miniDSP Umik-1 USB measurement microphone real world performance review

[stoneeh]

Hello audio enthusiasts.

As we all know, acoustic measurements can be extremely beneficial in designing and/or evaluating loudspeakers. As far as budget hardware is concerned, the miniDSP Umik-1 is a popular choice.

The Umik-1 comes with SPL & frequency calibration. However, it doesn't fulfill any standards, and since there also aren't any reviews in which its performance / accuracy has been tested, it basically has been up to guesswork if this piece of hardware provides reliable data.

To try to bring some light into the darkness for (potential) Umik-1 users, here's my comparison vs. reference (IEC 61672 Class 1) measurement hardware. I tried to keep it straight to the point - enjoy:

Regards
Stoneeh

 

[Matias]

Yay, my UMIK-1 is accurate enough.

Thanks for the effort in testing, documenting and sharing. Not all heroes wear capes.

 

[stoneeh]

Hello Matias.

Thank you for the kind words. In true scientific spirit, I can however only vouch for the fact that the one Umik-1 that I had available measures very accurately. For a general statement, I'd rather like to have a larger number available for testing, to gain a good statistical average (and make sure there are no outliers). If someone at miniDSP wants to send me, like, let's say ten, I'd be open for that

Regards
Stoneeh

 

[Katji]

The bottom line is that the UMIK is readily available, it's not too expensive, it connects straight to USB and it works well enough for the application.

 

[ernestcarl]

Hello audio enthusiasts.

As we all know, acoustic measurements can be extremely beneficial in designing and/or evaluating loudspeakers. As far as budget hardware is concerned, the miniDSP Umik-1 is a popular choice.

The Umik-1 comes with SPL & frequency calibration. However, it doesn't fulfill any standards, and since there also aren't any reviews in which its performance / accuracy has been tested, it basically has been up to guesswork if this piece of hardware provides reliable data.

To try to bring some light into the darkness for (potential) Umik-1 users, here's my comparison vs. reference (IEC 61672 Class 1) measurement hardware. I tried to keep it straight to the point - enjoy:

Regards
Stoneeh

Thanks... that was interesting. My own in-room (close/nearfield) UMIK-1 tests showed some odd behavior above 110 dB SPL so I simply lower the gain when measuring very close.

 

[MakeMineVinyl]

I did a comparison of a UMIK-1 to my much more expensive Bruel & Kjaer 1/2" instrumentation microphone for another thread, but it applies to this one also. The Bruel & Kjaer is in white and the UMIK-1 is in red, and as you can see, they effectively lay on top of each other. The Bruel & Kjaer starts to rise heavily in the higher frequencies since it is at 0 degrees incidence but it should be at 90 degrees to have a flat top end. I used 0 degrees because the UMIK-1 (which used its calibration file) was also at 0 degrees. The response is of my main left channel speaker at the listening position 11' away, without the subwoofers.

 

[McFly]

For what its worth I had a dayton EMM-6 that (with its dayton provided calibration file) measured like s*** compared to my Umik-1. Needed the passive mic for speaker design. Ended up with the soundworks xref20. Still measured a higher top end than the umik but nowhere near as wild as the EMM-6 measured.

I suspect the issue is more the factory calibration files, not so much the mic.

 

[stoneeh]

Thanks... that was interesting. My own in-room (close/nearfield) UMIK-1 tests showed some odd behavior above 110 dB SPL so I simply lower the gain when measuring very close.

Cheers.

Did you have the Windows volume at maximum? Because I noticed that on the default microphone gain, which is 18 dB for mine (I believe there were different versions with different default gains), the limiting factor as far as SPL is concerned wasn't overdriving the mic, but overdriving the input (dynamic range of the digital audio format). This was helped by lowering the Windows volume somewhat (I used around 50), and with that I was able to measure up to ~120 dB SPL without compression or added harmonic distortion. Above that, problems did occur, and I'd have to indeed lower the gain on the mic to measure accurately.

Interestingly, I also noticed the Windows volume setting for the Umic has no influence on the Umik's SPL calibration in REW, which per se doesn't make sense.. but somehow, obviously, REW compensates for it.

I did a comparison of a UMIK-1 to my much more expensive Bruel & Kjaer 1/2" instrumentation microphone for another thread, (removed full quote for brevity)

Interesting. One question: was this also an SPL calibrated measurement for both sets of hardware, or were the curves just manually scaled to match? If the former, how was the B&K calibrated?

For documentation, the NTI XL2 with M2230 I used was (to my knowledge - rental hardware) factory calibrated, and the EMX-7150 was hand-calibrated with the SC-1 (Class 2; +/- 0,5 dB).

 

[MakeMineVinyl]

Interesting. One question: was this also an SPL calibrated measurement for both sets of hardware, or were the curves just manually scaled to match? If the former, how was the B&K calibrated?

The Bruel & Kjaer microphone has no calibration file, and the curves were shifted manually. It doesn't need one for frequency response since it's flat natively and can be considered a standard.

 

[stoneeh]

Okay. Was just asking because if yes, we'd have a second confirmation of accurate SPL calibration for the Umik - as I alluded to in post #3, I can only vouch for the one Umik I measured - although I very much suspect that the results will be uniformal.

 

[MakeMineVinyl]

Okay. Was just asking because if yes, we'd have a second confirmation of accurate SPL calibration for the Umik - as I alluded to in post #3, I can only vouch for the one Umik I measured - although I very much suspect that the results will be uniformal.

I see no reason why the SPL calibration of the UMIK-1 would be off by any degree. If you can get your hands on a calibrator used for SPL meters, you might be able to test that.

 

[morpheusX]

I recently compared a CSL calibrated UMIK-1 (0º file) with a Stock Behringer ECM8000 + Behringer UMC404HD, and was amazed how well they tracked. Given the inconsistencies on the stock Behringer's, i suppose i was lucky

 

[ernestcarl]

Did you have the Windows volume at maximum? Because I noticed that on the default microphone gain, which is 18 dB for mine (I believe there were different versions with different default gains), the limiting factor as far as SPL is concerned wasn't overdriving the mic, but overdriving the input (dynamic range of the digital audio format). This was helped by lowering the Windows volume somewhat (I used around 50), and with that I was able to measure up to ~120 dB SPL without compression or added harmonic distortion. Above that, problems did occur, and I'd have to indeed lower the gain on the mic to measure accurately.

Interestingly, I also noticed the Windows volume setting for the Umic has no influence on the Umik's SPL calibration in REW, which per se doesn't make sense.. but somehow, obviously, REW compensates for it.

Hmmmn... I normally bypass the Windows volume and use the max input volume gain control inside REW's settings.

It's been a while so I'm sure I may have gotten the actual levels wrong -- but I try to keep the mic's input peak level or headroom under 10 dBFS.

I don't remember measuring up to 120 dB at all... maybe +115 max before headroom runs out and clipping occurs. I'll have to recheck, though.

 

[JimWeir]

The Bruel & Kjaer microphone has no calibration file, and the curves were shifted manually. It doesn't need one for frequency response since it's flat natively and can be considered a standard.

Ok. I’ll chime in here as a Bruel & Kjaer Technical specialist. Ask away. We do make many great reference microphones and sound level meters that are even more “flat” as we use DSP FIR EQ to optimize response. For instance our 4966 1/2 inch free field mic 0° axis is really flat out to 12kHz and take a little .7dB bump out to 19kHz.
When used on our $2500 type 2245 SLM we get rid of the bump - though the body of the SLM gives us a very slight 0.25 dB ripple.
Ask question about the world’s reference microphones. Or maybe I’ll start a new topic.

 

[SDC]

Two calibration and difference calculated.
Red is umik1(old ver with 5pin) factory.
Brown is custom made with m30.
(AFAIK, that m30 and audio interface were all calibrated by professionals as a single set)

Edit:

Compared with Behringer, 3years ago. very similar.

But I don't recommend Behringer if you don't have a reference.
Calibrated umik-1 will fulfill as reference and class1/2 requirement like shown above by everybody.

 

[Blumlein 88]

Ok. I’ll chime in here as a Bruel & Kjaer Technical specialist. Ask away. We do make many great reference microphones and sound level meters that are even more “flat” as we use DSP FIR EQ to optimize response. For instance our 4966 1/2 inch free field mic 0° axis is really flat out to 12kHz and take a little .7dB bump out to 19kHz.
When used on our $2500 type 2245 SLM we get rid of the bump - though the body of the SLM gives us a very slight 0.25 dB ripple.
Ask question about the world’s reference microphones. Or maybe I’ll start a new topic.

Start a new topic would be nice. Might want to view this thread if you haven't seen it. You might have some good input for us.

Measurement Microphones - what is the consensus?

Given this is a forum passionate about measurements, and seems to be more in favour of DSP and room correction methods than other pockets of the internet, I can't find a whole lot about measurement/calibration microphones. For the average home enthusiast looking to optimise their set-up...

www.audiosciencereview.com

 

[MakeMineVinyl]

Ok. I’ll chime in here as a Bruel & Kjaer Technical specialist. Ask away. We do make many great reference microphones and sound level meters that are even more “flat” as we use DSP FIR EQ to optimize response. For instance our 4966 1/2 inch free field mic 0° axis is really flat out to 12kHz and take a little .7dB bump out to 19kHz.
When used on our $2500 type 2245 SLM we get rid of the bump - though the body of the SLM gives us a very slight 0.25 dB ripple.
Ask question about the world’s reference microphones. Or maybe I’ll start a new topic.

No questions. The mic is just happily doing it's job without fuss or complaint.