Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs - Page 4 - AVS Forum
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post #91 of 10741 Old 01-08-2013, 07:12 AM
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Originally Posted by AustinJerry View Post

Quote:
Originally Posted by kbarnes701 View Post

I had to go into Windows Control Panel and select Sounds and then select the 5509 Display Audio Sound option and then select Configure. In there it gave me some check boxes one of which was for 7.1. I ticked that box and all 8 channels appear in REW. I don't have surround backs either (I dio have Heights but they are not relevant here) so it's a bit academic, but at least all 8 are showing. 

Keith, until now, I had considered myself reasonably knowledgeable WRT Windows and PC configurations. However, I cannot find anywhere in my Control Panel where it references my AVR as a configurable audio device. Would it be possible for you to post several screen shots of where in the Control Panel you found these settings?

Thanks!

Edit: This is what I see

 

700

 

700

 

:

 

Jerry - I have to go back to the stable in a minute (there was a problem with the right rear nearside hoof which has now been fixed apparently, but just quickly, it is in that dialog box you show above that my 5509 appears an audio option called, IIRC, 5509 Display Audio - it appears below the built-in audio. I selected it and set it as default. If yours is not showing up there, then it seems that your Denon has not been recognised, which will explain the problem. I was careful to make all connections (well, the single HDMI connection) before booting the laptop and before running REW. I don't know if this matters but it is my standard practice.

 

I will be more than happy to make a screen cap for you, if you first tell me how to do it on Windows!  On the Mac you just press Apple-Shift-4 but I have no idea what you do on Windows (but I bet it ain't as easy! LOL). 

 

Back later, with equine consent.

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post #92 of 10741 Old 01-08-2013, 07:20 AM
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Originally Posted by jevansoh View Post


I'm actually really NOT liking the AVS editor, as I had a beautiful draft of what I just posted in post #2 which took literally hours/all night to create in MS Word and when I pasted it in, none of the formatting took and it was all garbled, so I just spent the last 30 minutes or so getting it "good enough" because I'm so tired and have to go to work now, too... I hate to ask, but you did (and are doing) such a great job with all the Audyssey docs, could you possibly copy all the text and try to fix it up a bit? I also basically just typed everything from memory and as I had each thought while answering Jerry's questions, which is what I used as the template to get started, and don't have the time or energy to go back and edit, proof read, cut down for size/redundancy, etc. You (especially with your background) are obviously a pro at that, and I sure would appreciate any help you can offer... Maybe PM it to me if/when you can fix 'er up, and I'll repost to make it more clear.

Thanks SO MUCH and if you aren't interested or don't have time I understand, but it never hurts to ask, right? wink.gif

--J

 

Welcome to the world of long AVS posts! :)

 

I am more than happy to work on the formatting for you, but I cannot, of course, edit your post, so I will have to post it here - you can then copy my post (using the Quote post button first to get it into the editor, and then repost as an edit to your original post).  I can then delete my post when you have finished with it. Posting it as a PM is likely to change the formatting IME. You can’t create anything in Word and have it reliably cross over to the AVS editor platform. I use a text editor and then format it all in the AVS editor.

 

I wouldn’t worry to much about the formatting at this stage - when I make the 'official' FAQ, I will take care of it all. I am reluctant to start the FAQ yet because I need a better idea of how to structure it, but I may start it in the Post Testing forum so you can have a look at it and make comments. I will post a link. The reason I am reluctant to start it yet is because making major changes to it later is such a PITA thanks to the editor - so the better idea I have of how to structure it the easier it makes my life.

 

I have to go and attend to the bloody horse now, so it will be a little while before I get around to it.

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post #93 of 10741 Old 01-08-2013, 07:21 AM
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Originally Posted by mogorf View Post

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Originally Posted by kbarnes701 View Post

One more question - you said somewhere to set the REW prefs to 48kHz sampling rate (which I have done) - but why?

In case the sound card was set to 44.1kHz and REW to 48 kHz it could lead to false measurements. But now with ASIO4ALL this may have become obsolete, coz in the Asio Control Panel putting the check mark to "Always resample 44.1 kHz <-> 48 kHz" takes this load off our shoulders. smile.gif

 

Thanks Feri.

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post #94 of 10741 Old 01-08-2013, 07:23 AM
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Originally Posted by AustinJerry View Post

Actually, we are up to beta 12 now.  Thankfully, the new beta releases are quick to download and install.

 

Has it solved your problem?

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post #95 of 10741 Old 01-08-2013, 07:30 AM
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Quote:
Originally Posted by kbarnes701 View Post

Jerry - I have to go back to the stable in a minute (there was a problem with the right rear nearside hoof which has now been fixed apparently, but just quickly, it is in that dialog box you show above that my 5509 appears an audio option called, IIRC, 5509 Display Audio - it appears below the built-in audio. I selected it and set it as default. If yours is not showing up there, then it seems that your Denon has not been recognised, which will explain the problem. I was careful to make all connections (well, the single HDMI connection) before booting the laptop and before running REW. I don't know if this matters but it is my standard practice.

I will be more than happy to make a screen cap for you, if you first tell me how to do it on Windows!  On the Mac you just press Apple-Shift-4 but I have no idea what you do on Windows (but I bet it ain't as easy! LOL). 

Back later, with equine consent.

Since screen captures will become increasingly important, here is the procedure:

- In the Start menu, click on All Programs, then Accessories, and then open the Snipping Tool.
- with Snipping Tool open, click the left mouse button and drag the box so that it holds what you want to capture
- Release the mouse button, and then click File, Save to store the screenshot as a JPG image.
- There are a couple of basic tools (a pen, highlighter and eraser) that you can use to augment the screen capture.
- Click New to capture new images

Back on topic, no need to send the screen shots now. I don't see my AVR in the list, so perhaps you are correct--my laptop has not recognized the AVR at this point. I'll continue chipping away at it.
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post #96 of 10741 Old 01-08-2013, 07:30 AM
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Originally Posted by kbarnes701 View Post

Has it solved your problem?

No difference.
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post #97 of 10741 Old 01-08-2013, 08:22 AM
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A quick thanks to those of you taking the time to create this thread and also recognizing that beginners (in sound measurements) like myself are following along in the hopes of understanding how our rooms react to sound and being able to improve overall sound quality.
Quote:
Originally Posted by AustinJerry View Post

Since screen captures will become increasingly important, here is the procedure:
- In the Start menu, click on All Programs, then Accessories, and then open the Snipping Tool.
- with Snipping Tool open, click the left mouse button and drag the box so that it holds what you want to capture
- Release the mouse button, and then click File, Save to store the screenshot as a JPG image.
- There are a couple of basic tools (a pen, highlighter and eraser) that you can use to augment the screen capture.
- Click New to capture new images

A quick note about attaching images. I've found unless you're using the full site version on a PC, there isn't an option to attach pics but rather just embed them via an http link. If someone knows a way around this I would appreciate it as I often use my iPad/iPhone for browsing the site but usually relegate posts involving attachments to my PC.

p.s.
LOVE the snipping tool and take note that you can set it to capture the active window (see below) exactly as it is sized so no dragging necessary.

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post #98 of 10741 Old 01-08-2013, 09:21 AM
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Before you order the USB mic or spend any money at al, my suggestion is to use the measurement mic that came with your AVR. Assuming your laptop has a mic input, simply plug it into there and start to play around. The reason is to make sure you can make sense of the process. This is NOT a tool that is easily mastered or understood. There is a learning curve and you need to dedicate significant amount of time to learning how to use the tool and figuring out what the results mean. I suspect most people will not be up for the challenge.

The AVR mic will not be accurate in the absolute but as a relative instrument, will be plenty to get you through learning what this whole affair is about. If what you see out of there makes no sense, then the results from a fancy mic will not make sense either. Heck, start with your laptop mic if it has one built into it! Again, all you are trying to do is see if you can get the program to produce any kind of measurement for you.

Likewise, for output simply use the headphone jack. Don't mess with HDMI and ASIO for now. If you want to get fancy, hook that up to the mic input and run through the calibration. This will flatten the mic/output of the laptop.

Become very familiar with your operating system sound control panel. There are a number of critical things in there such as resampling (which Windows does by default to 48 Khz), Mic level, mono vs stereo, effects (which hopefully are all off), the number of channels exposed by HDMI, whether HDMI is even connected and recognized, etc. My team at Microsoft wrote the whole audio pipeline in Windows but even I get caught once in a while with some setting in there redface.gif.

For now, don't worry about absolute values (ie. what SPL you are at). All you should care about is whether the relative values (i.e. one frequency vs another) make sense. Your goal is to generate a "sweep" (frequency response measurement) without getting errors, and having the output make sense. You have plenty of work here to do from setting the mic and AVR levels right to making sure one speaker spits out sound (disconnect speaker wires if you have to, to get one sound but keep levels low as to not cause the amp to go into protection).

Step after that, and this is critical, is to understand what filtering means and how to use it. I cover that partially for the frequencies above "transition" (bass) in my article: http://www.madronadigital.com/Library/RoomReflections.html. I suggest, as i show there, to run different sweeps for bass and above bass as they require different filtering. If you have run auto eq in your AVR, turn it on and off and see what effect they generate here. Switch from one speaker to the other and see what happens (compare left to right and to center). All of this has to "make sense" or you are still not there.

And oh, stay with the non-beta version of REW for all of this.

To be sure, once you master the tool, there is "fun" to be had and good learning. But unless you get lucky and have lots of knowledge, it is not likely to get started that way. This work is also very tedious and so many things can cause you to get nothing at all; hence the frustrations cited by some.

Walk before you run smile.gif. HDMI audio can be hugely difficult to get right. You need to make sure everything else is under control and this being your only variable.

Amir
Founder, Madrona Digital
"Insist on Quality Engineering"

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post #99 of 10741 Old 01-08-2013, 09:27 AM
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Quote:
Originally Posted by AustinJerry View Post

Quote:
Originally Posted by kbarnes701 View Post

Jerry - I have to go back to the stable in a minute (there was a problem with the right rear nearside hoof which has now been fixed apparently, but just quickly, it is in that dialog box you show above that my 5509 appears an audio option called, IIRC, 5509 Display Audio - it appears below the built-in audio. I selected it and set it as default. If yours is not showing up there, then it seems that your Denon has not been recognised, which will explain the problem. I was careful to make all connections (well, the single HDMI connection) before booting the laptop and before running REW. I don't know if this matters but it is my standard practice.

I will be more than happy to make a screen cap for you, if you first tell me how to do it on Windows!  On the Mac you just press Apple-Shift-4 but I have no idea what you do on Windows (but I bet it ain't as easy! LOL). 

Back later, with equine consent.

Since screen captures will become increasingly important, here is the procedure:

- In the Start menu, click on All Programs, then Accessories, and then open the Snipping Tool.
- with Snipping Tool open, click the left mouse button and drag the box so that it holds what you want to capture
- Release the mouse button, and then click File, Save to store the screenshot as a JPG image.
- There are a couple of basic tools (a pen, highlighter and eraser) that you can use to augment the screen capture.
- Click New to capture new images

Back on topic, no need to send the screen shots now. I don't see my AVR in the list, so perhaps you are correct--my laptop has not recognized the AVR at this point. I'll continue chipping away at it.

 

OK - thanks for the info on the Snipping Tool. I have sorted out the horse now and will have another run through here later. If there is anything I missed, or anything else that springs to mind, I will of course let you know.

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post #100 of 10741 Old 01-08-2013, 09:31 AM
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Quote:
Originally Posted by jkasanic View Post

A quick thanks to those of you taking the time to create this thread and also recognizing that beginners (in sound measurements) like myself are following along in the hopes of understanding how our rooms react to sound and being able to improve overall sound quality.
Quote:
Originally Posted by AustinJerry View Post

Since screen captures will become increasingly important, here is the procedure:
- In the Start menu, click on All Programs, then Accessories, and then open the Snipping Tool.
- with Snipping Tool open, click the left mouse button and drag the box so that it holds what you want to capture
- Release the mouse button, and then click File, Save to store the screenshot as a JPG image.
- There are a couple of basic tools (a pen, highlighter and eraser) that you can use to augment the screen capture.
- Click New to capture new images

A quick note about attaching images. I've found unless you're using the full site version on a PC, there isn't an option to attach pics but rather just embed them via an http link. If someone knows a way around this I would appreciate it as I often use my iPad/iPhone for browsing the site but usually relegate posts involving attachments to my PC.

p.s.
LOVE the snipping tool and take note that you can set it to capture the active window (see below) exactly as it is sized so no dragging necessary.

 

It is generally better to embed the images - people are less likely to look at an attachment, whereas they can’t miss an embedded image. You don't need to use a url - use the tool in the AVS editor to upload the image directly into your post...

 

I have circled it in red in the screen cap below:

 

 

1000

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post #101 of 10741 Old 01-08-2013, 09:40 AM
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Quote:
Originally Posted by amirm View Post
 
Likewise, for output simply use the headphone jack. Don't mess with HDMI and ASIO for now. If you want to get fancy, hook that up to the mic input and run through the calibration. This will flatten the mic/output of the laptop.
 

I guess you missed the title of this thread?  It's "Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs".

 

Quote:
You have plenty of work here to do from setting the mic and AVR levels right to making sure one speaker spits out sound (disconnect speaker wires if you have to, to get one sound but keep levels low as to not cause the amp to go into protection).

 

Again, you don't seem to have bothered to actually check what the REW beta and HDMI connection do. There is no need to disconnect speaker wires when using HDMI - one simply selects the channel one wishes to test. If you can't be bothered to check the relevant version of the program you are discussing, then your 'advice' is likely to be pointless.

 

 

Quote:
And oh, stay with the non-beta version of REW for all of this.
 

And how does that fit in with using HDMI connection?  It is only possible in the beta. Again, I'd ask you to look at the title of a thread before you start posting in it.

 

The 'good' news - you're (temporarily) off my Block list.

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post #102 of 10741 Old 01-08-2013, 09:50 AM
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Quote:
Originally Posted by amirm View Post

Before you order the USB mic or spend any money at al, my suggestion is to use the measurement mic that came with your AVR. Assuming your laptop has a mic input, simply plug it into there and start to play around. The reason is to make sure you can make sense of the process. This is NOT a tool that is easily mastered or understood. There is a learning curve and you need to dedicate significant amount of time to learning how to use the tool and figuring out what the results mean. I suspect most people will not be up for the challenge.

The AVR mic will not be accurate in the absolute but as a relative instrument, will be plenty to get you through learning what this whole affair is about. If what you see out of there makes no sense, then the results from a fancy mic will not make sense either. Heck, start with your laptop mic if it has one built into it! Again, all you are trying to do is see if you can get the program to produce any kind of measurement for you.

Likewise, for output simply use the headphone jack. Don't mess with HDMI and ASIO for now. If you want to get fancy, hook that up to the mic input and run through the calibration. This will flatten the mic/output of the laptop.

Become very familiar with your operating system sound control panel. There are a number of critical things in there such as resampling (which Windows does by default to 48 Khz), Mic level, mono vs stereo, effects (which hopefully are all off), the number of channels exposed by HDMI, whether HDMI is even connected and recognized, etc. My team at Microsoft wrote the whole audio pipeline in Windows but even I get caught once in a while with some setting in there redface.gif.

For now, don't worry about absolute values (ie. what SPL you are at). All you should care about is whether the relative values (i.e. one frequency vs another) make sense. Your goal is to generate a "sweep" (frequency response measurement) without getting errors, and having the output make sense. You have plenty of work here to do from setting the mic and AVR levels right to making sure one speaker spits out sound (disconnect speaker wires if you have to, to get one sound but keep levels low as to not cause the amp to go into protection).

Step after that, and this is critical, is to understand what filtering means and how to use it. I cover that partially for the frequencies above "transition" (bass) in my article: http://www.madronadigital.com/Library/RoomReflections.html. I suggest, as i show there, to run different sweeps for bass and above bass as they require different filtering. If you have run auto eq in your AVR, turn it on and off and see what effect they generate here. Switch from one speaker to the other and see what happens (compare left to right and to center). All of this has to "make sense" or you are still not there.

And oh, stay with the non-beta version of REW for all of this.

To be sure, once you master the tool, there is "fun" to be had and good learning. But unless you get lucky and have lots of knowledge, it is not likely to get started that way. This work is also very tedious and so many things can cause you to get nothing at all; hence the frustrations cited by some.

Walk before you run smile.gif. HDMI audio can be hugely difficult to get right. You need to make sure everything else is under control and this being your only variable.

Amir - Plugging your article on a commercial website is against the spirit of this thread, and post#1 asks not to plug your own wares, so why are you doing so?
To get more hits on your site?

Other acoustic threads you enter into degrade shortly......

These guys want to use simple plug-n-play, don't you read what was posted here before penning your own post?
Quote:
Originally Posted by jevansoh View Post

PLEASE only post in this thread on topic and understand that derailments from trolls, folks trying to sell their wares (constantly plugging certain acoustical products) and bickering/arguing will NOT be tolerated.

--Jason
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post #103 of 10741 Old 01-08-2013, 10:09 AM
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Originally Posted by kbarnes701 View Post

I guess you missed the title of this thread?  It's "Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs".
I was going by what the OP said
Quote:
Originally Posted by jevansoh View Post

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 was under the impression that the thread as OP said, was about the tool usage and not just how to get HDMI and USB working. My apologies for misunderstanding. Given the sentiments expressed, I will exist the thread.

Amir
Founder, Madrona Digital
"Insist on Quality Engineering"

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post #104 of 10741 Old 01-08-2013, 10:33 AM
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I don't think Amir's post was at all inappropriate - nor self serving. REW is not plug and play but, by using the new USB mic and and HDMI cable, was "advertised" as such on AVS. And based upon my experiences (with the original REW and this new beta) I concur that the walk before running approach is quite valid.

Amir is very knowledgeable in many areas of audio and I think it unfortunate that we chased him away.
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post #105 of 10741 Old 01-08-2013, 10:35 AM
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Quote:
Originally Posted by kbarnes701 View Post

 

It is generally better to embed the images - people are less likely to look at an attachment, whereas they can’t miss an embedded image. You don't need to use a url - use the tool in the AVS editor to upload the image directly into your post...

 

I have circled it in red in the screen cap below:

 

 

1000

 

Thanks Keith.  What I meant was that with an iPad or iPhone, the "embed" image option you have referenced only gives you the option to enter a URL address (at least using Safari with the full version of the site).  See below screen cap from my iPad.  Of course, I typically use the embed option rather than "attachment" option but I meant in the context of "attaching" an image file using the embed image option rather than having to enter a URL address.  Hope that clears it up.  I suppose another browser might allow me to enable this option on the iPad but I'm guessing the overall lack of a file browser (without another app installed) is the root cause of the issue.  On the plus side, I did find that my editor was set to BB instead of Rich Text based on your screen cap above, so at least now I can see previews of my screen caps!  Sorry everyone for all the OT chatter!

 

700

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post #106 of 10741 Old 01-08-2013, 10:59 AM
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Quote:
Originally Posted by audioguy View Post

I don't think Amir's post was at all inappropriate - nor self serving. REW is not plug and play but, by using the new USB mic and and HDMI cable, was "advertised" as such on AVS. And based upon my experiences (with the original REW and this new beta) I concur that the walk before running approach is quite valid.
 

 

 

Yes that is true. You've ignored the rest of his post and taken that line out of context (have you caught Amiritis? :)).

 

Was there anything in my response to his post that was not correct or that you wish to comment on?

 

Amirm is the master of taking things out of context, of distorting what people have said, of cutting and pasting page after page of stuff that he doesn't actually fully understand, of personally discrediting those who call him out and who come between him and his agenda. This is the guy who told me in another thread that there is "no such thing as Reference" and that my FAQ remarks on the subject were thus invalid and when I pointed out to him what Reference is, in the context of the FAQ, he first denied he had said what he said, then he misquoted me, then he quoted the FAQ out of context and finally he made several attempts to discredit me.

 

I am sorry that this has come up but you only need to search on his name and check to see how many threads he derails with his meandering, usually irrelevant, frequently inaccurate posts. 

 

 

Quote:

Amir is very knowledgeable in many areas of audio and I think it unfortunate that we chased him away.

 

Well, to put that better, "Amir would like you to believe he is very knowledgeable in many areas of audio". The most knowledgeable area he is master of is promoting his store where he sells a range of audiofool products at inflated prices. This is the man whose knowledge doesn't extend to understanding the difference between a room for the recording of sound and a room for the reproduction of sound - someone who doesn’t know what the E in ET stands for but will post "authoritatively" on the subject for page after page.

 

Localhost's post here may have been "ungentlemanly" but it was also spot on for accuracy. 

 

Amirm has posted what, once or maybe twice here, and already the thread is being derailed. If he continues to post here, then the thread is doomed IMO, as have been so many others where he has "contributed". So, au contraire, unlike you I don't think it is 'unfortunate' if we have chased him away - it is a blessing.

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post #107 of 10741 Old 01-08-2013, 11:03 AM
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Originally Posted by mtbdudex View Post

 
Amir - Plugging your article on a commercial website is against the spirit of this thread, and post#1 asks not to plug your own wares, so why are you doing so?
To get more hits on your site?

Other acoustic threads you enter into degrade shortly......

These guys want to use simple plug-n-play, don't you read what was posted here before penning your own post?
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Originally Posted by jevansoh View Post

PLEASE only post in this thread on topic and understand that derailments from trolls, folks trying to sell their wares (constantly plugging certain acoustical products) and bickering/arguing will NOT be tolerated.

--Jason

 

He ONLY posts to further his agenda. He won’t have read the posts in this thread and he clearly didn’t even read the thread title - he barges in and starts, with his very first post, his campaign of self-promotion. I have always thought it is unfortunate that AVS doesn’t allow a thread starter to ban an individual from the thread he has started - it would ensure that many, many threads that have been derailed by Amirm would have prospered.

 

"Other acoustic threads you enter into degrade shortly......" - you can say that again! ALL of them IME.

 

EDIT: I am so fuming I have come back to add this: the cheek of someone to come into a thread which in its very title says that it is about REW and HDMI and then to tell people to "not mess about with HDMI" and to "not use the Beta of REW" is breathtaking.  He says he has gone - I hope he meant it, for the sake of Jason's thread.

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post #108 of 10741 Old 01-08-2013, 11:14 AM
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Quote:
Originally Posted by kbarnes701 View Post

He ONLY posts to further his agenda. He won’t have read the posts in this thread and he clearly didn’t even read the thread title - he barges in and starts, with his very first post, his campaign of self-promotion. I have always thought it is unfortunate that AVS doesn’t allow a thread starter to ban an individual from the thread he has started - it would ensure that many, many threads that have been derailed by Amirm would have prospered.

"Other acoustic threads you enter into degrade shortly......" - you can say that again! ALL of them IME.


EDIT: I am so fuming I have come back to add this: the cheek of someone to come into a thread which in its very title says that it is about REW and HDMI and then to tell people to "not mess about with HDMI" and to "not use the Beta of REW" is breathtaking.  He says he has gone - I hope he meant it, for the sake of Jason's thread.

+1 on that. I'm not overly familiar with his past but we've got our hands full trying to get the REW beta up to snuff with HDMI, and to even begin to understand what Jason's trying to accomplish with this thread. I may well throw my hands up and stick with OmniMic if this begins to looks like quantum physics (or a time investment best suited to retired hermits rather than overworked statisticians smile.gif), but at the very least, it's educational.

Stuart

 

Denon 4311 with XT32 and Audyssey Pro

Oppo 93 and 103

Panasonic VT50

Sherwood R-972 with its version of the Trinnov Optimizer

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PSB Imagine T2, Center, and Surrounds (as of 5/2014); HSU ULS-15 subs (2)

 

The Audyssey FAQ Guide can be found here:

http://www.avsforum.com/...

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post #109 of 10741 Old 01-08-2013, 11:21 AM
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Originally Posted by kbarnes701 View Post

I guess you missed the title of this thread?  It's "Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs".

Just to raise a question -- is there a reason we have specifically limited the scope of this thread to the HDMI connection only? Leaving poor my-laptop-only-has-a-headphone-jack chumps like me out in the cold?

I thought the original intention was to help users get up and running with the new (nearly) PNP options for USB mics, understand REW basics, and utilize this knowledge to help optimize their system in advance of running room correction. I'm fine with having most of the discussion centered on those who want to use the HDMI output option to test individual channels, but I don't see what it's necessary to limit the scope of this thread to only HDMI output. Aren't all the principles discussed valid even if I'm using an RCA cable to test my L, R, or C channels the "old fashioned" way?

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post #110 of 10741 Old 01-08-2013, 11:34 AM
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I am also starting getting deeper into REW, and welcome the creation of a thread like this one on AVS. smile.gif

Is this thread strictly reserved to USB mics and HDMI, or can different REW setups / measurements be shared?

This is what I have been using:

- Dell inspiron 1525 laptop (oldish)
- Art USB dual pre
http://www.parts-express.com/pe/showdetl.cfm?partnumber=245-8688
- EMM-6 microphone
http://www.parts-express.com/pe/showdetl.cfm?partnumber=390-801
- analog mini-jack to RCA output cable
- REW 5.0.1b12 with Java drivers
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post #111 of 10741 Old 01-08-2013, 11:44 AM
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Originally Posted by jkasanic View Post

 

Thanks Keith.  What I meant was that with an iPad or iPhone, the "embed" image option you have referenced only gives you the option to enter a URL address (at least using Safari with the full version of the site).  See below screen cap from my iPad.  Of course, I typically use the embed option rather than "attachment" option but I meant in the context of "attaching" an image file using the embed image option rather than having to enter a URL address.  Hope that clears it up.  I suppose another browser might allow me to enable this option on the iPad but I'm guessing the overall lack of a file browser (without another app installed) is the root cause of the issue.  On the plus side, I did find that my editor was set to BB instead of Rich Text based on your screen cap above, so at least now I can see previews of my screen caps!  Sorry everyone for all the OT chatter!

 

 

 

Ah right. I browse on my iPad but rarely reply to a post on it as I find it tedious in so many ways (mainly the virtual keyboard). I am enlightened by your post.

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post #112 of 10741 Old 01-08-2013, 11:49 AM
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Hi all, I download ASIO4ALL 2.10 and not 2.11 beta 1. Do I need 2.11 beta 1?
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post #113 of 10741 Old 01-08-2013, 11:52 AM
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Originally Posted by sdrucker View Post

+1 on that. I'm not overly familiar with his past but we've got our hands full trying to get the REW beta up to snuff with HDMI, and to even begin to understand what Jason's trying to accomplish with this thread. I may well throw my hands up and stick with OmniMic if this begins to looks like quantum physics (or a time investment best suited to retired hermits rather than overworked statisticians smile.gif), but at the very least, it's educational.

 

I don't think it is going to be as difficult as some think, Stuart. I managed to get it running, with help from this thread, in a few minutes. All the clues were in the thread - and remember I am not a Windows user. I think that once Jason has made a step-by-step Setup Guide everyone will be up and running in no time. If I had my mic, I would be doing measurements now!  Of course, I wouldn't necessarily know what to measure, nor how to interpret the graphs, nor what to do afterwards, but that is another issue :)

 

If anything, it may have been the use of Plug & Play that was unwise - it may have led some to take it literally (as is the case with OM). It's close to PnP but not quite there yet (with the CPL mic anyway). It's always better to underpromise and overdeliver than the other way around of course.

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post #114 of 10741 Old 01-08-2013, 11:55 AM
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Quote:
Originally Posted by batpig View Post

Quote:
Originally Posted by kbarnes701 View Post

I guess you missed the title of this thread?  It's "Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs".

Just to raise a question -- is there a reason we have specifically limited the scope of this thread to the HDMI connection only? Leaving poor my-laptop-only-has-a-headphone-jack chumps like me out in the cold?

 

Not sure, BP. Jason created the thread title - I don't think he meant to exclude RCA connections (and his first and second posts support that hypothesis). Maybe he couldn’t make the thread title any longer wink.gif

 

 

Quote:
I thought the original intention was to help users get up and running with the new (nearly) PNP options for USB mics, understand REW basics, and utilize this knowledge to help optimize their system in advance of running room correction. I'm fine with having most of the discussion centered on those who want to use the HDMI output option to test individual channels, but I don't see what it's necessary to limit the scope of this thread to only HDMI output. Aren't all the principles discussed valid even if I'm using an RCA cable to test my L, R, or C channels the "old fashioned" way?

 

I concur entirely, and without speaking for Jason in any way, who will correct me if I am wrong, I am sure that it is Jason's intent to do exactly what you say above.

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post #115 of 10741 Old 01-08-2013, 11:59 AM
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Quote:
Originally Posted by BarracudaDelGato View Post

I am also starting getting deeper into REW, and welcome the creation of a thread like this one on AVS. smile.gif

Is this thread strictly reserved to USB mics and HDMI, or can different REW setups / measurements be shared?

This is what I have been using:

- Dell inspiron 1525 laptop (oldish)
- Art USB dual pre
http://www.parts-express.com/pe/showdetl.cfm?partnumber=245-8688
- EMM-6 microphone
http://www.parts-express.com/pe/showdetl.cfm?partnumber=390-801
- analog mini-jack to RCA output cable
- REW 5.0.1b12 with Java drivers

 

Jason is the best person to answer that, but if it was my response to Amirm that has made you wary of joining in, please don't let it. I was simply pointing out to Amirm that it is not appropriate to come into a thread without reading any of it - certainly not the 'mission statement' in post 1 and certainly not even the thread title and then to start telling people to ignore HDMI, not to use the Beta and so on.

 

I am sure you will find the thread useful - if not for the HDMI setup stuff, at least for the 'how to measure, what to measure, how to read the graphs, what to do next' etc etc. The main thing about this thread is that most of us are REW virgins, so no question is a silly one, no level of expertise is assumed, and those who do have REW experience - notably Jason of course - but also Feri, Jerry and others - are more than willing to share.

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post #116 of 10741 Old 01-08-2013, 11:59 AM
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Quote:
Originally Posted by JChin View Post

Hi all, I download ASIO4ALL 2.10 and not 2.11 beta 1. Do I need 2.11 beta 1?

Why do you download a previous version when the latest one is on the same page? www.asio4all.com

No need to answer, just do it!! tongue.gif
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post #117 of 10741 Old 01-08-2013, 12:10 PM
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Originally Posted by mogorf View Post

 
One more thing I'd like to add here is the case when only the subwoofer channel is measured by pinging it via channel #4 (LFE). As we already know the Bass Management module (as per the LFE standard) in the AVR/AVP adds a +10 dB boost to the LFE signal (to make it clear, only to the LFE and not to the redirected bass from satellites). So, be careful with setting the test signal volume, coz in this case the test signal will be much louder that when sending it at the same input level to the satellites. Exactly +10 dB louder!!

 

Feri, can you elaborate for me please?  Where do I set the test signal volume? WIth the discussion in Post 2 about using 100dB for the test signals (I think my house might fall down with 100dB from my two Submersives - LOL) I am cautious about the test tone volume. Any help you can give would be appreciated.

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post #118 of 10741 Old 01-08-2013, 12:25 PM
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Originally Posted by jevansoh - this is the (slightly) better formatted version of Post 2. Jason - if you go into the editor and copy this, you should be able to edit it back into your own post.
--------------------------------------------------------------------------------------------------------------------
 
Thanks to AustinJerry and all the rest of you for asking a lot of great questions, which I've answered and added to below.
 
To get us started, below are some FAQ’s, do’s, do not’s, how’s, and why’s on a variety of subjects that both come up often and unfortunately, don’t come up often enough.
 
Q: Did I configure my graphs properly? Are the horizontal and vertical scales set properly? What are the various settings in the "Controls" panel for each type of graph?
 
A: You will use the “Controls” and “Limits” function located at the top right of your screen in REW most often. There are different settings for different graphs and different reasons for each one which is explained below.
 
  • Frequency Response – You need to set the top and bottom limits to fit the “unsmoothed” frequency response graph on your screen, but with as much resolution as possible. It is easy to make any graph look “good” and by not showing much resolution almost anything can be made to look flat. Pretty graphs are not what we’re after though. A good way to start is to look at the highest peak on the frequency response.

    Let’s say it’s 85db for example. Click “Limits” and set the “Top” limit to no more than 90db so the highest point in the graph will be close to the top of your screen but you have a bit of room to spare with nothing spilling over the top. Then for the bottom, set it to where the bottom of the longest spike, which will always be in the upper frequencies past about 2khz or so is shown and you’ve maxed out your resolution. Then verify that on the left hand side of your screen that the graph lines are in increments of 5db. Less than this is too much resolution and more isn’t enough.

    The standard is 5db and is what most people are used to looking at. If you see a lot of comb filtering and are measuring an untreated room and without EQ you may find it impossible to get within these parameters on the upper end of the frequency spectrum. As long as you show the highest peak and have about 60db showing below this, it’s okay if you can’t quite fit all the vertical lines/comb filtering on your screen, but make certain you don’t clip the top/peaks off. As for the left and right limits, these will differ depending on what you’re working on or sharing at the time. You can set the “Left” limit to 20hz for instance, and the “Right” limit to 20000hz for instance, to show the entire audible range of the frequency response, but more commonly you’ll either be measuring the effects of bass trapping and want to focus more on the lower frequencies or measuring the effects of different placement of acoustical panels, speaker placement, listener placement, etc, and be focusing more on mid and high frequencies. To show more resolution you can set the left and right limits to just show 10hz to 300hz for example to get the maximum resolution in your graphs for modal frequencies.

 

TIP: ALWAYS MEASURE FULL RANGE, IE: 10HZ – 20000HZ AS YOU CAN MANIPULATE THE GRAPHS LATER TO ONLY SHOW THE PORTION YOU WANT. NEVER LIMIT MEASUREMENTS TO ONLY 10HZ – 200HZ FOR EXAMPLE, AS IT ONLY TAKES A FEW MORE SECONDS TO DO A FULL MEASUREMENT SWEEP AND THAT DATA CAN BECOME INVALUABLE LATER.

 

  • Waterfall aka Cumulative Spectral Decay – This is a much more important graph than a simple frequency response and one we’ll surely be talking about it more detail. It’s also much more important we get this one right when sharing it with others as just like the frequency response, almost any waterfall graph can be made to look good, but we want the real scoop and not pretty graphs to sell acoustical treatments.

    This graph shows us frequency against time (there is a lot more to the explanation than this, but we’ll start here) and is used mainly to view lower frequencies, below 300hz or so. Recommended graph settings for left/right limits are 20hz – 300hz. If you have a subwoofer that goes lower than 20hz with substantial output, it is still not necessary to show frequencies below 20hz unless you have a very large room (longer than 30ft or more) that can modally support these lower frequencies. This graph is used to look at modal decay and can show ringing and why you may have one-note bass. It can also be used to show what your Room EQ software has done and if it’s made any of the ringing “worse” as sometimes happens. As for the “Top” and “Bottom” limits, you want to follow the same advice as above in the frequency response, showing 60db. You need to take all of your measurements with as little noise in the room as possible, but this measurement especially needs to show 60db above the noise floor, or as close to it as possible. For instance, the average American living room has an approximately 40db noise floor. That means your measurements need to be taken at about 100db which is very loud.

 

TIP: WEAR EAR PLUGS WHEN TAKING MEASUREMENTS. Taking measurements at this level will do a few things. First, and most importantly, it will get you above the noise floor so you can get accurate decay times and secondly it will show you how flat your subwoofer truly is down at 15-20hz when played at this volume. Lot’s of people brag they have “Flat” sub response down to 10hz, but at what level? 60db? 70db? You cannot hear or feel 10hz at 70db but at 100db if you have a sub-woofer(s) that can perform with reasonable distortion at this level, you have something to be quite proud of, along with a literally shaking foundation. If you cannot run a measurement at 100db and you cannot get your noise floor below 40db your measurements aren’t totally invalid, but you may not be able to get the full picture or capture your true in room decay times to 60db.

 

TIP: THE RT60 TAB/MEASUREMENT IS USELESS FOR SMALL ACOUSTICAL SPACES, WHICH IS EVERY “HOME” IN THE WORLD. THERE IS NO RT60 IN SMALL ROOMS, WHICH IS WHAT WE’RE DISCUSSING ON THIS THREAD. WE WILL NOT DISCUSS RT60 FURTHER AS IT IS MEANINGLESS, HOWEVER, DECAY TIMES IN MODAL FREQUENCIES ARE VERY IMPORTANT AND IS A BIG TOPIC ALONG WITH A HARD PROBLEM TO SOLVE.

 

  • In short, the goal for decay times for an average sized living room or dedicated home theater in the USA is somewhere in the range of 300ms to 500ms for frequencies between 500hz and 20khz and a good rule of thumb is not more than 450hz for modal frequencies. The ultimate goal is to make the entire spectrum not differ more than 10% full range, but that’s hard to do because unless you know the tricks of the trade (which we’ll talk about on this thread) you will find that as you add more bass trapping to get the decay times down for the lower frequencies, you overdeaden/overdampen the upper frequencies. There are several workarounds for this and we’ll go into much more detail in the thread on how to compensate for this.

 

  • ETC – Envelope/Energy Time Curve – The settings for this graph aren’t as precise, but for what we’ll mostly be looking at, I recommend showing from 0 – 40ms unless your room is longer than 30’ or so and again, show at least 60db on the left side. What we want to see here depends on the acoustical model you’ve chosen. However, a good rule of thumb, to begin with at least, is to have no spikes above -20db between 0ms and 20ms. Anything under 20db is fine. There are several nuances to this though. All the spikes should decay as evenly as possible and be spaced as evenly as possible. Having no spikes above -20db (from reference set as 0db) is effectively anechoic, or “without echo” and this is a good thing, to a point. However, this initial time delay (sometimes referred to as ITG or initial time gap) needs to be terminated at some point or you’ll have a rather dull, dead, and lifeless sounding room. A good termination point is somewhere past 15ms and no more than about 25ms. This should be as close to or above -12db as possible to terminate this initial time delay gap. This is critical in a LEDE/RFZ room and we’ll go into much more detail in the thread on the how-to. The ETC is often very misunderstood and overlooked, and this is very unfortunate as it is the most critical of all tools and by it being time based you can easily use it to calculate and solve for most other problems, so this is my personal pick for a desert island graph where if I could only pick one…
 
Q: How should the speakers be configured before taking these measurements? Do I measure one speaker at a time for ETC? Does the waterfall need all subs as well as the main speakers in the measurement? Is Audyssey on or off? Do I take measurements only at the MLP, or at several spots in the room?
 
A: There are different configurations for different types of measurements. You should always measure the full spectrum starting with the lowest frequency your subwoofer(s) will play to and going up to 20000hz no matter what you will be analyzing. Using graph limiting, explained above, you can look at whatever range you wish, but it’s good to have all the data available.
 
  • Frequency Response – Measure L+Sub then measure R+Sub and overlay the two. NEVER measure together for this. It will show a lot of comb filtering and not give you true results. TIP: Comb Filtering doesn’t actually exist!! It’s simply the name we give to the visual effect we see on graphs! When you overlay the L+Sub and R+Sub graphs they should not deviate by more than +/- 2db from each other. If they do, you need to alter the speaker placement and/or listening position until there is as little deviation between the L and R speakers as possible.

 

TIP: DO NOT RELY ON ROOM CORRECTION SOFTWARE FOR THIS AND ALWAYS MEASURE WITHOUT ROOM CORRECTION ENGAGED!

 

  • Waterfall – This is the only measurement where you do actually want to measure both the Left and Right speakers along with all subwoofers, together. You’re looking at the combined response in the modal region on this graph, so you need every speaker playing that will be playing frequencies below 300hz at the same time, which is the Left, Right, and Subs.

 

  • ETC – See Frequency Response – Same thing applies – Overlay Left and Right and if spikes (equal to reflections) exist in one speaker but not the other, at the same point in time before 20ms or so (early reflections) then you don’t have symmetry and at the very least need to reflect, diffuse, or absorb the “different” spikes/reflections.

 

  • You will want to take two sets of measurements each time you make a change. The great thing about REW is you can look at many different graphs, set them up to view different parameters at a time, IE: Full range or limited range (as long as you always ‘measure’ full range to begin with) and manipulate the graphs to suit your needs any time in the future. Each time you measure, you should ALWAYS first measure with NO EQ then, without moving the mic, measure WITH EQ.

    Then you should move the mic a few inches to the left, and repeat, then to the right, repeat, up, down, etc. You can then look in the bottom left hand corner of your screen and click the “Average” button which will spatially average all of your measurements together. So you always want to take several measurements around your MLP and both with and without EQ for comparison and to see exactly what that EQ is really up to.
 
TIP: ALWAYS NOTATE YOUR MEASUREMENT BEFORE PROCEEDING TO THE NEXT MEASUREMENT. TRUST ME, YOU WILL “NOT” REMEMBER THE DETAILS LATER AND WITHOUT PROPER NOTES ON EACH MEASUREMENT, THE IMPORTANT MEASUREMENT CAN BECOME MEANINGLESS QUICKLY.
 
TIP: IF YOU WANT MORE RESOLUTION/DATA ON YOUR SCREEN, AT THE TOP OF THE MEASUREMENT NOTES ON THE LEFT HAND SIDE OF YOUR SCREEN, CLICK “COLLAPSE” AND THE AREA DESCRIBING EACH MEASUREMENT WILL SHRINK WHILE THE ACTUAL GRAPH WILL EXPAND. IF YOU WANT TO READ YOUR NOTES MORE CLEARLY LATER, SIMPLY CLICK THE SAME BUTTON AGAIN, WHICH WILL NOW READ, “EXPAND.”
 
Q: What do the waterfall graphs show? Does the Waterfall show any resonances that need to be looked at, or does the graph show something that is "good enough"?
 
A: Teaching you to understand how to interpret all the graphs in REW is one of the main goals of this thread.
 
In essence, the waterfall graph, if configured properly as detailed above, will show you certain frequencies that take longer to decay than others. If, for instance, 40hz “rings” out to 700ms but most of the rest of the frequencies stop ringing (this looks like mountains coming forward/towards you on your monitor) at 300ms, then you have a modal problem at 40hz and need to treat it with passive EQ, IE: Bass traps.
 
TIP: IF YOU CANNOT SEE YOUR MOUNTAINS FULLY DECAY ON YOUR MONITOR AND INSTEAD, YOU ONLY SEE “FLAT” PEAKS THEN YOU HAVEN’T SET THE “CONTROLS” TAB PROPERLY, LOCATED NEXT TO LIMITS. YOU WANT TO SET YOUR CONTROL TABS “TIME RANGE (MS) TO WHATEVER LEVEL IS NECESSARY TO SEE THE LONGEST MOUNTAIN PEAK FULLY DECAY INTO THE FLOOR. DEPENDING ON HOW STRONG THE PEAK IS AND WHETHER OR NOT YOUR ROOM IS TREATED, THIS COULD EASILY EXCEED 700-800MS. AS YOU ADD MORE TRAPS OR MOVE SPEAKERS/SUBS AROUND, THIS WILL GET SMALLER, AND THE GOAL IS TO GET ALL THE FREQUENCIES WITHIN 10% OR AS CLOSE AS POSSIBLE TO EACH OTHER AND BE ABLE TO EVENTUALLY VIEW EVERYTHING ON THE GRAPH AT NO MORE THAN 600MS MAXIMUM, PREFERABLY CLOSER TO 400MS.
 
Q: Once I know what I am looking at, what are the various methods to address the problems? Should I go out and buy a roll of pink fluffy? 
 
A: Once you understand that there will certainly be peaks in the ETC, ringing in the waterfall, and uneven frequency response both before and after Room EQ software is engaged, you have to determine where to begin.
 
The best place to begin is with moving your sub(s) and listening position, even just a few inches at a time, being sure to measure and notate the exact locations of each speaker and your listening position on each measurement.
 
TIP: BE SURE TO “SAVE ALL MEASUREMENTS” IN REW – THIS WAY THE .MDAT FILES CAN BE SHARED WITH OTHER USERS AND YOU CAN RECALL THEM LATER.
 
Then, once you’ve found the best speaker and listening position, the best place to begin as far as treatment is concerned is with bass trapping. Although there are several different types of traps, IE: Helmholtz, Membrane, Slotted, etc, the most common (and affordable) type you will see for sale is of the fuzzy breed also referred to as “Pink Fluffy.” This is basically household insulation like R30 or specialty insulation most often used by HVAC contractors for air conditioning duct work, commonly referred to as “OC 703” or “OC 705.” These types of insulation/bass traps are resistive and worked based on the relationship between the Gas (air) Flow Resistance and the thickness.
 
TIP: 4” “BASS TRAPS” COMMONLY SOLD FOR $75 - $250EA ARE “NOT” BASS TRAPS!!! AT BEST THEY ARE BROADBAND ACOUSTICAL PANELS.
 
A common question is, “Is thicker better?” NOT ALWAYS. For instance, a common design touted amongst the forums is the “SuperChunk.” This is commonly prescribed as a minimum of 17” x 17” x 24” triangles stacked up in the corners of your room. Unfortunately, while this does work, it would work much better and be much cheaper if a much lower GFR material, for instance R-30 which is approximately 5000 Rayl/s were used instead of the commonly used OC 703 (or variant) which is somewhere above 30000 Rayls.
 
We’ll talk much more about this on the thread, but a good rule of thumb is, if you have the space, thicker traps (from about 8” and thicker) work better with lighter, fluffier, common insulation like R-30 attic insulation but if you have less than 8” to work with, OC 703 or Roxul Safe N Sound (20,000 Rayl/s or so and now available at most Lowe’s stores) with a higher GFR work better in the lower frequencies.
 
It’s all relative and there is no one size fits all answer, but I assure you that thicker/bigger is not always better. For the folks that spent a lot of money on OC 703 to make triangles/SuperChunk style, pull it out…Use it for broadband panels, and replace with “Pink Fluffy” as 17” thick traps made from OC 703 (36,000 Rayl/s or so) or heaven forbid someone that went all out and used OC 705 (60,000 Rayl/s or so) and made the 24” thick (34” wide) larger variant have simply wasted a lot of money. While these “traps” will perform, they won’t perform nearly as well as a properly sized trap vs its GFR will.
 
A great tool which is free, easy to use, and requires no download/installation to see exactly how your traps perform (you can model 4 different sizes/types of trap at the same time to see what will work best with the space and budget you have) is at - This is a very powerful Porous Absorber Calculator, is very accurate, and is what I use in designing/building Porous traps (traps made from insulation).
 
TIP: ANY “BASS TRAP” YOU WILL SEE FOR SALE BETWEEN $75 AND $200 IS NOTHING MORE THAN INSULATION WRAPPED IN CLOTH. IF YOU USE THIS FORUM, USE THE CALCULATER MENTIONED ABOVE, AND HAVE EXTREMELY BASIC DIY SKILLS, YOU CAN VERY EASILY BUILD ALL OF YOUR OWN ACOUSTIC PANELS AND BASS TRAPS FOR ABOUT 5% TO 10% OF THE COST OF PURCHASING, PLUS THEY WILL BE CUSTOM FITTED AND YOU’LL HAVE LEARNED A LOT. IF, HOWEVER, YOU HAVE MORE MONEY THAN TIME, WELL… YOU PROBABLY AREN’T READING THIS TO BEGIN WITH. 
 
I plan to add to this post as other topics, FAQ’s, etc come up, so please check back to the first page often as there will be updated information appearing here as time permits and if requested, or as long as the thread stays active.
 
Thanks for reading and I hope this helps…
 
--Jason
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post #119 of 10741 Old 01-08-2013, 12:31 PM
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Jason - when you have finished with the above post, let me know and I will delete it, along with this one.

 

One suggestion - don't use caps for complete phrases or sentences -- caps are harder to read than upper and lower case text and put people off. I have left them as they were because the AVS editor doesn't allow me to easily change them. If I had had more foresight I would have copied it into Word first, then changed the caps en masse to u/lc and then pasted it to my test editor and then finally to the AVS editor.

 

Don't worry too much about format at this stage - let's get the meat of it sorted and then I can format it all, create hyperlinks etc when I start the FAQ proper.

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post #120 of 10741 Old 01-08-2013, 12:43 PM
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Quote:
Originally Posted by kbarnes701 View Post

Feri, can you elaborate for me please?  Where do I set the test signal volume? WIth the discussion in Post 2 about using 100dB for the test signals (I think my house might fall down with 100dB from my two Submersives - LOL) I am cautious about the test tone volume. Any help you can give would be appreciated.

Keith, I really wouldn't like to go ahead of Jason, I'm sure he will include this part in his descriptions when time comes.

Nonetheless, here are some of my own thoughts:

1. Test level/volume can be set either in REW or on the MV of the AVR/AVP depending on the type of measurements one would like to conduct.

2. Volume/level for testing our rooms to find out anomalies prior to running room eq should not be critical, although REW will check and advise on too low (near the noise floor) or too high (near to clipping) volumes prior to measuring.

3. This will become interesting when we engage MultEQ and especially DEQ, because these twins will need calibrated SPLs vs. test signal levels. Remember the good old equation where -30 dBfs is supposed to render a 75 dB SPL at the MLP. Now if you feed 0 dBfs into the system the SPL at the MLP should be exactly 105 dB for satellites and with the +10 dB boost of the LFE the Submersives should deliver in your room a total of 115 dB SPL (flat). What did you say about rattling in your room? Yikes! With a 115 dB SPL at 10 Hz you will have one final rattle in your room before it falls down. Household insurance policy OK? Make sure REW tests are included in All Risks clause! tongue.gif

So, let's wait for Jason to guide us on these fine details. wink.gif
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