Dayton iMM-6 vs miniDSP UMIK-1

[csepulv]

I had been using a Dayton Audio iMM-6 calibrated microphone for REW measurements. It is fairly cheap ($20). But I just bought a miniDSP DDRC-24 kit, which came with the UMIK-1. So I used REW to take some measurements, to see how the UMIK-1 compared to the iMM-6.

I expected differences, but they seem much larger than I expected.

Red=iMM-6, Blue=UMIK-1: pure mode (on AVR), no EQ.

As started to google and read about the iMM6, it seems others have noted it doesn't record bass. But there is also the odd peak around 16k. I've done numerous measurements. I even tried some older speakers I had and they show the same 15-16k peaks.

Could I be doing something wrong in REW? (I did't change any settings other than selecting a different input.)

Or is this just the limitations of $20 iMM-6 vs $80 UMIK-1?

 

[Jdunk54nl]

Did you insert the calibration file into REW for each microphone?

 

[abdo123]

iMM6 seems to be using a capsule that is meant for recording vocals.

 

[Tangband]

I had been using a Dayton Audio iMM-6 calibrated microphone for REW measurements. It is fairly cheap ($20). But I just bought a miniDSP DDRC-24 kit, which came with the UMIK-1. So I used REW to take some measurements, to see how the UMIK-1 compared to the iMM-6.

I expected differences, but they seem much larger than I expected.


View attachment 162321
Red=iMM-6, Blue=UMIK-1: pure mode (on AVR), no EQ.

As started to google and read about the iMM6, it seems others have noted it doesn't record bass. But there is also the odd peak around 16k. I've done numerous measurements. I even tried some older speakers I had and they show the same 15-16k peaks.

Could I be doing something wrong in REW? (I did't change any settings other than selecting a different input.)

Or is this just the limitations of $20 iMM-6 vs $80 UMIK-1?

thats the difference one can expect with cheaper capsules, the variation can be +-10 dB between different units of the same mic. You cannot be shure either that your UMIK is perfectly flat. You also need to use audiotools in your iphone for imm6 - from iOS 6 and above the high pass filtering is disconnected and the mics measures much better.

I have two Line audio OM1 and one of them I had to replace after I had them examined. It differed slightly more than the spec at +-1 dB 20-20000 Hz. The imm6 I had some years ago was within +-3 dB 100-20000 Hz.

csepulv : The standard for proffesional measurements is a measurement-window of 50 dB . Now you have it on 130 dB, making everything look flat. You can change the REW program to 50 dB window.

 

[csepulv]

Did you insert the calibration file into REW for each microphone?

Yes.

thats the difference one can expect with cheaper capsules, the variation can be +-10 dB between different units of the same mic. You cannot be shure either that your UMIK is perfectly flat. You also need to use audiotools in your iphone for imm6 - from iOS 6 and above the high pass filtering is disconnected and the mics measures much better.

I have two Line audio OM1 and one of them I had to replace after I had them examined. It differed slightly more than the spec at +-1 dB 20-20000 Hz. The imm6 I had some years ago was within +-3 dB 100-20000 Hz.

Good to know. While I can't be certain about the umik-1, it is probably the better mic to use. I'll see how it does as I start to run Dirac Live on the miniDSP

 

[Tangband]

Yes.


Good to know. While I can't be certain about the umik-1, it is probably the better mic to use. I'll see how it does as I start to run Dirac Live on the miniDSP

Good luck !
..( just change the measurement window to 50 dB )

One more thing : If you have had your mics 20 cm different when measuring, then its almost enough to make the differences you have discovered , even if the mics would be identical they would then measure very differently.

The mics should be at +-0,5 cm at the same distance and hight when doing comparisons.

 

[Blumlein 88]

I wondered about the positioning. You do have to get it very close to the same position for comparing like this. I've both microphones and have gotten much closer agreement between them. Maybe I got lucky or maybe you got unlucky.

One thing making me suspicious of the positioning is when I've done this with the Umik, the Dayton and a few omni recording microphones, the curves from about 1 khz and lower just almost lay on top of each other. And above 1 khz I generally have less difference than you do in your graphs.

Here is an overlay of a Umik 1(red), Avantone CK-1 omni SDC (green), and CAD M179 omni LDC(blue).

 

[thewas]

I am quite sure that the shown irregular differences between both are the result of not exact same placement, except in the bass region where the large deviation seems to be resulting of a high pass filter.

Even cheap mics usually mainly deviate on the two extremes of the audio band and don't have irregular bumps and dips, see

Hifi-Selbstbau - 1000 Mikrofonkalibrierungen - eine Übersicht

HiFi-Selbstbau - Das Online-Magazin

www.hifi-selbstbau.de

 

[Jdunk54nl]

Try pink periodic noise generated by REW and moving the microphone around to get an average via the RTA screen. About 100 averages should be good.

I’d bet that gets a lot closer results. Erin (Erin’s audio corner) has a YouTube video explaining how to do moving mic if you are unsure.

 

[Blumlein 88]

Try pink periodic noise generated by REW and moving the microphone around to get an average via the RTA screen. About 100 averages should be good.

I’d bet that gets a lot closer results. Erin (Erin’s audio corner) has a YouTube video explaining how to do moving mic if you are unsure.

I started to suggest this and it is a good idea.

 

[MaxRockbin]

I don't have any personal experience with this, but just to complicate things and add an alternative--another low cost measurement mic recommended by a guy with a youtube channel who does studio treatment: Behringer ECM8000
As of right now, $29 on sweetwater, $32 on Thomann.

 

[csepulv]

A few people have noted listening position as a possible issue. Here is a plot I did a few weeks ago from a several different listening positions. This is with the DT iMM-6. They all show the spike at 16k.

At the time, I assumed the 16k spike was the brightness I've read (here) is typical of Paradigm speakers. I had an older set of Paradigms, saw a similar spike and attributed to the brand. ‍

With umik-1, I suspect the imm-6 is a problem. As @Tangband noted, it could just be dumb luck with a bad imm-6.

Not that the umik-1 is perfect, but worth experimenting. I will try the suggestion of pink noise and the moving mic method.

 

[csepulv]

I tried the moving mic captures, with RTA and full range pink noise (100+ averages). The imm-6 shows a larger ~16k peak, but it is there with the umik-1 as well. I suppose that is part of the Paradigm "sound".

RTA settings, fwiw

For these captures, the only thing I changed was the input device in REW.

 

[Jdunk54nl]

Ideally with periodic pink noise you would have your window set to rectangular instead of Hann. Not a huge issue and not going to drastically change anything. Just for future info. My friend explained this reasoning to me a long time ago and I have since forgot it. It isn't just a "friend" either. Their job is dsp stuff and they know all of the equations and things behind the scenes and why. They will soon have their masters degree in this stuff. So I trust their reasoning, and it seemed logical at the time.

 

[Jdunk54nl]

I don't have any personal experience with this, but just to complicate things and add an alternative--another low cost measurement mic recommended by a guy with a youtube channel who does studio treatment: Behringer ECM8000
As of right now, $29 on sweetwater, $32 on Thomann.

That would require some type of XLR computer interface. SO well it is $29, you also have to spend money on a focusrite 2i2 or motu m2 at minimum to get it to work with REW. I would strongly suggest it though, you can get A LOT more information in real time using something like that over a USB microphone.
I have a couple of usb microphones and a couple XLR microphones with a motu m4. For quick frequency checks I pull out the usb, but 99% of the time I just get the xlr and motu out and use SMAART (or there is free software Open Sound Meter if you don't own SMAART)

 

[csepulv]

Ideally with periodic pink noise you would have your window set to rectangular instead of Hann. Not a huge issue and not going to drastically change anything. Just for future info. My friend explained this reasoning to me a long time ago and I have since forgot it. It isn't just a "friend" either. Their job is dsp stuff and they know all of the equations and things behind the scenes and why. They will soon have their masters degree in this stuff. So I trust their reasoning, and it seemed logical at the time.

Thanks for the tip. I will try using rectangular.

 

[kyle_neuron]

I don't have any personal experience with this, but just to complicate things and add an alternative--another low cost measurement mic recommended by a guy with a youtube channel who does studio treatment: Behringer ECM8000
As of right now, $29 on sweetwater, $32 on Thomann.

These used to be pretty good, but the later models appear to have cheaper electronics and strange specs.

For cheap mics, I recommend the Sonarworks XREF20. You need to find a supplier who will sell them, since they’re meant to only be replacements for the bundled one with the software.

It’s the same ODM as the Behringer, but the build quality is better, and they are more stable in a wider range of temperatures and humidities. You also get a calibration file for each individual mic. I’ve measured up to 125 dB linear without the mic capsule distorting too, which beats the Behringer ECM8000 I’ve tested.

I own some Earthworks M23, M30 and isemCON EMX-7150 as well as the dbx RTA mic, and the aforementioned Behringer. I also regularly use very expensive B&K mics and preamps. For most field work, I use the three Sonarworks mics I own, because they’re good enough for 90% of the audible range and multi-mic measurements are the way forward.

If it came to starting over, I’d prefer to spend $300 on three of those than one Earthworks

Software-wise, REW now supports multiple mics for $100. I don’t think real-time mode is necessary in many applications outside of gigs and you get a lot in REW. I use SysTune, Smaart, RoomCapture, EASERA, CLIO and CrossLite+ in the day job, but REW is up there. My next choice these days is CrossLite, easily.

 

[Emane]

For most field work, I use the three Sonarworks mics I own, because they’re good enough for 90% of the audible range and multi-mic measurements are the way forward.

Which 10% of the audible range is it not good enough for?
Would you recommend the Sonarworks XREF20 for spin-o-rama type speaker measurements?

 

[MauriceG]

I had been using a Dayton Audio iMM-6 calibrated microphone for REW measurements. It is fairly cheap ($20). But I just bought a miniDSP DDRC-24 kit, which came with the UMIK-1. So I used REW to take some measurements, to see how the UMIK-1 compared to the iMM-6.

I expected differences, but they seem much larger than I expected.


View attachment 162321
Red=iMM-6, Blue=UMIK-1: pure mode (on AVR), no EQ.

As started to google and read about the iMM6, it seems others have noted it doesn't record bass. But there is also the odd peak around 16k. I've done numerous measurements. I even tried some older speakers I had and they show the same 15-16k peaks.

Could I be doing something wrong in REW? (I did't change any settings other than selecting a different input.)

Or is this just the limitations of $20 iMM-6 vs $80 UMIK-1?

This might be a really dumb suggestion, if so, sorry. I installed REW on a Macbook. To start with: you must connect headphones to the eMM-6 when you insert it in the headphone connector of the Macbook. Otherwise you can not select the eMM-6 external microphone (i.e. You can only select the internal microphone). Next, please make sure that, in settings, the background noise filter is turned off (by default it is turned on by MacOS)

 

[thecity2]

How does the Dayton UMM6 compare to these other mics?