or Connect
AVS › AVS Forum › Audio › Audio theory, Setup and Chat › Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs
New Posts  All Forums:Forum Nav:

Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How... - Page 42

post #1231 of 9570
Quote:
Originally Posted by baniels View Post

Nice. Bigger case than the EMM-6. Say, what is that white and silver thing in the middle?

Mailman is bringing mine today.
Quote:
Originally Posted by kbarnes701 View Post

Tada!!!!!

The USB stick with the cal files on it.

Gear mentioned in this thread:

post #1232 of 9570
Quote:
Originally Posted by Alan P View Post

Quote:
Originally Posted by amirm View Post

Seems like you are performing a sweep (i.e. with the tones playing). Don't do that. Run it with no signal. Just click on the RTA button and then the red "record" button on top right in a quiet room and you should see the spikes.

FYI I received a nice acknowledgement from Dayton that they are aware of the problem and are looking into it.

Ahhh, got it, thanks.

 

Oh great. I waited over 2 weeks for the mic to come from the States, paying about 45 dollars carriage and 40 dollars Customs and now it might be faulty???

post #1233 of 9570
Quote:
Originally Posted by jkasanic View Post

Another option might be a UPC/APS battery backup.

Really, the small 60hz hum isn't even visible on the waterfall (with the limits I used), is it something I really need to worry about a lot?
post #1234 of 9570
Quote:
Originally Posted by kbarnes701 View Post

Well, I've just spent a fruitless hour. I set it all up as per the guide with the UMM-6. Everything checks out in Windows and in REW. I calibrated the mic to 85dB using two different SPL meters (reading within 1dB of each other) and set the 85dB in the REW SPL calibration box etc. When I run the first measurement I get a warning saying the level is too low and the max reading it will be able to take is 92dB or so - the headroom figure in the RE pane is 43.3dB, way too low. The AVR volume is at -10dB. Something is clearly wrong and I cannot get past this step.

 

Any suggestions?  Never had any problem like this when using my OmniMic mic during initial testing. 

 

What is the level of the UMM-6 Mic set to in Windows?  The guide was recommending 60 to start but I also had issues and set it to 100 to avoid a similar issue.  See this post to see if it is similar to your issue.

post #1235 of 9570
Quote:
Originally Posted by kbarnes701 View Post

Quote:
Originally Posted by Alan P View Post

Quote:
Originally Posted by amirm View Post

Seems like you are performing a sweep (i.e. with the tones playing). Don't do that. Run it with no signal. Just click on the RTA button and then the red "record" button on top right in a quiet room and you should see the spikes.

FYI I received a nice acknowledgement from Dayton that they are aware of the problem and are looking into it.

Ahhh, got it, thanks.

 

Oh great. I waited over 2 weeks for the mic to come from the States, paying about 45 dollars carriage and 40 dollars Customs and now it might be faulty???

 

D*mn early adopters...I thought I had enough of this with my media streamer! tongue.gif

post #1236 of 9570
Quote:
Originally Posted by AustinJerry View Post

There are also a couple of rubber O-rings that need to be removed for the mic to slide all the way down. Don't know what they are for.

 

Well, I like the way Keith snaps the holder onto the mic, rather than removing the O-rings and sliding it on.  I guess the O-rings are to keep it from sliding off.  Learned something today, thanks.

post #1237 of 9570
Ah-ha, found the spikes in a full sweep I did on my subs only.

post #1238 of 9570
Maybe one O-ring above and one below the clip, both snugged up to it, so that vibration won't make the mic move up or down in the holder?
post #1239 of 9570
Quote:
Originally Posted by Alan P View Post

Ah-ha, found the spikes in a full sweep I did on my subs only.


At 75 decibels how could that not interfere with proper measurements? Now I'm a bit concerned. I really need to run some tests, but I've just been too busy to do it.
post #1240 of 9570
Quote:
Originally Posted by kbarnes701 View Post

Well, I've just spent a fruitless hour. I set it all up as per the guide with the UMM-6. Everything checks out in Windows and in REW. I calibrated the mic to 85dB using two different SPL meters (reading within 1dB of each other) and set the 85dB in the REW SPL calibration box etc. When I run the first measurement I get a warning saying the level is too low and the max reading it will be able to take is 92dB or so - the headroom figure in the RE pane is 43.3dB, way too low. The AVR volume is at -10dB. Something is clearly wrong and I cannot get past this step.

 

Any suggestions?  Never had any problem like this when using my OmniMic mic during initial testing. 

 

Let's see if we can get to the bottom of this, Keith.  First of all, please confirm that the mic level in Windows Audio is set to 100%.

 

Next, open the REW SPL tab.  Set your AVR MV to -10.  With the mic plugged in, click Calibrate, use the subwoofer calibration signal, enter 85 in the SPL Reading, and click finished.  What is the value on the headroom pop-up?

 

 

It should read somewhere in the 95-120 range.  Does it?

 

Assuming you pass this test, and with the REW SPL still open, click Calibrate again, use the subwoofer tone again, and drag the "SPL Reading Calibration" screen out of the way so you can see the reading being displayed on the SPL.  It should be fluctuating around 85dB, assuming everything is working OK.  Is it reading 85db?  If yes, then REW is receiving a proper signal from the mic.

 

Now click on the Measure icon.  Is everything set up as follows?

 

 

Now click "Start Measuring".  This screen is displayed:

 

 

Looking at the level indicators on the right, are you seeing green bars in both the In and Out meters?  What is the headroom that is displayed?

 

Looking forward to your answers.

 

Edit:  With the REW SPL open, click the red record button when no tone is being generated.  Whta level is being displayed, i.e. what is the noise floor?

post #1241 of 9570

You know, I think it's worth mentioning that Mr. Barnes could've gotten a head start on these (Windows) setup issues with his OM mic...just sayin'! biggrin.gif


Edited by jkasanic - 2/13/13 at 11:42am
post #1242 of 9570

Just because I was feeling a little left out of the spikes issue, I checked my measurements and what do you know...

 

post #1243 of 9570

Here is what the RTA is showing for my mic:

 

 

The spike at 1kHz is 40dB, and subsequent spikes are at a lower level.  If we smooth the frequency response measurements, won't these spikes become insignificant?  While I agree they shouldn't be there, I'm not convinced they are adversely affecting our measurements.  Perhaps someone with a deeper understanding can explain how they are affecting the measurement results.

post #1244 of 9570
They will be affecting the measurements if you are receiving them at 75dB & measuring at 75dB. They will become part of the "collected" data at that point.
post #1245 of 9570

^ Here is a measurement I took of my system yesterday (no smoothing):

 

 

With all the normal "whiskers" above 1kHz, how can the noise from the mic (very narrow spikes at 1kHz intervals) significantly affect the measurement?  Can you see the effect?

 

And same measurement at 1/6 smoothing:

 

 

Where is the effect?

post #1246 of 9570

^^^^ Makes sense to me that if we're smoothing the data then these narrow peaks will not be "visible" or even measurable in our graphs but I'm the rookie...

post #1247 of 9570
Quote:
Originally Posted by AustinJerry View Post

Quote:
Originally Posted by kbarnes701 View Post

Well, I've just spent a fruitless hour. I set it all up as per the guide with the UMM-6. Everything checks out in Windows and in REW. I calibrated the mic to 85dB using two different SPL meters (reading within 1dB of each other) and set the 85dB in the REW SPL calibration box etc. When I run the first measurement I get a warning saying the level is too low and the max reading it will be able to take is 92dB or so - the headroom figure in the RE pane is 43.3dB, way too low. The AVR volume is at -10dB. Something is clearly wrong and I cannot get past this step.

 

Any suggestions?  Never had any problem like this when using my OmniMic mic during initial testing. 

 

Let's see if we can get to the bottom of this, Keith.  First of all, please confirm that the mic level in Windows Audio is set to 100%.

 

Next, open the REW SPL tab.  Set your AVR MV to -10.  With the mic plugged in, click Calibrate, use the subwoofer calibration signal, enter 85 in the SPL Reading, and click finished.  What is the value on the headroom pop-up?

 

 

It should read somewhere in the 95-120 range.  Does it?

 

Assuming you pass this test, and with the REW SPL still open, click Calibrate again, use the subwoofer tone again, and drag the "SPL Reading Calibration" screen out of the way so you can see the reading being displayed on the SPL.  It should be fluctuating around 85dB, assuming everything is working OK.  Is it reading 85db?  If yes, then REW is receiving a proper signal from the mic.

 

Now click on the Measure icon.  Is everything set up as follows?

 

 

Now click "Start Measuring".  This screen is displayed:

 

 

Looking at the level indicators on the right, are you seeing green bars in both the In and Out meters?  What is the headroom that is displayed?

 

Looking forward to your answers.

 

Edit:  With the REW SPL open, click the red record button when no tone is being generated.  Whta level is being displayed, i.e. what is the noise floor?

 

Jerry - thank you SO much for the time you took on this reply - and I apologise SO much for wasting it!  Like a total dummy, I was sure I had set the levels correctly in Windows - in fact I remember doing so - but it seems I did not save them both - one was at the correct 100dB and the other was at...... 6dB (its default apparently). Of course, being so sure I had done it all properly this was the LAST thing I checked. In exasperation I went all through it all again and there it was.... 6 ****ing dB. I reset it to 100dB and all is well. 

 

I have had enough fiddling for now and am about to feed myself and my dog (Mrs Keith has been found in fine restaurants everywhere this evening, pre-theatre). I shall come back to it tomorrow and make some proper measurements. Thanks again for the troubleshooting.

 

I will delete my earlier post in case anyone else feels inclined to respond.

post #1248 of 9570
Just got my minidsp umik1 and it is showing the same 1khz and harmonics spikes. Haven't had a chance to compare it to my CSL calibrated EMM6 yet. Will probably be sending it to CSL for a full calibration report before I do much testing.



-Mike
post #1249 of 9570
Quote:
Originally Posted by jkasanic View Post

Quote:
Originally Posted by kbarnes701 View Post

Well, I've just spent a fruitless hour. I set it all up as per the guide with the UMM-6. Everything checks out in Windows and in REW. I calibrated the mic to 85dB using two different SPL meters (reading within 1dB of each other) and set the 85dB in the REW SPL calibration box etc. When I run the first measurement I get a warning saying the level is too low and the max reading it will be able to take is 92dB or so - the headroom figure in the RE pane is 43.3dB, way too low. The AVR volume is at -10dB. Something is clearly wrong and I cannot get past this step.

 

Any suggestions?  Never had any problem like this when using my OmniMic mic during initial testing. 

 

What is the level of the UMM-6 Mic set to in Windows?  The guide was recommending 60 to start but I also had issues and set it to 100 to avoid a similar issue.  See this post to see if it is similar to your issue.

 

Spot on - see my reply to Jerry.

post #1250 of 9570
Quote:
Originally Posted by jkasanic View Post

You know, I think it's worth mentioning that Mr. Barnes could've gotten a head start on these (Windows) setup issues with his OM mic...just sayin'! biggrin.gif

 

I did - no problems at all with the OM mic - but to be cautious I went back into Windows and did all the settings again before using the new mic. And that, folks, is where I went wrong :)

post #1251 of 9570
Quote:
Originally Posted by jkasanic View Post

Another option might be a UPC/APS battery backup.

I figure that anybody who's commenting on something I've commented on is like me, long forgotten. tongue.gif

Did you try connecting the PC into a power cord that connects to the same supply as the AVR? Next time I connect things, that's what I'll be doing so I have the same main service based breaker ground being used. If I haven't already, good luck. wink.gif
post #1252 of 9570
Quote:
Originally Posted by AustinJerry View Post

 

Edit:  With the REW SPL open, click the red record button when no tone is being generated.  Whta level is being displayed, i.e. what is the noise floor?

 

Jerry - I am reading a noise floor of about 50dB. It is, in reality, about 40dB. Same issue as everyone (if it is an issue).

post #1253 of 9570
Quote:
Originally Posted by ironhead1230 View Post

Just got my minidsp umik1 and it is showing the same 1khz and harmonics spikes. Haven't had a chance to compare it to my CSL calibrated EMM6 yet. Will probably be sending it to CSL for a full calibration report before I do much testing.



-Mike

Interesting - so it might not be the UMM-6 after all then, if your UMIK-1 is showing the same thing. Unless they both have the same issue, which would be unusual.

post #1254 of 9570
You could try experimenting with the sub distance in the AVR settings. Just do sweep after sweep, naming each measurement with the sub's distance setting. See if you can get that to go away.
Quote:
Originally Posted by Alan P View Post


Subs + L/R, Audyssey ON/OFF overlayed:



On the full range sweeps, Audyssey created a big dip between 90-170hz. This is the "meat" of the mid-bass, correct?

/quote]
post #1255 of 9570
Quote:
Originally Posted by jkasanic View Post

Quote:
Originally Posted by AustinJerry View Post

Quote:
Originally Posted by jkasanic View Post

 

Thanks for the feedback!  So far, I haven't been reluctant to measure anything!  I just didn't post the L+R (and L+R+Sub) graph.  Check out the legends in my graphs and you'll see I've got all the data!

 

I'll post the comparison of measurements 8 and 16 (L+R+Sub before and after) tomorrow since I just shutdown the laptop for the evening.

 

 

Can you upload the measurement file as well?

 

Ok, here are the graphs you requested:

 

L+R 1/6th smoothing before and after the change to 42" from sidewall for L and R:

 

 

Here's the same plus sub (in right corner location):

 

 

That null at 111 Hz is interesting...will need to see how Audyssey does once I get the sub relocated.  Also, I should reiterate that everything is crossing at 90Hz currently.  I'd be interested to learn more about selecting a different crossover based on the interaction of the mains with the sub?  I'm still curious why Audyssey chose 40Hz on my surrounds (even though the manufacturer specs rate them 40Hz-20kHz, I'd be surprised if they performed that well down there).

 

Finally, here's another Yousendit Link for the baseline measurements from yesterday as well as the measurements after the change to 42" for Left and Right.

 

@AJ:  Did you by chance happen to download my latest mdat files?  I was curious if you were able to make anything out of waterfall plots?  I've been playing around using the guide as a reference but I'm not sure which sets of measurments are the most meaningful (i.e. sub only, L+sub, R+sub, L+R+sub etc.) for generating waterfalls?  It's pretty clear that I have a major issue at 30 Hz (even with the sub relocated to the mid front wall):

 

Sub only current right front corner loaded location:

 

 

Here's the mid front wall location (which wasn't in the latest set of measurements so let me know if you're interested in the measurement file):

 

post #1256 of 9570
Quote:
Originally Posted by ironhead1230 View Post

Just got my minidsp umik1 and it is showing the same 1khz and harmonics spikes. Haven't had a chance to compare it to my CSL calibrated EMM6 yet. Will probably be sending it to CSL for a full calibration report before I do much testing.



-Mike

FWIW, my bet, the recording gains are too high. Things to check if using Windows would be, the microphone input on Windows. Right click your on screen speaker icon and then, while the microphone is connected, left click "Recording devices." Set the gain to between 1 and 4. Doing this should reduce the noise greatly. Also, to keep recording sensitivity up, I set the master control volume to -10 and this keeps recording levels up and doesn't introduce gain noise into the recording.

If using a Phantom Power Supply, check the input gain and if you can, lower it. Also, if you're able, connect a headphone set to the Phanton Power Supply so you can monitor the signal. As you turn the gain to the input microphone up, you should be able to hear the threshold where line level noise jumps, at which point, then turn it down a skunch. For our situation, that's about as good as it gets.

And ya gotta love how the EMM6 comes with it's very own, downloadable, microphone specific, calibration chart/graph.
post #1257 of 9570
Quote:
Originally Posted by kbarnes701 View Post

 

Jerry - I am reading a noise floor of about 50dB. It is, in reality, about 40dB. Same issue as everyone (if it is an issue).

 

Looks like you are OK now, Keith.  And the noise floor is consistent with what others are seeing.

 

@ Everyone, let's learn from Keith's experience.  I have seen the same thing happen many times on my laptop--a Windows Audio setting that I had set previously gets changed to a different value, thus affecting REW performance.  I use the same laptop for Audyssey Pro calibrations, and after running Pro, I have found the Windows Audio settings changed.

 

My advice:  Every time you are going to run a new REW session, check the Windows Audio settings before loading REW.  You want to have a consistent, known starting point.  Trust me--it is worth the extra minute or two of your time.

 

@Keith:  thanks for sharing your experience.  I couldn't have scripted it any better!

post #1258 of 9570
Quote:
Originally Posted by kbarnes701 View Post

Interesting - so it might not be the UMM-6 after all then, if your UMIK-1 is showing the same thing. Unless they both have the same issue, which would be unusual.

It may be the issue Amir posted about and all current USB mics might be affected.. If anyone has an Omnimic working with REW, I would be interested to see if it shows the same spikes.

-Mike
post #1259 of 9570
Quote:
Originally Posted by Alan P View Post

I can't stress enough the importance of experimenting with sub placement - especially if you have multiple and/or mis-matched subs. The inter-reaction between them is key to getting good sound. I'm stunned by how just moving one sub from the front to the back of the room made a world of difference.
Considering your "that just ain't happening" reply yesterday to my suggestion, I'm glad you changed your mind and tried it out. Did you put two of the same subs near your seating or two different subs?
post #1260 of 9570
Quote:
Originally Posted by BeeMan458 View Post

Quote:
Originally Posted by ironhead1230 View Post

Just got my minidsp umik1 and it is showing the same 1khz and harmonics spikes. Haven't had a chance to compare it to my CSL calibrated EMM6 yet. Will probably be sending it to CSL for a full calibration report before I do much testing.



-Mike

FWIW, my bet, the recording gains are too high. Things to check if using Windows would be, the microphone input on Windows. Right click your on screen speaker icon and then, while the microphone is connected, left click "Recording devices." Set the gain to between 1 and 4. Doing this should reduce the noise greatly. Also, to keep recording sensitivity up, I set the master control volume to -10 and this keeps recording levels up and doesn't introduce gain noise into the recording.
 

 

Have you actually tried your suggestion yourself?  This is exactly the problem I described in my earlier post with the warning that the levels are too low - I have deleted my post but it is quoted in Jerry's very helpful reply. My level was set at 6 and renders REW useless. It needs to be set at or about 100 as in the Guide.

New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Audio theory, Setup and Chat

Gear mentioned in this thread:

AVS › AVS Forum › Audio › Audio theory, Setup and Chat › Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs