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Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How... - Page 36

post #1051 of 9622
Quote:
Originally Posted by AustinJerry View Post

What level did you set in the Windows Audio Recording device screen?

Edit:  What mic are you using?
I do own the UMM-6 & in Windows 8 the mic level is at 100%. I have'nt had time to do a full setup at my mlp, but I plugged in the mic & my 20' hdmi cable in & went through the setup to verify that everything would work as anticipated. I was aprox. 3' from the front speaker & had to crank the avr up to -15 just to get rew to start to register(I was checking the levels in REW). I had my toddlers in the room with me, so I didn't want to get carried away. I will do a "true" setup this weekend. Just to note, REW was at default & sending the signal at -12db. I might have to raise this closet to -3db. Also in ASIO I noticed there was a checkbox for resampling 44 to 48 or vice versa(not looking at it right now). Should this be checked?

Gear mentioned in this thread:

post #1052 of 9622

Re: 44 vs 48, you just want to make sure whatever sample rate you choose matches in REW.

post #1053 of 9622
Quote:
Originally Posted by Alan P View Post

My mic will be here tomorrow, YEAH! I get to spend all weekend annoying the wife and dogs with sweeps! cool.gif

 

Mine hasn’t even made it to the UK yet - after almost 2 weeks. :(

post #1054 of 9622
The setting that I'm referring to is within the ASIO control panel(I'm not familiar with this program). The sample rate in windows does match whats in REW.
post #1055 of 9622
Quote:
Originally Posted by cadett View Post


(I was checking the levels in REW). 
 
Also in ASIO I noticed there was a checkbox for resampling 44 to 48 or vice versa(not looking at it right now). Should this be checked?

 

Re: checking the levels in REW.  Remember, you must calibrate the microphone to a known external level measuring device like an SPL.  With my AVR MV at -15, the sound level at the MLP measures 80dB.  As an exercise, open the REW SPL, set the AVR MV to -15, generate the sub test tone, enter 80dB in the Set SPL Level box, and click close.  Now see if the microphone level is still too low.

 

The ASIO resample button has no effect, as long as both your input and output have been configured to 48K sampling rates (in Windows Audio).

post #1056 of 9622
Quote:
Originally Posted by AustinJerry View Post

Re: checking the levels in REW.  Remember, you must calibrate the microphone to a known external level measuring device like an SPL.  With my AVR MV at -15, the sound level at the MLP measures 80dB.  As an exercise, open the REW SPL, set the AVR MV to -15, generate the sub test tone, enter 80dB in the Set SPL Level box, and click close.  Now see if the microphone level is still too low.

Will do. I'll see if that has any effect on the clipping meter when I go to check the levels. If that is the case, then once you have the HD audio set as output & the UMM-6 selected as input, you will need to set the spl level before, you actually check the levels in REW. If this has already been stated in the guide, please excuse my misread.

Quote:
The ASIO resample button has no effect, as long as both your input and output have been configured to 48K sampling rates (in Windows Audio).

Good to know, thanks.
post #1057 of 9622

I have been experimenting quite a bit with the UMM-6 microphone and the HDMI connection over the past several days.  Some notes I captured during the testing:

 

  • The simplified REW kit consisting of the USB mic and HDMI cable is considerably easier to set up.  So much nicer than the legacy kit.
  • When compared with measurements using the legacy EMM-6, measurements using the new kit are consistent, indicating that the kit is working properly.  I used the 90-degree calibration file for both mics.  I didn’t compare readings using the 0-degree calibration file to see how much of a difference there would be.
  • When using HDMI, the Windows Audio Playback Device output level does not seem to make a difference.  When this level was set to zero, HDMI output was unaffected.  I’ll make a note of this in the guide.
  • When using HDMI, the Windows Desktop is output to the TV monitor.  On my hardware, this would consistently result in a magenta-colored desktop on the monitor.  Sometimes, by forcing an HDMI handshake by unplugging and re-inserting the cable, or by power-cycling the AVR, this would clear up.  Other times, the magenta color would persist.  It is annoying, but in no way impacts the functionality of REW.  I spent a bit of time trouble-shooting with various settings with no success.
  • With HDMI, I would occasionally get a crackling static sound from the HDMI audio when running a measurement sweep.  Re-setting the HDMI connection consistently cleared up the problem.  I’ll try a different cable as well, but this was a non-issue.
  • I noticed that the noise threshold, when measured by the UMM-6, was higher than when measured by the EMM-6.  With the old mic, the threshold was ~40dB, and with the USB mic it is closer to 50dB.  This is perplexing, because my house seems to be dead quiet (to me, at least).  I am at a loss with regards to what might be causing low frequency, inaudible sound that would affect the noise floor.

 

I’m looking forward to others starting their USB mic testing.  If you notice any of the issues I have listed above, please report in this thread.

 

 

Here are my most recent measurements:

 

 

 

 

 

 

 


Edited by AustinJerry - 2/8/13 at 2:55pm
post #1058 of 9622

I got my UMM-6 mic this week and I'm planning a marathon measuring session (minus HDMI) tomorrow so get ready! biggrin.gif

post #1059 of 9622
Should have my mic tomorrow, will be testing as well.
post #1060 of 9622

BTW, I heard someone say that the OmniMic looks just like the pictures I posted of the UMM-6.  If that is the case, and the microphone is actually the same one, then the UMM-6 calibration files might be "close enough" for use with the OmniMic.  I could post the calibration files here if anyone wants to test them out.

 

Edit:  Or perhaps Keith would be kind enough to test the OmniMic against the UMM-6, using the same calibration file for both.  Keith, you haven't parted with your OmniMic yet, have you?

post #1061 of 9622

^^^^Yeah, I think that was me!  The kit is identical now that I have received my UMM-6 (I was basing it off of your pictures) but I had to return my OM before the UMM-6 arrived.  It's essentially the same mic except black instead of silver.  All of the accessories are identical.  I was wondering if someone would be able to get OM working with the UMM-6?  Would be an interesting dilemma for OM...the thing I still don't understand is that Jason said the OM cal file is for the 0 degree position except everyone in the OM thread (including our very own KB) is measuring with the mic pointing at the ceiling?? confused.gif

post #1062 of 9622
Quote:
Originally Posted by jkasanic View Post

....the thing I still don't understand is that Jason said the OM cal file is for the 0 degree position except everyone in the OM thread (including our very own KB) is measuring with the mic pointing at the ceiling?? confused.gif

My guess is that's because my fellow (former) OmniMic users never thought about needing a specifically 90 degree calibration file any more than either of us did until two months ago. Or maybe Bill Waslo's opinion was that it wasn't strictly neccessary.

We're also onto a higher level of rigor here. Learning/experimenting with REW's feature set and more flexible measurement due to the newish USB mic/HDMI capacity is kind of the point. Otherwise I'm not sure switching measurement software for the sake of switching is enough by itself. And it's not like we're providing much of a revenue stream to anyone by a group move to REW (it and ASIO4ALL are free, and the new USB mics are relatively trivial as A/V purchases go).

BTW I'm keeping my OmniMic regardless. You never know what a future release might bring. It might even help take the OmniMic thread out of its typical dormancy.
Edited by sdrucker - 2/8/13 at 7:34pm
post #1063 of 9622
Quote:
Originally Posted by AustinJerry View Post

I have been experimenting quite a bit with the UMM-6 microphone and the HDMI connection over the past several days.  Some notes I captured during the testing:

 

 

  • When using HDMI, the Windows Desktop is output to the TV monitor.  On my hardware, this would consistently result in a magenta-colored desktop on the monitor.  Sometimes, by forcing an HDMI handshake by unplugging and re-inserting the cable, or by power-cycling the AVR, this would clear up.  Other times, the magenta color would persist.  It is annoying, but in no way impacts the functionality of REW.  I spent a bit of time trouble-shooting with various settings with no success.

 

 

 

Good report, Jerry. WRT to the above, I am getting the Windows desktop displayed correctly on my 65 inch Panasonic VT50, although the aspect ratio is incorrect. That would be easy to correct but I can't be bothered to do so. In fact, there's no need to have the screen on during REW testing is there? I guess it is one of those perennial HDMI handshake/compatibility issues and you could probably track it down and fix it if you were motivated to do so. Personally, I wouldn't bother and would just turn the TV off.

 

Other than that, your initial run has been a success, I'd say?

post #1064 of 9622
Quote:
Originally Posted by AustinJerry View Post

BTW, I heard someone say that the OmniMic looks just like the pictures I posted of the UMM-6.  If that is the case, and the microphone is actually the same one, then the UMM-6 calibration files might be "close enough" for use with the OmniMic.  I could post the calibration files here if anyone wants to test them out.

 

Edit:  Or perhaps Keith would be kind enough to test the OmniMic against the UMM-6, using the same calibration file for both.  Keith, you haven't parted with your OmniMic yet, have you?

 

I still have my OM but mine is version 1 and doesn't come with a cal file. 

post #1065 of 9622
Quote:
Originally Posted by jkasanic View Post

^^^^Yeah, I think that was me!  The kit is identical now that I have received my UMM-6 (I was basing it off of your pictures) but I had to return my OM before the UMM-6 arrived.  It's essentially the same mic except black instead of silver.  All of the accessories are identical.  I was wondering if someone would be able to get OM working with the UMM-6?  Would be an interesting dilemma for OM...the thing I still don't understand is that Jason said the OM cal file is for the 0 degree position except everyone in the OM thread (including our very own KB) is measuring with the mic pointing at the ceiling?? confused.gif

 

My ver 1 doesn't come with a cal file. You have to enter a serial number into the OM software. Vertical orientation is correct for ver 1 mics. Can't comment on ver 2 unfortunately.

post #1066 of 9622
Quote:
Originally Posted by kbarnes701 View Post

My ver 1 doesn't come with a cal file. You have to enter a serial number into the OM software. Vertical orientation is correct for ver 1 mics. Can't comment on ver 2 unfortunately.

While the OM V.2 calibration is only for on axis measurement, there is "sens factor" given in the calibration file. This leads me to think that REW could use the Sens factor data to eliminate the need for a separate measurement with a SLM..
post #1067 of 9622

Ok, have an issue with the SPL calibration.  Following the guide, it says the output signal should only be coming from the left speaker but my sub is also playing the test tone (note, I"m not using HDMI, only 3.5mm stereo to RCA cable with Y adapter from right channel to L and R on Aux input on prepro):

 

 

 

I'm guessing this is because I chose the REW subwoofer cal signal (but still not sure why sound was playing from both sub and left channel?).  I switched to REW speaker cal signal and the sub was quiet so not sure if I did something wrong or if the guide needs to be re-stated?

 

EDIT:  Also, my max SPL calibration came in at 132 dB (12 dB over Jerry's suggested 90-120 dB range) with MV on my Integra DHC-80.3 set at -11 to get 80dB at the MLP with only the left channel playing.

 

EDIT 2:  After not getting a good headroom number, I noticed a difference when I was "re-doing" the setup for REW.  I previously had "Control input mixer volume checked" and the input volume was set to 0.75:

 

 

I recalibrated SPL and got my max SPL calibration number down to 120 and headroom was acceptable as well.  Hopefully, somebody will respond before I take a bunch of bad measurements!

 

EDIT 3:  Ok, must be doing something wrong as I'm getting all kinds of errors I haven't seen before.  This one is when I try to measure the left speaker without the sub:

 


Edited by jkasanic - 2/9/13 at 1:39pm
post #1068 of 9622

^

 

If you are using the HDMI cable and have selected the left channel as the output, remember that bass management will route low frequency signals below the crossover point to the sub(s), especiallly if you use the subwoofer test tone.  There is nothing wrong with this.  I use the subwoofer test tone as well, but the speaker-level test tone should produce similar results (although little or no signal will be re-directed to the sub(s)).

 

The "Control input mixer volume" should not be checked.  This means the microphone input level will be controlled by the Windows Audio Recording Device level setting, which I currently have set to 100%.

 

When you achieve an 80dB reading on the SPL at the MLP, input the 80dB value into the SPL Level Input box, and click finished, you will get a maximum headroom information pop-up message.  This can vary, and I don't see anything wrong with your value of 120.  When running a sweep measurement, the headroom is displayed, and as long as it is "green" you are OK.  I believe it will be green if the headroom is in the range of -20 to -5dB.

 

I would go ahead and take a couple of measurements, say L+R with both Audyssey off and Audyssey on, post the results here, and let's see what you have.  You seem to be making good progress.

post #1069 of 9622

@AJ:  Make sure you read my edits above.  No HDMI cable and some weird behavior with my mic thus far.

 

Ok, here's L+R+Sub with and without Audyssey:

 

 

 

I'm still not sure I did the SPL calibration correctly.  I did uncheck "Control Input Mixer Volume" but I didn't do another SPL calibration.  Judging by where my measurements are centered...I'm guessing I need to?

 

EDIT:  Quiet room measurements are like 55 dB.  I was closer to 45 with my OM mic?  I'm wondering if my Ratshack 33-2055 SPL is suspect?!

 

EDIT 2:  Changed smoothing to 1/6th per AJ post below.


Edited by jkasanic - 2/9/13 at 2:54pm
post #1070 of 9622

I need to go back and understand why my instructions say that no tone should be coming from the sub.  Not to worry, whether the sub is outputting a signal or not should have no effect on the mic calibration.

 

Let's ignore the error you received for now.  The measurements look OK.  BTW, I thought we had agreed to display full frequency sweeps with 1/6 smoothing, and bass frequency sweeps with no smoothing.  Can you re-post the measurements with 1/6 smoothing?

post #1071 of 9622

Wow, check out my sub only response (no smoothing) just by relocating it to the middle of the room as Sanjay suggested several posts ago!!  No Audyssey correction either (since my Audyssey calibration was done with the sub in the right corner):

 

 

Here's the mid front wall location vs. right corner with Audyssey:

 

 

 

 

 

Another big THANKS is in order to Sanjay for his recommendation!


Edited by jkasanic - 2/10/13 at 1:47pm
post #1072 of 9622

I noted in a previous post that the noise floor in my room was measuring 50dB with the UMM-6, when it had been measuring 40dB with the EMM-6.  I don't know why, but your experience is consistent with mine.  I don't think you RS SPL is bad--those things are indestructible.  I have had mine for at least 20 years.

post #1073 of 9622
Quote:
Originally Posted by AustinJerry View Post

I need to go back and understand why my instructions say that no tone should be coming from the sub.  Not to worry, whether the sub is outputting a signal or not should have no effect on the mic calibration.

 

Let's ignore the error you received for now.  The measurements look OK.  BTW, I thought we had agreed to display full frequency sweeps with 1/6 smoothing, and bass frequency sweeps with no smoothing.  Can you re-post the measurements with 1/6 smoothing?

 

Yes, I will edit my post above to show 1/6th.  I was a little confused because the guide was still referencing 1/24th so I figured I would err on the side of less smoothing.

post #1074 of 9622
Quote:
Originally Posted by jkasanic View Post

Wow, check out my sub only response (no smoothing) just by relocating it to the middle of the room as Sanjay suggested several posts ago!!  No Audyssey correction either (since my Audyssey calibration was done with the sub in the right corner):

 

 

Here's the mid room location vs. right corner with Audyssey:

 

 

 

 

 

Another big THANKS is in order to Sanjay for his recommendation!

 

Yes, that is an improvement.  And it shows the value of being able to measure!

post #1075 of 9622

Btw, for the sub mid-room placement, I am not seeing much of a difference between the with Audyssey and without Audyssey graphs.  Are you saying you have not re-calibrated with the sub mid-room?

post #1076 of 9622
Quote:
Originally Posted by jkasanic View Post

 

Yes, I will edit my post above to show 1/6th.  I was a little confused because the guide was still referencing 1/24th so I figured I would err on the side of less smoothing.

 

OK, I need to proof-read the guide again.  Suggestions have been coming in quite rapidly, and keeping the guide current is becoming a challenge.

post #1077 of 9622
Quote:
Originally Posted by AustinJerry View Post

Btw, for the sub mid-room placement, I am not seeing much of a difference between the with Audyssey and without Audyssey graphs.  Are you saying you have not re-calibrated with the sub mid-room?

 

Correct, I was just showing the Audyssey correction graph with sub in the front right corner vs. relocating the sub mid-room with no Audyssey correction.  As it has been stated numerous times in the Audyssey thread, giving Audyssey a better starting point can generally improve the results.  Once I'm able to "permanently" place the sub behind my screen (below center channel), I'll rerun Audyssey XT32 and compare again.  Unfortunately, I'm going to have to make some modifications to my center speaker stand to accommodate the new sub location.  This result was just from measuring with the sub in front of the false wall as Sanjay suggested.

post #1078 of 9622

Got it, now I recall.  But you are correct, a better starting point will result in a better calibration result.

post #1079 of 9622

Ok, here's another yousendit link to my mdat files for those interested in giving more detailed feedback.  As always, much appreciated!

post #1080 of 9622
Quote:
Originally Posted by jkasanic View Post

@AJ:  Make sure you read my edits above.  No HDMI cable and some weird behavior with my mic thus far.

Ok, here's L+R+Sub with and without Audyssey:







I'm still not sure I did the SPL calibration correctly.  I did uncheck "Control Input Mixer Volume" but I didn't do another SPL calibration.  Judging by where my measurements are centered...I'm guessing I need to?

EDIT:  Quiet room measurements are like 55 dB.  I was closer to 45 with my OM mic?  I'm wondering if my Ratshack 33-2055 SPL is suspect?!

Hi jkasanic, I'll wait for others to chime in to tell how much meaningful it is to take L+R+Sub measurements or not.

In the meantime, allow me to put a general note here that I'm sure many of us are are aware of.

If these were graphs taken at a single point (suppose at MLP), neither the without Audyssey nor the with Audyssey will ever give you a clear picture on what is going on in your room. The whole principle of acoustical measurements, as we know very well, is based on not just multiple measurements, but on a final averaging of them. Well, even though REW allows the averaging of several measurements by clicking on the button on the lower left side of the graph, it will still only be a rough estimate of what Audyssey is doing due to the case that all measurements will be taken into account with the same importance. The "secret sauce" of Audyssey differs, namely by weighing the different curves and applying fuzzy logic to draw the final curve done with the aid of a pattern recognition routine where similar problems are taken into account with higher importance than the ones that show up with less probability.

I just wanted to share this detail of difference between REW and Audyssey as a reminder of "stuff" many already know. smile.gif
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