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# Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How... - Page 53

Quote:
Originally Posted by kbarnes701

OK guys - question... I was about to do the 'string thing', despite Mrs Keith looking on incredulously as I measure and prepare to cut a length of string

Here is the ETC of my centre speaker (Audyssey is on):

It shows a couple of nasty spikes. The first is at 1.44ms and the second is at 4.76ms. Using the formula on p63 of Jerry's guide gives me the following:

1.44 x 13.39722 is 19.29 inches, or 1.60 feet.

4.76 x 13.39722 is 63.77 inches, or 5.3142 feet.

Multiplying those by 1.13 gives me a total reflection distance of 1.82 feet and 6.00 feet respectively.

The problem is, in my room, it is impossible to have a reflective surface at those distances, given that the MLP (and thus the mic) is approx 9.5 feet from the centre speaker.

What am I missing before I break out my new ball of string delivered so efficiently by Amazon Prime yesterday?

EDIT: The example in the Guide doesn't make much sense either, because it shows a calculated distance of 8.6 feet and, again, that is way too short a distance from the speaker to the reflective point and then on to the mic. Something seems to be amiss...

Make the string:

9.5 + 1.60 = 11.1 feet and stretch to see where it will touch.

also

9.5 + 5.3 = 14.8 feet

see if that helps you identify.

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As I said, I am re-working the instructions.  You need to add the actual distance from your speaker to the mic at the MLP to the distance you derive from the ETC graph (you can use the Audyssey-calculated distance).  Would that make more sense?

Here are the original instructions from Jason:

If your first reflection is at 8.1ft (not 8.1ms, right, but you used the right mouse button, pointed at 0, then dragged all the way over to the first spike while holding down the CTRL key, right?? That's how you convert the ms into feet. REW does it for you as long as you use this technique) that means the total path length, IN ADDITION TO the time it took for the direct sound to get to you (which has no reflections and is shown as the initial spike at 0 in REW) is 8.1ft.

So then what you have to do is (you can imagine this after you get some practice in and then verify you've taken care of it by running another ETC and seeing if the spike is gone) cut a piece of string.

You determine the length of the string by Adding the ACTUAL distance between the microphone and the mid-range driver of your speaker to this 8.1ft measurement.

Then attach one end at the mic, without moving it (it's okay to make the string longer to give you a place to tie it to at both ends, but be sure and mark on it the actual starting point at 0.0'/at mic and the actual 8.1ft+distance between mic and mid-range driver) and the other end to a tri-pod or other temporary device to hold the other end as close to the mid-range driver (including the height of it - literally right in front of it as close as you can get without touching it/damaging the driver) then pull the string taught.

With the string pulled taught simply move the string around, keeping it taught, in all directions until it touches a hard reflective surface. When it does (this isn't necessarily "exact" but pretty darn close, so if the string touches a surface but isn't totally taught or if it "almost" touches a surface but doesn't quite reach, that could still be your culprit) you've found the culprit.

I apologize for the original wrong instructions--ETC graphs are not easy for me.

Quote:
Originally Posted by AustinJerry

Keith,

I went back and looked at my notes, and that section in the ETC guide is wrong.  The proper way to determine the distance of a peak is to place the cursor vertically on zero, hold the Control Key down, click the right mouse button, and drag the cursor to the peak you want to measure.  Here is an example:

I will edit that section in the guide--don't know where that mistake came from!

Do we still multiply by 1.13 after this to get the actual distance?
Quote:
Originally Posted by Pres2play

Anechoic,how exactly did you get the mic to work?

Gah, I was afraid someone would ask.
Quote:
From earlier posts, I assumed the problem had to do with the way and order the mic is connected, i.e., plug in mic before powerup.

I actually have an issue with my laptop that if a UMM-6 is connected when the power is off, the machine will hang during bootup. I'm running Windows 7 64-bit under Bootcamp on a MacBook Air so that could be an issue with Windows, the Mac, EFI, or all of the above. But if I plug in the mic after it's booted up, everything is fine.

Quote:
If you remedied the problem with the sound control panel instead, can I ask you which driver did you use? Java or ASIO? I used ASIO and maybe the issue is there.

I don't see where, in REW (v5), you have a choice. In ARTA I use the WDM driver, ASIO has always given me problems.
Quote:
Originally Posted by NicksHitachi

Quote:
Originally Posted by kbarnes701

OK guys - question... I was about to do the 'string thing', despite Mrs Keith looking on incredulously as I measure and prepare to cut a length of string

Here is the ETC of my centre speaker (Audyssey is on):

It shows a couple of nasty spikes. The first is at 1.44ms and the second is at 4.76ms. Using the formula on p63 of Jerry's guide gives me the following:

1.44 x 13.39722 is 19.29 inches, or 1.60 feet.

4.76 x 13.39722 is 63.77 inches, or 5.3142 feet.

Multiplying those by 1.13 gives me a total reflection distance of 1.82 feet and 6.00 feet respectively.

The problem is, in my room, it is impossible to have a reflective surface at those distances, given that the MLP (and thus the mic) is approx 9.5 feet from the centre speaker.

What am I missing before I break out my new ball of string delivered so efficiently by Amazon Prime yesterday?

EDIT: The example in the Guide doesn't make much sense either, because it shows a calculated distance of 8.6 feet and, again, that is way too short a distance from the speaker to the reflective point and then on to the mic. Something seems to be amiss...

Make the string:

9.5 + 1.60 = 11.1 feet and stretch to see where it will touch.

also

9.5 + 5.3 = 14.8 feet

see if that helps you identify.

Quote:
Originally Posted by AustinJerry

As I said, I am re-working the instructions.  You need to add the actual distance from your speaker to the mic at the MLP to the distance you derive from the ETC graph (you can use the Audyssey-calculated distance).  Would that make more sense?

Here are the original instructions from Jason:

If your first reflection is at 8.1ft (not 8.1ms, right, but you used the right mouse button, pointed at 0, then dragged all the way over to the first spike while holding down the CTRL key, right?? That's how you convert the ms into feet. REW does it for you as long as you use this technique) that means the total path length, IN ADDITION TO the time it took for the direct sound to get to you (which has no reflections and is shown as the initial spike at 0 in REW) is 8.1ft.

So then what you have to do is (you can imagine this after you get some practice in and then verify you've taken care of it by running another ETC and seeing if the spike is gone) cut a piece of string.

You determine the length of the string by Adding the ACTUAL distance between the microphone and the mid-range driver of your speaker to this 8.1ft measurement.

Then attach one end at the mic, without moving it (it's okay to make the string longer to give you a place to tie it to at both ends, but be sure and mark on it the actual starting point at 0.0'/at mic and the actual 8.1ft+distance between mic and mid-range driver) and the other end to a tri-pod or other temporary device to hold the other end as close to the mid-range driver (including the height of it - literally right in front of it as close as you can get without touching it/damaging the driver) then pull the string taught.

With the string pulled taught simply move the string around, keeping it taught, in all directions until it touches a hard reflective surface. When it does (this isn't necessarily "exact" but pretty darn close, so if the string touches a surface but isn't totally taught or if it "almost" touches a surface but doesn't quite reach, that could still be your culprit) you've found the culprit.

I apologize for the original wrong instructions--ETC graphs are not easy for me.

BINGO!!!

Thanks guys. Jerry, I look forward to the revised version of the Guide when you get the chance....

Gentlemen,
That practical group discussion above >> just made ETC come into focus for me!!
Seriously that was a relatively short read that puts it into perspective

So just a few more questions (for kbarnes):
What did you find at 11.1 and 14.5 feet ??
I'm now off to Amazon Prime for some special string >>>> what "coefficient of stretch" is best to order?
Quote:

BINGO!!!

Thanks guys. Jerry, I look forward to the revised version of the Guide when you get the chance....

So, Keith, with this new bit of information, what distances are you looking at now?  Are they more realistic?

Quote:
Originally Posted by cuzed2

Gentlemen,
That practical group discussion above >> just made ETC come into focus for me!!
Seriously that was a relatively short read that puts it into perspective

So just a few more questions (for kbarnes):
What did you find at 11.1 and 14.5 feet ??
I'm now off to Amazon Prime for some special string >>>> what "coefficient of stretch" is best to order?

I haven't done the string thing yet (it's 10pm here now so I'll leave it till tomorrow) but I am guessing that the centre channel is reflecting off the ceiling (the other candidates are already treated). I also have to do the string thing for my L and R channels (where I again think I know the issues). I'll post the results.

Quote:
Originally Posted by AustinJerry

Quote:

BINGO!!!

Thanks guys. Jerry, I look forward to the revised version of the Guide when you get the chance....

So, Keith, with this new bit of information, what distances are you looking at now?  Are they more realistic?

Yes, Jerry - much better - see my last post.

Quote:
Originally Posted by kbarnes701

FWIW, I had various problems getting Windows/REW to recognise the mic until I adopted a standard sequence for setting it up. This is:
1. Plug in mic and HDMI cables to laptop and AVR
2. Power on laptop
3. Power on AVR
4. Start REW

I always use that sequence now and it has worked every time - both my UMM-6 and Onkyo 5509 are recognised when REW runs.

Thanks, Keith. I will try this when the mic arrives.
Quote:
Originally Posted by kbarnes701

Quote:
Originally Posted by cuzed2

Gentlemen,
That practical group discussion above >> just made ETC come into focus for me!!
Seriously that was a relatively short read that puts it into perspective

So just a few more questions (for kbarnes):
What did you find at 11.1 and 14.5 feet ??
I'm now off to Amazon Prime for some special string >>>> what "coefficient of stretch" is best to order?

I haven't done the string thing yet (it's 10pm here now so I'll leave it till tomorrow) but I am guessing that the centre channel is reflecting off the ceiling (the other candidates are already treated). I also have to do the string thing for my L and R channels (where I again think I know the issues). I'll post the results.

Remember, any speaker can reflect off of any wall.  So the left and right speakers may have a ceiling reflection, and the center may have sidewall reflections.

Version 2.5 of the REW Guide has been posted.

Changes in this version are:

• Updated ETC section by correcting the distance calculation instructions.
• Updated the Pre-Out measurement section to include instructions on creating a microphone calibration file.
• Updated the Measurements Guidelines section with note on how users with 8-channel capable set-ups should configure tests that include sub(s).
• Revised Taking REW Measurements, Section 15.b (page 56) referring to instructions for generating an average.

Edited by AustinJerry - 2/21/13 at 3:02pm
Quote:
Originally Posted by Anechoic

Quote:
Originally Posted by Pres2play

Anechoic,how exactly did you get the mic to work?

Gah, I was afraid someone would ask.
Quote:
From earlier posts, I assumed the problem had to do with the way and order the mic is connected, i.e., plug in mic before powerup.

I actually have an issue with my laptop that if a UMM-6 is connected when the power is off, the machine will hang during bootup. I'm running Windows 7 64-bit under Bootcamp on a MacBook Air so that could be an issue with Windows, the Mac, EFI, or all of the above. But if I plug in the mic after it's booted up, everything is fine.

Quote:
If you remedied the problem with the sound control panel instead, can I ask you which driver did you use? Java or ASIO? I used ASIO and maybe the issue is there.

I don't see where, in REW (v5), you have a choice. In ARTA I use the WDM driver, ASIO has always given me problems.

I don't mean any disrespect, but I think you should have revealed to use that you were running REW under Bootcamp on a Mac.  That is clearly a different configuration than most of us are running, and is likely to have a unique set of problems that we would be unaware of.

Quote:
Originally Posted by AustinJerry

I don't mean any disrespect, but I think you should have revealed to use that you were running REW under Bootcamp on a Mac.  That is clearly a different configuration than most of us are running, and is likely to have a unique set of problems that we would be unaware of.

It shouldn't be an issue, Jerry. All that Bootcamp does is to allow Windows to run on an Intel Mac. It's just a normal copy of Windows running on an Intel processor.

Quote:
Originally Posted by AustinJerry

I don't mean any disrespect, but I think you should have revealed to use that you were running REW under Bootcamp on a Mac.  That is clearly a different configuration than most of us are running, and is likely to have a unique set of problems that we would be unaware of.

What kbarnes701 said. Bootcamp isn't a VM, Windows is directly running on the hardware, same as on a Dell/HP/etc. The biggest difference is that Windows under Bootcamp uses specific Apple drivers to access specialty hardware like the Mac trackpad and the Thunderbolt interface (which BTW have not been a problem - a Thunderbolt -to-Fireware adapter works perfectly well with my Presonus Firebox) but won't effect common interfaces like USB, and the low-level startup sequence might be different since Mac's use EFI rather than BIOS, which is why I think the laptop won't boot when the UMM-6 is connected.
Quote:
Originally Posted by AustinJerry

Quote:
Originally Posted by kbarnes701

Quote:
Originally Posted by cuzed2

Gentlemen,
That practical group discussion above >> just made ETC come into focus for me!!
Seriously that was a relatively short read that puts it into perspective

So just a few more questions (for kbarnes):
What did you find at 11.1 and 14.5 feet ??
I'm now off to Amazon Prime for some special string >>>> what "coefficient of stretch" is best to order?

I haven't done the string thing yet (it's 10pm here now so I'll leave it till tomorrow) but I am guessing that the centre channel is reflecting off the ceiling (the other candidates are already treated). I also have to do the string thing for my L and R channels (where I again think I know the issues). I'll post the results.

Remember, any speaker can reflect off of any wall.  So the left and right speakers may have a ceiling reflection, and the center may have sidewall reflections.

Oh sure. I was just meaning that the other likely candidates are already treated. I will apply the string thing to every possible place, have no fear :)

Quote:
Originally Posted by Anechoic

Gah, I was afraid someone would ask.
I actually have an issue with my laptop that if a UMM-6 is connected when the power is off, the machine will hang during bootup. I'm running Windows 7 64-bit under Bootcamp on a MacBook Air so that could be an issue with Windows, the Mac, EFI, or all of the above. But if I plug in the mic after it's booted up, everything is fine.
I don't see where, in REW (v5), you have a choice. In ARTA I use the WDM driver, ASIO has always given me problems.

Thank you for that info about your setup. WRT ASIO, anyone using HDMI output with REW must also use ASIO4ALL as their driver. It's selectable in the REW soundcard tab, once it's installed.
Edited by Pres2play - 2/21/13 at 7:24pm
Quote:
Originally Posted by Anechoic

Gah, I was afraid someone would ask.
I actually have an issue with my laptop that if a UMM-6 is connected when the power is off, the machine will hang during bootup. I'm running Windows 7 64-bit under Bootcamp on a MacBook Air so that could be an issue with Windows, the Mac, EFI, or all of the above. But if I plug in the mic after it's booted up, everything is fine.
I don't see where, in REW (v5), you have a choice. In ARTA I use tWDM driver,er, ASIO has always given me problems.

Quote:
Originally Posted by Pres2play

Thank you for that info about your setup. WRT ASIO, anyone using HDMI output with REW must also use ASIO4ALL as their driver. It's selectable in the REW soundcard tab, once it's installed.

Anechoic, are you sure you have Java Run Time Environment on that Mac in Windows7? REW needs RTE to work. That might be the reason ARTA and HomeImpulse work on your Mac, and not REW. I'm not at home right now to check this out, but I do know I deleted RTE from my laptop when I downloaded Java 7, a day before I got the mic. Damn popups can confuse you. I bet RTE is missing from my PC too. Can't wait to get home.
Quote:
Originally Posted by Pres2play

Anechoic, are you sure you have Java Run Time Environment on that Mac in Windows7? REW needs RTE to work. That might be the reason ARTA and HomeImpulse work on your Mac, and not REW. I'm not at home right now to check this out, but I do know I deleted RTE from my laptop when I downloaded Java 7, a day before I got the mic. Damn popups can confuse you. I bet RTE is missing from my PC too. Can't wait to get home.

REW works fine. The issue I had (since resolved) was getting REW to work with UMM-6 mics.
Quote:
Originally Posted by Anechoic

REW works fine. The issue I had (since resolved) was getting REW to work with UMM-6 mics.

Yes, that's what I meant. Sorry.
Well, Java Run Time Environment (correct abbreviation JRE!) is just an older version of Java 7, and they recommend you uninstall it, so no harm there I guess.
Hello:)
I have a problem, perhaps it's already explained in this forum but I could not find it:
When I try to choose "Input" on REW soundcard page, there is no option to choose UMM-6.
On ASIO controll page the UMM-6 is IDLE while the Realtek High Defenition Audio is Active.
How do I change that?
Quote:

Quote:
Originally Posted by kbarnes701

You could always fix it the professional way: gaffer tape

Well after the glue dried. I attempted to use the mic & didn't work. I think i might have pulled one of the three wires lose when trying to fix it.

That's a bummer for sure. Is it not possible to reconnect the wire?

Quote:
Originally Posted by AVRams

Hello:)
I have a problem, perhaps it's already explained in this forum but I could not find it:
When I try to choose "Input" on REW soundcard page, there is no option to choose UMM-6.
On ASIO controll page the UMM-6 is IDLE while the Realtek High Defenition Audio is Active.
How do I change that?

That happened to me the first time I tried to use it. Much plugging and unplugging, shutting down and restarting, connecting and disconnecting in random orders, connecting the mic without HDMI connected and vice-versa later, it all started to work and has done so since. I didn't even need to use the incantation.

When you plug the mic in, did you get the little Windows popup about installing drivers etc?  Also, it can, apparently, take up to 60 seconds for Windows to recognise a USB mic, but I guess if it is showing in ASIO that Windows knows it's there.

Quote:
Originally Posted by AVRams

Hello:)
I have a problem, perhaps it's already explained in this forum but I could not find it:
When I try to choose "Input" on REW soundcard page, there is no option to choose UMM-6.
On ASIO controll page the UMM-6 is IDLE while the Realtek High Defenition Audio is Active.
How do I change that?

Hi AVRams, when this happen on me all I did (after selecting UMM-6 in ASIO Control) is to close REW and re-open REW then it will show "Active".
Quote:
Originally Posted by Pres2play

Well, Java Run Time Environment (correct abbreviation JRE!) is just an older version of Java 7, and they recommend you uninstall it, so no harm there I guess.

Like I said, the issue was the settings in the sound control panel.
Anyone have any luck using the internal mic input on a MacBook pro? My initial experiment seems to show its not accurate enough. I'm getting hills and valleys with a swing of close to 20 dB (from 95 Hz to 20 kHz)... when the receiver is in pure audio mode.

This is measuring the pre-out (right).

Many of the steps in the guide don't apply to the Mac setup, so it's possible I didn't substitute them with something appropriate.

I'll search again in this forum, in case I missed it. (FWIW, I think the search here is pretty poor --- it provides the smallest preview of the posts possible and often seems to spent most of the space with tags)

Thanks in advance for any insight....
Quote:

Anyone have any luck using the internal mic input on a MacBook pro? My initial experiment seems to show its not accurate enough. I'm getting hills and valleys with a swing of close to 20 dB (from 95 Hz to 20 kHz)... when the receiver is in pure audio mode.
My mic in on Dell is totally inadequate also for pre-out measurements... So I am using external ADC.
But might be this could help you, how many sweeps you do when measuring? If more than one, then set it to just one.
Took some measurements with Audyssey engaged. Subs only, no smoothing, dynamic EQ engaged and no boost added.

Left speaker and subs, Audyssey and dynamic EQ. 1/6 smoothing.

Edited by AV Science Sales 5 - 2/23/13 at 7:39pm
Quote:

Anyone have any luck using the internal mic input on a MacBook pro? My initial experiment seems to show its not accurate enough. I'm getting hills and valleys with a swing of close to 20 dB (from 95 Hz to 20 kHz)... when the receiver is in pure audio mode.

This is measuring the pre-out (right).

Many of the steps in the guide don't apply to the Mac setup, so it's possible I didn't substitute them with something appropriate.

I'll search again in this forum, in case I missed it. (FWIW, I think the search here is pretty poor --- it provides the smallest preview of the posts possible and often seems to spent most of the space with tags)

Thanks in advance for any insight....

I used to use a Mac Book Pro with a calibrated mic and I got good readings using REW. This was back when I used a Behringer MIC2200 mic preamp and calibrated XLR mic. Back then was not using HDMI output on the laptop, used the analog audio outputs and loop back measurement for calibration.
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