The humble SM58 as a test microphone.

[5ynth3t1k]

I know the mic is not the mic of choice BUT it is a mic. They do work. and sometimes any measurement is better that none, at the very least you can measure two things with the same mic and compare the results. ( Science ! )

So... if I was to say want to measure the spectrum of noise coming out of something and I had this mic, a preamp and a PC ....

Where would I start ? (I am not going to buy a dedicated measurement mic. Well, not yet )

As the SM58 is a celebrated Mic and I have one, I would like to use it.

What software should I use ?, is there some basic software that is not going to require the loss of a kidney ? and it works on all versions of windows ? ( I am a Luddite and still use win7 ...)

Thanks !

 

[MAB]

Any decent mic interface or soundcard will suffice.

REW is a good tool to capture and analyze. There are some helpful threads, perhaps this one to get started and explore.

If the SM58's Frequency Response were reliable, it would be more useful. Cardioid pattern will change the bass EQ with close proximity. The directionality will mess with you as well. But it is a start, and you likely want to spend a small amount on a proper measurement mic after getting going.

Measurement mics aren't too expensive. UMIK-1 is a good USB mic that doesn't even need an interface, is under $150. There are even cheaper models. I use an old Nakamichi mic with a small omni capsule, a UMIK, and an Earthworks, they all work really well. The Earthworks is the best in some cases, but for most work even the old Nakamichi works great. The UMIK-1 is so easy due to being USB. Not sure what else is available in your region.

 

[Everett T]

I know the mic is not the mic of choice BUT it is a mic. They do work. and sometimes any measurement is better that none, at the very least you can measure two things with the same mic and compare the results. ( Science ! )

So... if I was to say want to measure the spectrum of noise coming out of something and I had this mic, a preamp and a PC ....

Where would I start ? (I am not going to buy a dedicated measurement mic. Well, not yet )

As the SM58 is a celebrated Mic and I have one, I would like to use it.

What software should I use ?, is there some basic software that is not going to require the loss of a kidney ? and it works on all versions of windows ? ( I am a Luddite and still use win7 ...)

Thanks !

I use this mic regularly at out church, never have had any issues for the content we need it for. I have a couple of the Behringer clones but they're hit or miss.

 

[5ynth3t1k]

Any decent mic interface or soundcard will suffice.

REW is a good tool to capture and analyze. There are some helpful threads, perhaps this one to get started and explore.

If the SM58's Frequency Response were reliable, it would be more useful. Cardioid pattern will change the bass EQ with close proximity. The directionality will mess with you as well. But it is a start, and you likely want to spend a small amount on a proper measurement mic after getting going.

Measurement mics aren't too expensive. UMIK-1 is a good USB mic that doesn't even need an interface, is under $150. There are even cheaper models. I use an old Nakamichi mic with a small omni capsule, a UMIK, and an Earthworks, they all work really well. The Earthworks is the best in some cases, but for most work even the old Nakamichi works great. The UMIK-1 is so easy due to being USB. Not sure what else is available in your region.

What does this mean : " If the SM58's Frequency Response were reliable ..."

Is there some kind of manufacturing variation in the mics ? Old versus new ? I cannot imagine over the many decades of production that they all sound the same...

One day I will get a Umik but not right now. and i would have to import it, which means hassle.... etc

Maybe I just ditch the SM58 idea. Hmm....

 

[DVDdoug]

at the very least you can measure two things with the same mic and compare the results. ( Science ! )

Sure! A 3dB difference is a 3dB difference. Microphones are linear and the difference or change will be correct as long as you're not down in the noise. And the SM58 is almost impossible to overload so there are no limits on the loud side.

The Shure Website has a frequency response curve for the SM58 frequency response curve and the REW website has an example of what a calibration file so you should be able to make a rough calibration file.

What does this mean : " If the SM58's Frequency Response were reliable ..."

It's "typical" and yes, there are tolerances/variations. Measurement mics are individually measured and the calibration file is associated with a particular serial number.

And, the graph doesn't show a lot of precision and it doesn't show the "full' 20-20kHz range.

Note that with an analog mic the SPL isn't calibrated to the digital level... The digital level depends on the analog gain and ADC calibration. If you have an SPL meter you can make a calibration, but it only stays calibrated until you touch the gain knob on your audio interface.

 

[scrubb]

The Shure Website has a frequency response curve for the SM58 frequency response curve and the REW website has an example of what a calibration file so you should be able to make a rough calibration file.

Yes, and the curve shows that response drops off quickly and severely below 100Hz. The curve doesn't even go below 50Hz and I suspect it picks up very little if anything below 50. In my live sound mixing past I once had no option but to use an SM58 to mic a kick drum. The results were less than sufficient. I don't think an SM58 would work very well at all as a test microphone, which needs to pick up 20-20k Hz.

 

[MAB]

What does this mean : " If the SM58's Frequency Response were reliable ..."

Is there some kind of manufacturing variation in the mics ? Old versus new ? I cannot imagine over the many decades of production that they all sound the same...

One day I will get a Umik but not right now. and i would have to import it, which means hassle.... etc

Maybe I just ditch the SM58 idea. Hmm....

Sorry, not a good word-choice on my part.

The problem is the cardioid characteristic. If you change the distance to the sound source, the bass EQ changes. If you rotate the mic relative to the sound source, the midrange and treble changes. It will have strongly position-dependent EQ compared to even the cheapest measurement mics.

The mic itself is reliable. If you already have a mic interface, it will get you started, although I would plan on moving to a proper measurement mic. If you don't have an interface, perhaps a USB mic is the way to go.

 

[LTig]

Yes, and the curve shows that response drops off quickly and severely below 100Hz. The curve doesn't even go below 50Hz and I suspect it picks up very little if anything below 50. In my live sound mixing past I once had no option but to use an SM58 to mic a kick drum. The results were less than sufficient. I don't think an SM58 would work very well at all as a test microphone, which needs to pick up 20-20k Hz.

Yep. A dirt cheap Behringer ECM 8000 is much better, even non calibrated.

 

[Weeb Labs]

Another excellent option is the Dayton iMM-6C. It is within 1dB of the UMIK-1, retails for €45 and doesn't require an audio interface.

 

[Barrelhouse Solly]

The SM-58 is a vocal mic. It's a small club workhorse. If you hear bands in small clubs there's a good chance that's what the vocalist(s) use. The SM-57 is its instrument mic counterpart. Neither is good as a calibration mic. They're not really designed for it. As others have suggested, the Dayton and Behringer are good inexpensive choices. They're under $100 and are close to flat over the range you're looking for for calibration. The Dayton has a calibration file for each mic that you can download. The Behringer doesn't.

 

[Waxx]

studio and live microphones (the SM58 fits both roles) are not neutral in many cases, and that is intended. They are build to fit a certain sound that the recording engineer uses to make the total sound of the production. Neutral mics like measurement microphones are uselesss here. Even for classical music a directivity and colouration is often wanted.

For measurements that tonal signature will disort the measurements, except when you have a calibration file that conquer that, and when the microphone is omnidirectional (the SM58 is cardioid, so not usefull).

 

[SSS]

The SM58 is in no mean a measurement microphone. It is just made vor vocal. Even the shure data say vocal application. One would need to take a calibration curve of the individual SM58. But with lack of the very lows and upper highs calibration may not be really sufficient. What is not there it can not be created. But anyway the SM58 is for vocal a good mic.

 

[5ynth3t1k]

Sure but it's what I have right now. and it does hear things.

the ECM8000 is out of stock at my local stores. Drat.

Cheers for the input. :- )

 

[DonH56]

This is the SM58's frequency response from Shure:

It rolls off below 100 Hz and has the (in)famous "presence boost" starting above 2 kHz and peaking around 5 kHz, with some perturbations in response up to 9 kHz before falling off, about -5 dB around 12 kHz. A measurement system without mic compensation will thus determine bass below 100 Hz is too low, upper midrange and treble up to 10 kHz or so too high, and response too low beyond maybe 12 kHz. Correcting the measured response without considering the microphone's response would lead to excessive bass (since it measured low) and suppressed upper midrange/lower treble (since it measured high), likely causing boomy bass and "dead" sound without high-end "clarity" or "life". If you use it for measurements, you must keep the mic's response in mind, and apply (actually or mentally) a compensation curve to obtain flat response by correcting for the microphone's response. Even then, the large amount of correction required for low bass makes its use (in my mind anyway) impractical for deep bass and subwoofer measurements; ditto for high-frequency response from ~12 kHz to 20 kHz.

FWIWFM - Don

 

[Palmer]

The Behringer ECM8000 was 20.- bucks at Amazon a couple of months ago, which I posted on the corresponding thread. Did not get much of a response to that, but despite having one - I bought 3 more. It pays to keep an eye on the ASR - even if the topic of a thread is not quite what one is interested in. My 2 cents...

 

[DonH56]

The UMIK-1 is another low-cost (~$100) measurement mic option. Mine's frequency response with its calibration file essentially matches my Earthworks M30, a much more expensive measurement mic. It won't match the dynamic range, uncalibrated flatness, and low noise of the M30, but for most audio measurements the Umik-1 (and ECM8000) provide great performance. The Dayton is an even cheaper alternative with more than adequate performance for typical sound measurements (higher noise floor IIRC but I have not looked at it in a while so may be wrong on that).

If the Umik-1 and REW software were available decades ago I would have saved a lot of money (and shelf space) on sound measuring equipment.

 

[Flaesh]

to measure the spectrum of noise coming out of something

For such purposes it may (or may not) be sufficient, depending on the requirements for the measurements....