Improving measurements with a new mic

2234rew

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There are two separate issues when talking measurement microphones. Was the mic properly calibrated? And if using a USB mic, potential timing issues.

I made a comparison a while back between analog and USB mic. And in the case of the USB mic, one with and without Audiolense's "clock drift correction" using my triamp system and Lynx Hilo.

Analog mic:
View attachment 47849
USB mic with clock drift correction:
View attachment 47850
USB mic without clock drift correction:
View attachment 47851

Bernt's clock drift correction works very well.

There are (very) small differences in the timing between the analog mic and USB with clock drift correction. There are also frequency response differences at the extremes between all three measurements.

The analog mic shows a perfect channel match in the low frequencies and natural rolloff in the top octave. Whereas the USB mic shows a bit of low frequency mismatch between channels and a bit of a rising top end. Now whether any of that is audible...

Of course, the USB mic measurement without clock drift correction is unusable timing wise.

While the USB mic is "convenient" I sold mine and stuck with the isecmcon analog mic.

Thanks mitch

I definitely has clock drift correct enabled with UMIK-2

The measurements on the screen looked fine (step response)

It was music playback that sounded very off. Vocals that should be dead centre were heard left and right , from the speakers

I use Harry Belafonte "Dayo" live at Carnegie Hall as my centre vocal test.

With 2 different UMIK-2's it sounded so wrong in 2 different systems. After multiple days trouble shooting and repeating test in slightly different measurement positions.

M23 on first try nailed it. All done in 15 minutes
 

2234rew

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And I forgot to mention something really important - with my M23 I am using the small Focusurite Scarlett Solo Gen3 for ADC.

So I am using USB clock drift with M23 + Focusrite ADC , just like with UMIK-2

I had same "vocals coming from left and right speakers, not center" with 2 different UMIK-2s, in 2 different systems.

My system is very humble but the other is a $100k Magico system in a dedicated $50k room seperate to his house. Seperate building really, not just seperate room. He hardly even needs room correction based on REW measurements.

And even in that room, I ran Audiolense XO with UMIK-2 measurements, multiple times, slightly different positions (moving an inch or so each time) , 2 different UMIK-2s and each time I went to load my playlist on Qobuz for testing, track 1 is The Harry Belafonte song and every time, vocals were coming from left and right speaker.

Turn correction off, and vocals are dead center.

Run measurement and correction with M23 - vocals dead center first time.

UMIK-2 really drove me nuts for multiple weekends.

I suspect the forum comments I've seen around, that UMIK-2 is better for speaker correction than room correction (smaller capsule than UMIK-1) may have something true.

@dsnyder0cnn if Harry's vocals during verse of Dayo, Banana Boat Song (Live from Carnegie Hall version !) is dead center, then you're UMIK-2 from Cross Spectrum Labs is great and no need to change.

If vocals during verse is left+right , time to get M23 or @Mitchco's recommended isecmcon
 
Last edited:

dsnyder0cnn

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And I forgot to mention something really important - with my M23 I am using the small Focusurite Scarlett Solo Gen3 for ADC.

@dsnyder0cnn if Harry's vocals during verse of Dayo, Banana Boat Song (Live from Carnegie Hall version !) is dead center, then you're UMIK-2 from Cross Spectrum Labs is great and no need to change.

If vocals during verse is left+right , time to get M23 or @Mitchco's recommended isecmcon
Your setup sounds similar to mine (but much nicer mic), I I'm using a Focusrite Scarlett 2i2 gen2 with my Cross•Spectrum Labs EMM-6.

I finally had some time to take measurements with both mics this evening. Here's what I'm seeing in the amplitude domain (SPL) with psychoacoustic smoothing:

47852


47853


I'm satisfied with his match, especially since my EMM-6 is 5+ years older than the UMIK-2. Distortion levels were significantly lower with the UMIK-2 sweeps:

47854


In the time-domain, there are some differences. I'm using a Gustard X16 DAC (L-FAST filter) to play the sweeps that I recorded with the UMIK-2. I used REW's Acoustic Timing Reference for both, but alignment was not perfect…the start is off by about 590 us with visible differences in group delay over the first 20 ms.

47855


47856


Scaling out to almost 120ms, the amount of drift seems to increase (note the difference in scale). The UMIK-2 starts out 590 us ahead but ends up falling behind as time progresses:

47857


47858


I mean, they are not radically different. I did my best to place both mics in exactly the same location, but the differences could be, at least in part, due to less than perfect mic placement consistency.

I've not attempted to record any sweeps using the UMIK-2 in Acourate. I've heard that it's possible, but I'm not interested in messing around with ASIO4ALL or other nonsense. Now that I see that my two Cross•Spectrum Labs mics agree within reasonable margin of error, I'll stick with @Mitchco 's advice. It's the EMM-6 + Focusrite for sweeps that I use for building filters and the UMIK-2 for analysis and verification.
 

2234rew

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Your setup sounds similar to mine (but much nicer mic), I I'm using a Focusrite Scarlett 2i2 gen2 with my Cross•Spectrum Labs EMM-6.

I finally had some time to take measurements with both mics this evening. Here's what I'm seeing in the amplitude domain (SPL) with psychoacoustic smoothing:

View attachment 47852

View attachment 47853

I'm satisfied with his match, especially since my EMM-6 is 5+ years older than the UMIK-2. Distortion levels were significantly lower with the UMIK-2 sweeps:

View attachment 47854

In the time-domain, there are some differences. I'm using a Gustard X16 DAC (L-FAST filter) to play the sweeps that I recorded with the UMIK-2. I used REW's Acoustic Timing Reference for both, but alignment was not perfect…the start is off by about 590 us with visible differences in group delay over the first 20 ms.

View attachment 47855

View attachment 47856

Scaling out to almost 120ms, the amount of drift seems to increase (note the difference in scale). The UMIK-2 starts out 590 us ahead but ends up falling behind as time progresses:

View attachment 47857

View attachment 47858

I mean, they are not radically different. I did my best to place both mics in exactly the same location, but the differences could be, at least in part, due to less than perfect mic placement consistency.

I've not attempted to record any sweeps using the UMIK-2 in Acourate. I've heard that it's possible, but I'm not interested in messing around with ASIO4ALL or other nonsense. Now that I see that my two Cross•Spectrum Labs mics agree within reasonable margin of error, I'll stick with @Mitchco 's advice. It's the EMM-6 + Focusrite for sweeps that I use for building filters and the UMIK-2 for analysis and verification.

Thanks for sharing.

As noted, nothing looked out of place in my simulations with Audiolense XO

I have to admit I didn't do verification measurements with REW with the UMIK-2

The AL XO simulations looked good. It was the listening that sounded horrible - as mentioned, the vocal was coming from left and right speaker, instead of dead center.

It's possible that REW verification measurements and phase plots would show a problem with my UMIK-2 (maybe, maybe not) but I have trusted AL XO simulations.

Everything sounded correct with my M23 + Focusrite Solo Gen3 (on first attempt) so UMIK-2s were sent packin :-)

With M23 I have done REW verification measurements and been very happy. It's just that I didn't do any with the UMIK-2s . They caused me too much lost time and heartache. I was happy to send them away

How do the 2 mic measurements actually sound @dsnyder0cnn ? Playing the live track I mentioned, they both sound the same? With the same correction? Vocals center?
 

dsnyder0cnn

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Thanks for sharing.

As noted, nothing looked out of place in my simulations with Audiolense XO

I have to admit I didn't do verification measurements with REW with the UMIK-2

The AL XO simulations looked good. It was the listening that sounded horrible - as mentioned, the vocal was coming from left and right speaker, instead of dead center.

It's possible that REW verification measurements and phase plots would show a problem with my UMIK-2 (maybe, maybe not) but I have trusted AL XO simulations.

Everything sounded correct with my M23 + Focusrite Solo Gen3 (on first attempt) so UMIK-2s were sent packin :-)

With M23 I have done REW verification measurements and been very happy. It's just that I didn't do any with the UMIK-2s . They caused me too much lost time and heartache. I was happy to send them away

How do the 2 mic measurements actually sound @dsnyder0cnn ? Playing the live track I mentioned, they both sound the same? With the same correction? Vocals center?

As you've found, the quality of the final results depends on not just your filter design work but also the quality of the recorded sweeps. That's why I always do end-to-end measurements in REW to verify the results. I'm a Roon subscriber, so for me, that means playing pre-recorded left and right sweep files in Roon using the same DAC that I use for playing music and measuring the output using REW and my best mic, which now it seems is the UMIK-2.

I've not attempted to build filters using measurements from the UMIK-2. If I decide to give it a go, I'll probably just import the measurements I took using REW into Acourate rather than attempting to record in Acourate due to lack of ASIO drivers. Thanks for sharing your reference track for testing. I'll let you know if vocals fail to be centered with either one. :)

I'll test with this track: https://tidal.com/browse/track/25807180
 

2234rew

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Thanks for sharing your reference track for testing. I'll let you know if vocals fail to be centered with either one. :)

I'll test with this track: https://tidal.com/browse/track/25807180

Thanks, this is the correct Tidal album link (Track 7):


Whenever I do room correction now, this is the first thing I listen to, to make sure vocal is centre.

If that is wrong to start with (vocals coming from the left and right speakers separately) I don't both listening anymore. Back to the drawing board. Luckily haven't had that issue since getting M23.

47874
 

yoav

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Hello

Does the earthworks m23 come with a 90-degree calibration file so it can be used with Dirac live to measure H.T room ?


Thank you
 

whoareyou

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Hello,

Currently I´m using the Umik-1 USB mic to do the measurements in Audiolense. I´m wondering if a mic like the Earthworks M23 or the Audix TM-1 will be better for that (mostly time alignment). My DAC is the Okto dac8 PRO, it has a micrphone input (AES/EBU) but doesn´t provide phantom power.

Thank you
AFIK this DAC does not support microphone input. Was there a firmware update to enable this?
 

jrobbins50

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For what it is worth, I have both UMIK-1 and UMIK-2 USB mics and an Okto dac8pro, which requires use of only a USB mic. Lots of clock inconsistencies and, most recently, I’ve discovered that even with auto polarity on in AL XO, my filters cause my main speakers to be out of phase.

I’m switching to an isemcom mic at Mitch’s suggestion with a used Motu 828mk3 to do my measuring. One clock should solve my issues, thinks Mitch. Maybe same for you, Fon. JCR
 

juicehifi

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The problems reported with Umik2 here sounds like glitches in the digital stream. The clock synchonisation makes thing worse if there are glitches in the data stream, since it messes up the relative timing on various frequencies as well as between speakers.
 

whoareyou

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For what it is worth, I have both UMIK-1 and UMIK-2 USB mics and an Okto dac8pro, which requires use of only a USB mic. Lots of clock inconsistencies and, most recently, I’ve discovered that even with auto polarity on in AL XO, my filters cause my main speakers to be out of phase.

I’m switching to an isemcom mic at Mitch’s suggestion with a used Motu 828mk3 to do my measuring. One clock should solve my issues, thinks Mitch. Maybe same for you, Fon. JCR
FWIW - I've now taken many measurements with my Isemcon mic and motu ultra mk-5 combination, and it's like night and day compared with my previous UMIK-1 measurements. Every measurement, as long as Mic is left in same postion, is now effortless and the timings between each measurement shows the same exact timings. With UMIK-1, I now realize, the timings always moved around.
 
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Every measurement, as long as Mic is left in same postion, is now effortless and the timings between each measurement shows the same exact timings.


I have exactly the same measuring setup. Have you tried increasing recording time? If I go from 5 to 10 seconds, the time delay of the drivers changes
 

whoareyou

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I have exactly the same measuring setup. Have you tried increasing recording time? If I go from 5 to 10 seconds, the time delay of the drivers changes
Next time I measure I can try this, but it might not be for a while. Never saw the need for a signal greater than 5 seconds, so never tried it. My system is 5.2 passive and very consistent. I've even added room treatments between measurements, and can see the impact with the new measurements. Switch the treatments back, and everything goes back to the original measurements before treatments are moved. It's pretty nice for me.

So when you use a 5 second signal, the time delays stay consistent (as expected) for each measurement? And when you switch to a 10 second signal, timings unexpectedly change with each measurement?

How many channels do you measure i.e. do you have subwoofer?
 
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I took a screenshot from another computer with Al, this makes it look like I measured with Asio4All, but it was with a Motu and their asio drivers.
As you can see, the difference is not earth-shattering, but it is present and repeatable. The step response was also slightly better at 10 seconds.
These are three-way speakers supplemented with 2 subwoofers.

2024-01-13 (1).png
2024-01-13.png
 

whoareyou

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I could be wrong, but I seem to remember from some other thread, and from those much more knowledgeable, that a difference of of 1 hundreths is within tolerance.

Acceptable Tolerance

For comparison, when I measured with UMIK1 I'd have differences iof .2 millisecond and sometimes much larger. I would have been thrilled to consistently have a difference of 1 hundreths Also, when listening to some of the generated filters, it was very obvious something was wrong i.e. image pulled to a side.

Also, your system is very different from mine as you are building your own speaker xovers. I've never measured such system, so perhaps it's common to experience these "hundreths" differences.
 
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The difference will be within tolerance, as you noted.
In any case, the difference between the Motu and measuring with 2 different devices is a fact. Measurements longer than 5 seconds were not possible anyway.
 

whoareyou

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So, next time I measure, I'll let you know how 10seconds works out, but it won't be for a while.

I'm not sure I understand your comment about the "10 seconds were not possible". Wasn't the 1st measurement, which is configured at 10 seconds successful? . Do you mean that you can't repeat the same timing results when configured at 10 seconds? Sorry, not sure I follow

Also, when you are having issues, have you double checked the advanced options on measurement screen to make sure everything is configured correctly i.e clock drift correction disabled? That's gotten me a couple of times.
 
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Before I had theMotu, I used a Focusrite Scarlett 2i2 for recording and the OktoDAC8 for playback. With measurements of more than 5 seconds, things usually started to stutter or loud clicks sounded, making the measurement unreliable. Measurements of 5 seconds were not affected by this, but the timing was not particularly consistent.
 

whoareyou

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Before I had theMotu, I used a Focusrite Scarlett 2i2 for recording and the OktoDAC8 for playback. With measurements of more than 5 seconds, things usually started to stutter or loud clicks sounded, making the measurement unreliable. Measurements of 5 seconds were not affected by this, but the timing was not particularly consistent.
So you were using two different devices for measurement? Sorry, I misread all of this, as I thought you were talking about using the motu together with the Isemcon microphone when you were mentioning 5 or 10 seconds calibration tones.

With two different devices, the UMIK-1 and my exasound DAC, I'd have the loud clicks all the time, even with 5 second measurments.
And even if I didn't have clicks, the timings would still be off. That's why I switched to the Motu/Isemcon single clock solution.
 

NMixes

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Hello

Does the earthworks m23 come with a 90-degree calibration file so it can be used with Dirac live to measure H.T room ?


Thank you

No, they don't.

My M30 came without a 90° file and when I emailed them about it Earthworks said they don't measure and provide 90° files
 

yoav

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No, they don't.

My M30 came without a 90° file and when I emailed them about it Earthworks said they don't measure and provide 90° files
Well, I email them and that was there answer:

"As for 90-degree files — we do not capture 90-degree ECFs (Electronic Calibration Files) for each microphone, but the attached frequency plot and ECF indicate the 90 degree response of a typical Earthworks M-Series measurement microphone."

I decided to go for the M23 and to use the attached typical 90 degree measurement
 

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NMixes

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Hi DanDan, yes, I have been using isemcon mics for 10 years. Good company and mics. The DPA 4060's are very nice for sure. I have not seen the M2230 before, good specs!

Hello Mitch! Does isemcon mics provide an individual 90° calibration file?
 

Mitchco

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@NMixes Jeffrey has you covered and congrats! It is a nice mic and one of the very few that publishes it's distortion profile.

@yoav yes, this is the same answer and calibration file I also received a while back. Sorry I did not post it time when you asked your question.
 
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