

The HTS graph standard is as below - you will see that they require logarithmic graphs, not linear:

 



 

 



 

 

Set the graph type by clicking the Freq Axis button.

 

 



 

 

With thanks to HTS for the information in this post.
 
#272 ·

Quote:
Originally Posted by kbarnes701  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/270#post_22822730


The preferred axis for ALL subwoofer graphs is:

VERTICAL = 45dB-105dB

HORIZONTAL = 15Hz-200Hz.




 
 

Wow, Keith, this seems to be an unfair standard.  What about those of us who have multiple subwoofers of and unnamed brand that have flat response all the way down to 10Hz?  I don't want to mention any names here, but aren't we depriving those participants the opportunity of their bragging rights?     
 
#273 ·

Quote:
Originally Posted by AustinJerry  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/270#post_22822905


Wow, Keith, this seems to be an unfair standard.  What about those of us who have multiple subwoofers of and unnamed brand that have flat response all the way down to 10Hz?  I don't want to mention any names here, but aren't we depriving those participants the opportunity of their bragging rights?     

Oooops Jerry, I think we are running into some trouble zone here. The UMIK-1 usb mic is spec'd down to 15 Hz, only!! And what about folks with subs in the 1 digit ULF (ultra low frequency) range? What mic do they use for their test?
 
#274 ·
I don't think 1/3rd smoothing is adequate for the upper frequencies. A narrow band large amplitude peak at, say, 5k would be audible but would not show up on the charts. There is a particular very expensive high end speaker that has such a peak at 10k that is quite audible. I would like to suggest nothing less than 1/6th smoothing.
 
#275 · (Edited)

Getting Started with REW: A Step-by-Step Guide


The purpose of this document is to provide a step-by-step guide for novice users of Room Equalization Wizard, freeware audio measurement software authored by John Mulkahy. This guide focuses on the recent enhancements to REW that support the use of USB microphones. You are encouraged to visit the REW forum, and to thoroughly read the REW Online Help documents.

Link to PDF:

Getting Started with REW
 
#276 ·

Quote:
Originally Posted by AustinJerry  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/270#post_22822905

Quote:
Originally Posted by kbarnes701  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/270#post_22822730


The preferred axis for ALL subwoofer graphs is:

VERTICAL = 45dB-105dB

HORIZONTAL = 15Hz-200Hz.




 
 

Wow, Keith, this seems to be an unfair standard.  What about those of us who have multiple subwoofers of and unnamed brand that have flat response all the way down to 10Hz?  I don't want to mention any names here, but aren't we depriving those participants the opportunity of their bragging rights?     
 

LOL. I did think that as I posted it... but you know, those of us with subs flat to 10Hz, or even lower, don't like to rub it in. Well, not too much.... ;)
 
#277 ·

Quote:
Originally Posted by mogorf  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/270#post_22822938

Quote:
Originally Posted by AustinJerry  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/270#post_22822905


Wow, Keith, this seems to be an unfair standard.  What about those of us who have multiple subwoofers of and unnamed brand that have flat response all the way down to 10Hz?  I don't want to mention any names here, but aren't we depriving those participants the opportunity of their bragging rights?     

Oooops Jerry, I think we are running into some trouble zone here. The UMIK-1 usb mic is spec'd down to 15 Hz, only!! And what about folks with subs in the 1 digit ULF (ultra low frequency) range? What mic do they use for their test?
 

I’d have preferred to see the range specced from 7Hz - 200Hz personally, because now I will have to make that graph for myself and then make another for posting here. Fortunately, REW is a huge step up from OM in that regard and at least I will only have to measure once. ;)
 
#278 ·

Quote:
Originally Posted by audioguy  /t/1449924/simplified-rew-setup-and...and-how-to-interpret-graphs/270#post_22822961


I don't think 1/3rd smoothing is adequate for the upper frequencies. A narrow band large amplitude peak at, say, 5k would be audible but would not show up on the charts. There is a particular very expensive high end speaker that has such a peak at 10k that is quite audible. I would like to suggest nothing less than 1/6th smoothing.
I agree with you - we could change the standard for this thread to 1/6th smoothing for full range graphs - HST allow either, so we would still be compatible.
 
#279 ·

I can thoroughly recommend that everyone downloads Jerry's step-by-step Guide. Without it (and Feri's help) I would not have got to the measuring stage. It is a terrific piece of work and I thank Jerry sincerely for the time and effort he has put in to this.
 
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