Measurement Microphones - what is the consensus?

[stemfencer]

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, besides the advice of get a calibration specific microphone, or just buying a UMIK, is there much benefit going up the chain? Or are the $40 Behringer/Superlux all anyone needs? Obviously we are omitting people aspiring for laboratory grade measurements from this discussion.

Searching around I came across this Jochen Schulz blog post which best addresses the topic. The headline takeaway was anything below 4k Hz the perennial $30 Behringer EMC8000 is more than good enough for the home enthusiast, especially as set-up problems predominately lay in bass region. Has anyone done similar comparisons or experiences with multiple mics concur?

 

[DVDdoug]

I don't think it's too critical as long as it's "individually calibrated" and if you trust the company to calibrate it accurately. I wouldn't trust an unknown brand off of eBay or AliExpress.

A USB measurement mic has an advantage over an analog mic in-that the digital dB level is calibrated to the SPL level. An analog measurement mic has calibrated (measured & published) frequency response but the digital level depends on the gain of the preamp/interface, so that has to be calibrated separately (by you) if that's important.


... A little different situation but I have one of those old Radio Shack SPL meters. It's rumored that electret condenser mics lose their sensitivity over the years, so I was wondering if it was still accurate. So I bought a calibrator for about the same price as a cheap SPL meter. Amazingly, the cheap & old SPL meter was "perfect" (as accurately as I could read the analog meter.)

The headline takeaway was anything below 4k Hz the

That's pretty much true. Most "big" acoustic/room problems are in the lower frequencies. And at higher frequencies (shorter wavelengths) things get "complicated" and if you move the mic a little, or if you are moving around in the room, the readings can change by a few dB or more.

 

[HarmonicTHD]

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, besides the advice of get a calibration specific microphone, or just buying a UMIK, is there much benefit going up the chain? Or are the $40 Behringer/Superlux all anyone needs? Obviously we are omitting people aspiring for laboratory grade measurements from this discussion.

Searching around I came across this Jochen Schulz blog post which best addresses the topic. The headline takeaway was anything below 4k Hz the perennial $30 Behringer EMC8000 is more than good enough for the home enthusiast, especially as set-up problems predominately lay in bass region. Has anyone done similar comparisons or experiences with multiple mics concur?

Well. Most here are measuring equipment worth thousands, so why worry saving 60 bucks on a mic, which might lead to dodgy results when you get a calibrated UMIK for 100 bucks and plenty of support here on how to set it up here.

 

[stemfencer]

Well. Most here are measuring equipment worth thousands, so why worry saving 60 bucks on a mic, which might lead to dodgy results when you get a calibrated UMIK for 100 bucks and plenty of support here on how to set it up here.

Yeah I'm leaning towards this. I already have audio interface and cables, so though XLR mic would be more bang for buck as I'm not concerned about SPL monitoring, however the UMIK-1 is recommended and used everywhere it seems.

 

[HarmonicTHD]

Yeah I'm leaning towards this. I already have audio interface and cables, so though XLR mic would be more bang for buck as I'm not concerned about SPL monitoring, however the UMIK-1 is recommended and used everywhere it seems.

I hear you. I also have an audio interface with XLR/48V. I haven’t found a XLR mic solution yet, with a calibration file, which then also considers the gain in the audio interface and gives quick and halfway reliable absolute SPL values. I therefore went for the UMIK as the whole setup is also more mobile (just Laptop and UMIK).

 

[sarumbear]

Has anyone considered or used the AudioTools software suit?

Due to the vast scale manufacturing of iPhone part tolerances are very small. This results in a microphone with very tight tolerances which can be pre-calibrated with good results. I own a MLSSA and CLIO test system with a calibrated B&K microphone. I tested AudioTools against them and the deviation was within +1/-0.5dB.

I find that using an iPhone/iPad is miles easier than using an external microphone and a laptop.

 

[Postlan]

Does anyone offer calibrating my cheap mic at a reasonable cost in US?

 

[Jukka]

Has anyone considered or used the AudioTools software suit?

Due to the vast scale manufacturing of iPhone part tolerances are very small. This results in a microphone with very tight tolerances which can be pre-calibrated with good results. I own a MLSSA and CLIO test system with a calibrated B&K microphone. I tested AudioTools against them and the deviation was within +1/-0.5dB.

I find that using an iPhone/iPad is miles easier than using an external microphone and a laptop.

I would not trust a mobile device mic for room acoustic measurement. The mics in these devices are not purposed for full range measurement, so you might not have reliable down to 20 Hz. Also for room acoustics you need omni-pattern mic, what is the pattern for a phone?

 

[Snarfie]

I have a Superlux measuring mic for just 38,-. Made same measurment used for Lingdorf a UMIK an some others with mic's that where way more expensive results were basicly the same by sight an hearing/comparison result.

 

[Curvature]

The headline takeaway was anything below 4k Hz ... is more than good enough

That's poorly worded and misrepresents the article.

The right way to put it is that any mic you buy must come with a calibration file. That acts as proof of performance and makes price less important.

Certain companies will cerify their mics within a tolerance (IEC 61672).

The actual performance without calibration can vary a great deal. Look at this collection for the miniDSP UMIK-1:



And the Behringer ECM8000:



Proof is what's important, not "good enough" logic.

 

[FeddyLost]

is there much benefit going up the chain?

IMO if you are using this mic for commercial purposes (making/tuning speakers for sale, calibrating some other's HT/studio, making your own studio) the calibration file is a must.
If you are trying to treat your own HT, everything is up to you.
Personally I use ECM8000 without proper cal file and just don't try to make a flat FR at all costs.
Maybe one day I'll buy calibrated mic, but subjective result is already OK now.

 

[No. 5]

For the average home enthusiast looking to optimise their set-up, besides the advice of get a calibration specific microphone, or just buying a UMIK, is there much benefit going up the chain? Or are the $40 Behringer/Superlux all anyone needs? Obviously we are omitting people aspiring for laboratory grade measurements from this discussion.

Searching around I came across this Jochen Schulz blog post which best addresses the topic. The headline takeaway was anything below 4k Hz the perennial $30 Behringer EMC8000 is more than good enough for the home enthusiast, especially as set-up problems predominately lay in bass region. Has anyone done similar comparisons or experiences with multiple mics concur?

I've compared a calibrated ECM8000 to an AVR's setup mic, and a $2 lavalier off eBay, I'd happily use any one of them for doing low frequency setup.

On the other hand, if I was doing anything full-range and want precision, I'd use the ECM. I often use the setup mic when I don't want to drag out my good test equipment. So I guess it depends on what you're looking to do. If you want to do something simple at low frequency, like EQ some peaks, blend a couple subwoofers, or get your crossover to them straightened out, even your phone will work for that. So will the setup mic that came with your AVR. Or an ECM8000. Up to the enthusiast and how much they want to spend.

I would not trust a mobile device mic for room acoustic measurement. The mics in these devices are not purposed for full range measurement, so you might not have reliable down to 20 Hz. Also for room acoustics you need omni-pattern mic, what is the pattern for a phone?

I've found smartphone's to be a useful tool for room acoustics. I'm not looking for precision with one, because I know they don't have it, but it's a quick and handy way to pick out a resonance or identify a corner frequency. Sure it's solidly a Type 3 microphone, but below a few hundred hertz, I'd be surprised if it wasn't omni.

 

[Curvature]

I've compared a calibrated ECM8000 to an AVR's setup mic, and a $2 lavalier off eBay, I'd happily use any one of them for doing low frequency setup.

On the other hand, if I was doing anything full-range and want precision, I'd use the ECM. I often use the setup mic when I don't want to drag out my good test equipment. So I guess it depends on what you're looking to do. If you want to do something simple at low frequency, like EQ some peaks, blend a couple subwoofers, or get your crossover to them straightened out, even your phone will work for that. So will the setup mic that came with your AVR. Or an ECM8000. Up to the enthusiast and how much they want to spend.


I've found smartphone's to be a useful tool for room acoustics. I'm not looking for precision with one, because I know they don't have it, but it's a quick and handy way to pick out a resonance or identify a corner frequency. Sure it's solidly a Type 3 microphone, but below a few hundred hertz, I'd be surprised if it wasn't omni.

Lavalier mics boost high frequencies and have pronounced low frequency roll off, along with variable polar patterns.

Whatever comparison you made wasn't sufficient to bring out differences. Don't give random advice like that.

The fact that the room dominates at low frequencies is no reason to use wrong or inaccurate tools.

 

[No. 5]

Lavalier mics boost high frequencies and have pronounced low frequency roll off, along with variable polar patterns.

Whatever comparison you made wasn't sufficient to bring out differences. Don't give random advice like that.

The fact that the room dominates at low frequencies is no reason to use wrong or inaccurate tools.

Sigh... at least my mom thinks I'm cool.

My comparison brought out those differences just fine, but notice a key part in my previous post:

If you want to do something simple at low frequency

The lavalier I tested was less than 10dB down by 20Hz, but if all you are using it for is identifying the center frequencies and approximate Q of resonances that need to be cut down, how does that matter? It matters if you're doing a house curve, it matters if you want to know what your actual response is, but for the things that I said I'd use it for... not so much.

True, lavaliers often have a high frequency boost, but I didn't suggest using it at high frequency, and it's true that other examples will have steeper roll off, but the one I tested did not so I felt it reasonable to say that I would use one.

 

[Curvature]

Sigh... at least my mom thinks I'm cool.

My comparison brought out those differences just fine, but notice a key part in my previous post:

The lavalier I tested was less than 10dB down by 20Hz, but if all you are using it for is identifying the center frequencies and approximate Q of resonances that need to be cut down, how does that matter? It matters if you're doing a house curve, it matters if you want to know what your actual response is, but for the things that I said I'd use it for... not so much.

True, lavaliers often have a high frequency boost, but I didn't suggest using it at high frequency, and it's true that other examples will have steeper roll off, but the one I tested did not so I felt it reasonable to say that I would use one.

You are assuming the degree of error is low enough not to matter. I can't accept that. Too many unknowns are compounded: microphone response, speaker radiation (especially for the many models out there that have no comprehensive measurements), and room effects. Some certainty has to be introduced to make corrective action matter. Otherwise it's all blind work and tweaking.

Think about it: you are asking people to tweak with powerful tools like EQ, instead of weak ones like cable lifters (or whatever). You may think the comparison is off, but I don't. I see your advice feeding the overwhelming obsessive compulsive urge in audio to try stuff randomly without understanding what's at play.

 

[morpheusX]

I have an UMIK-1 calibrated by CSL, and recently compared it to a regular ECM8000.
Excluding potential diferences with positioning, i was impressed on how accurate the ECM8000 was:

 

[No. 5]

You are assuming the degree of error is low enough not to matter.

No, you are assuming that the error in question will affect my explicitly stated use case.

Too many unknowns are compounded: microphone response, speaker radiation (especially for the many models out there that have no comprehensive measurements), and room effects. Some certainty has to be introduced to make corrective action matter. Otherwise it's all blind work and tweaking.

Exactly, blind work and tweaking will result in very undesirable results which is why a microphone is vital. Improving low frequency performance of a system can be done by reducing low frequency peaks if the center frequency and Q is known, and any microphone will reveal that information. Calibrated or not. Same goes for setting a subwoofer's crossover frequency, you need to know the corner frequency of the filter or the acoustic roll-off, but a microphone doesn't need to be calibrated to show that. And for adding multiple subwoofers too, you can see how they sum together without a calibrated microphone.

I'm talking about looking at a specific attitude that speaker radiation and microphone roll-off have little bearing on. I'm concentrating on the peaks and dips.

Think about it: you are asking people to tweak with powerful tools like EQ, instead of weak ones like cable lifters (or whatever). You may think the comparison is off, but I don't. I see your advice feeding the overwhelming obsessive compulsive urge in audio to try stuff randomly without understanding what's at play.

I'm pointing out that there's inexpensive measurement tools available. That is all. You are right that person must come to understand what a measurement is telling them for it to be of any use, but you must also know that quality and cost of the microphone has no effect on that understanding. Hands-on experience can, and some might be motivated to get that experience if they know they can use something very affordable or that they already have on hand.

 

[jhaider]

I think don’t let the tool get in the way of the work. I have a few different ones CSL calibrated Dayton EMM-6 and UMIK-1, iSEMcon EMX, a matched pair of Earthworks M30. In practice I think all of the above give me useful data.

I’m a little afraid to use the “best” ones, the M30s. I should really take the hit and sell them. I’ve never taken them outside. I don’t think they’re fragile, but I don’t want to scratch the nice wooden case either! EW also does not offer individualized grazing incidence (DF) calibration curves. On axis only, and a generic DF curve.

 

[Blumlein 88]

No, you are assuming that the error in question will affect my explicitly stated use case.

Exactly, blind work and tweaking will result in very undesirable results which is why a microphone is vital. Improving low frequency performance of a system can be done by reducing low frequency peaks if the center frequency and Q is known, and any microphone will reveal that information. Calibrated or not. Same goes for setting a subwoofer's crossover frequency, you need to know the corner frequency of the filter or the acoustic roll-off, but a microphone doesn't need to be calibrated to show that. And for adding multiple subwoofers too, you can see how they sum together without a calibrated microphone.

I'm talking about looking at a specific attitude that speaker radiation and microphone roll-off have little bearing on. I'm concentrating on the peaks and dips.

I'm pointing out that there's inexpensive measurement tools available. That is all. You are right that person must come to understand what a measurement is telling them for it to be of any use, but you must also know that quality and cost of the microphone has no effect on that understanding. Hands-on experience can, and some might be motivated to get that experience if they know they can use something very affordable or that they already have on hand.

Yes, if you know the limitations of your tools you can do work with them when others might scoff at the idea. Almost any condenser or electret omni is good to about 2 khz. Certainly for the lower 500 hz which is where room effects are predominate they are fine. By good I mean they will be very, very flat in response. We'd all love to have lab grade microphones, but you can do lots with less. I'd love to have @jhaider 's M30's maybe if he decides to sell them I'd be a possible customer. As it is I use a Umik-1 and even a calibrated Dayton Audio iMM-6 with a phone or laptop. I think I paid $24 for it though they have gone up since then.

 

[Ron Texas]

How good do they have to be?