Using Microphone as SPL Meter

[BoredErica]

I have Earthworks M23. I'd like to convey how loud my music is when I listen to music on average but am unsure what the best way to do that is. First the weighting: I'm assuming C or Z weighted is best? Since these weightings do not roll off at bass like A weighting, I assume the average levels will vary based on how bass heavy a track is?

Then there's the measurement part. In REW I'm supposed to calibrate the mic before I use SPL meter feature but to do so I need a mic. Ok, if I could get reliable measurements of volume with a SPL meter to calibrate my mic, why wouldn't I just use the SPL meter instead? I just have a $35 Amazon SPL meter and it's A-weighted. Do I have to buy a C weighted SPL meter and if so which one? This page from REW seems to talk about process of mic calibration w/ SPL meter, but it's unclear to me what weighting the SPL meter is supposed to be. Maybe I'm just too tired or lack reading comprehension.

In this post solderdude seems to say cheap SPL meters are bad for measuring music and only ok for measuring noise levels, but it's unclear to me if they meant the A weighting or the meters just being poorly made.

Listening to music as loud as I want it, $35 A weighted meter measures 66dba and REW w/ M23 calibrated w/ A weighted meter measures 73dbz. Is it fair for me to say I listen to music approx 73dbz or are my estimates so far off as to be meaningless?

I measured pink noise w/ an app on my phone and my cheap SPL meter, both A weighted, and they clearly get significantly different readings...

I did an estimation of power requirements: At 1.92M from speakers (farthest I'd ever wanna be), with volume of 74+15db SPL (+15db for peaks), sensitivity of 83db, 7db headroom (10db for EQ, 3db extra on top, -3 for 2 speakers, -3 for room gain), power required is 74w.

 

[Sokel]

You can calibrate it after choosing the weighting in the middle,it then appears at the top next to the value:

Better calibrate it with speaker signal,subwoofer signal won't appear right in A weighting.

 

[Sokel]

After the calibration you can use the Logger to see the various values (average,max,peak,etc) while listening to your music:

 

[BoredErica]

You can calibrate it after choosing the weighting in the middle,it then appears at the top next to the value:

View attachment 291463

Better calibrate it with speaker signal,subwoofer signal won't appear right in A weighting.

I'm sorry, I'm still confused. I understand that calibrating w/ speaker signal makes more sense than subwoofer signal and that's what I use. But no matter what weighting I click, as soon as I hit Calibrate, it goes to C and doesn't let me change it during calibration. It seems to always calibrate at C weighting. I can change it from C weighting post-calibration but this gives me the impression that my SPL meter is supposed to be C weighted.

 

[Sokel]

Oh,so that what you mean,yes it better be C weighted.
But you can always check after the calibration against your meter and your phone for example,some apps let you choose weighting just to see if you're close.
You won't land far,don't worry.

 

[dualazmak]

Just for your possible interest and reference, I DIY-ed IEC60268-17 compatible 12-VU-Meter Array monitoring SP high-level output signals from my multiple amplifiers using reliable High-to-Low (into line level) converters; the VU-Meters' swing ranges/responses were correlated/adjusted to actual air SPL at my listening position measured by a measurement microphone BEHRINGER ECM8000 (please refer here).

You can find my latest system setup including the IEC60268-17 compatible 12-VU-Meter Array here and here.

If you would be interested, please refer to my posts on my project thread;

- My nostalgia and preference for large glass-face VU meters: DIY of 12-VU-Meter Array in multichannel multi-driver multi-way multi-amplifier stereo audio system: #535
- NISHIZAWA R-65 VU meter plus ATV205EXT VU amp board is compatible with IEC 60268-17 VU meter specification/standard: #545
- Dancing video of my IEC 60268-17 compatible large glass-face DIY 12-VU-Meter Array
_____Part-1: with "High Frequency Linearity Check Track" of Sony Super Audio Check CD: #750
_____Part-2: with typical "Full Orchestra Music"-1: #751
_____Part-3: with typical "Full Orchestra Music"-2: #752
_____Part-4: with typical "Jazz Piano Trio Music": #753

 

[HarmonicTHD]

I have Earthworks M23. I'd like to convey how loud my music is when I listen to music on average but am unsure what the best way to do that is. First the weighting: I'm assuming C or Z weighted is best? Since these weightings do not roll off at bass like A weighting, I assume the average levels will vary based on how bass heavy a track is?

Then there's the measurement part. In REW I'm supposed to calibrate the mic before I use SPL meter feature but to do so I need a mic. Ok, if I could get reliable measurements of volume with a SPL meter to calibrate my mic, why wouldn't I just use the SPL meter instead? I just have a $35 Amazon SPL meter and it's A-weighted. Do I have to buy a C weighted SPL meter and if so which one? This page from REW seems to talk about process of mic calibration w/ SPL meter, but it's unclear to me what weighting the SPL meter is supposed to be. Maybe I'm just too tired or lack reading comprehension.

In this post solderdude seems to say cheap SPL meters are bad for measuring music and only ok for measuring noise levels, but it's unclear to me if they meant the A weighting or the meters just being poorly made.

Listening to music as loud as I want it, $35 A weighted meter measures 66dba and REW w/ M23 calibrated w/ A weighted meter measures 73dbz. Is it fair for me to say I listen to music approx 73dbz or are my estimates so far off as to be meaningless?

I measured pink noise w/ an app on my phone and my cheap SPL meter, both A weighted, and they clearly get significantly different readings...

I did an estimation of power requirements: At 1.92M from speakers (farthest I'd ever wanna be), with volume of 74+15db SPL (+15db for peaks), sensitivity of 83db, 7db headroom (10db for EQ, 3db extra on top, -3 for 2 speakers, -3 for room gain), power required is 74w.

Why not get an UMIK1 for some 80 bucks right away. Includes calibration file and therefore (almost) error proof SPL (and other) measurements.

Buying an SPL meter and calibrating any mic still costs half the money (provided you already have a mic) and the accuracy is more based on luck than on anything else.

My 2 cents.

 

[Curvature]

You need a separate SPL calibrator if you want the results to be accurate.

 

[Blumlein 88]

Okay maybe this will work well enough. An SPL app on an iPhone is reasonably accurate. Play filtered pink noise over your speakers. 12 db per Octave roll-off below 500 hz and above 2000 hz. Use the iPhone to calibrate your mic. Not lab grade, but not bad and a whole lot better than nothing.

 

[robwpdx]

I have Earthworks M23. I'd like to convey how loud my music is when I listen to music on average but am unsure what the best way to do that is. First the weighting: I'm assuming C or Z weighted is best? Since these weightings do not roll off at bass like A weighting, I assume the average levels will vary based on how bass heavy a track is?

Then there's the measurement part. In REW I'm supposed to calibrate the mic before I use SPL meter feature but to do so I need a mic. Ok, if I could get reliable measurements of volume with a SPL meter to calibrate my mic, why wouldn't I just use the SPL meter instead? I just have a $35 Amazon SPL meter and it's A-weighted. Do I have to buy a C weighted SPL meter and if so which one? This page from REW seems to talk about process of mic calibration w/ SPL meter, but it's unclear to me what weighting the SPL meter is supposed to be. Maybe I'm just too tired or lack reading comprehension.

In this post solderdude seems to say cheap SPL meters are bad for measuring music and only ok for measuring noise levels, but it's unclear to me if they meant the A weighting or the meters just being poorly made.

Listening to music as loud as I want it, $35 A weighted meter measures 66dba and REW w/ M23 calibrated w/ A weighted meter measures 73dbz. Is it fair for me to say I listen to music approx 73dbz or are my estimates so far off as to be meaningless?

I measured pink noise w/ an app on my phone and my cheap SPL meter, both A weighted, and they clearly get significantly different readings...

I did an estimation of power requirements: At 1.92M from speakers (farthest I'd ever wanna be), with volume of 74+15db SPL (+15db for peaks), sensitivity of 83db, 7db headroom (10db for EQ, 3db extra on top, -3 for 2 speakers, -3 for room gain), power required is 74w.

I always suggest if you have an iPhone the https://www.cdc.gov/niosh/topics/noise/app.html as a great but not perfect "calibration" standard. It is FREE.

There are other more expensive methods to calibrate your microphone with your USB mic preamp.

Your key words are calibration traceability. Another method is to ask around in your local technical community for help with a traceable calibration source.

 

[sarumbear]

I have Earthworks M23. I'd like to convey how loud my music is when I listen to music on average but am unsure what the best way to do that is. First the weighting: I'm assuming C or Z weighted is best? Since these weightings do not roll off at bass like A weighting, I assume the average levels will vary based on how bass heavy a track is?

Then there's the measurement part. In REW I'm supposed to calibrate the mic before I use SPL meter feature but to do so I need a mic. Ok, if I could get reliable measurements of volume with a SPL meter to calibrate my mic, why wouldn't I just use the SPL meter instead? I just have a $35 Amazon SPL meter and it's A-weighted. Do I have to buy a C weighted SPL meter and if so which one? This page from REW seems to talk about process of mic calibration w/ SPL meter, but it's unclear to me what weighting the SPL meter is supposed to be. Maybe I'm just too tired or lack reading comprehension.

In this post solderdude seems to say cheap SPL meters are bad for measuring music and only ok for measuring noise levels, but it's unclear to me if they meant the A weighting or the meters just being poorly made.

Listening to music as loud as I want it, $35 A weighted meter measures 66dba and REW w/ M23 calibrated w/ A weighted meter measures 73dbz. Is it fair for me to say I listen to music approx 73dbz or are my estimates so far off as to be meaningless?

I measured pink noise w/ an app on my phone and my cheap SPL meter, both A weighted, and they clearly get significantly different readings...

I did an estimation of power requirements: At 1.92M from speakers (farthest I'd ever wanna be), with volume of 74+15db SPL (+15db for peaks), sensitivity of 83db, 7db headroom (10db for EQ, 3db extra on top, -3 for 2 speakers, -3 for room gain), power required is 74w.

May I point you to my post that touches the subject?

How loud is loud, how to measure it? Is THX calibration bad for your health?

I am an electroacoustics engineer. We are a rare breed. When I got my M.Sc. my class of six were the only ones in UK. I am now retired from engineering and audio is my hobby. You can find more about me on the about page on my profile. The behaviour of the sound (acoustics) and how we hear it...

www.audiosciencereview.com

 

[BoredErica]

Why not get an UMIK1 for some 80 bucks right away. Includes calibration file and therefore (almost) error proof SPL (and other) measurements.

Buying an SPL meter and calibrating any mic still costs half the money (provided you already have a mic) and the accuracy is more based on luck than on anything else.

My 2 cents.

Okay maybe this will work well enough. An SPL app on an iPhone is reasonably accurate. Play filtered pink noise over your speakers. 12 db per Octave roll-off below 500 hz and above 2000 hz. Use the iPhone to calibrate your mic. Not lab grade, but not bad and a whole lot better than nothing.

I always suggest if you have an iPhone the https://www.cdc.gov/niosh/topics/noise/app.html as a great but not perfect "calibration" standard. It is FREE.

There are other more expensive methods to calibrate your microphone with your USB mic preamp.

Your key words are calibration traceability. Another method is to ask around in your local technical community for help with a traceable calibration source.

May I point you to my post that touches the subject?

How loud is loud, how to measure it? Is THX calibration bad for your health?

I am an electroacoustics engineer. We are a rare breed. When I got my M.Sc. my class of six were the only ones in UK. I am now retired from engineering and audio is my hobby. You can find more about me on the about page on my profile. The behaviour of the sound (acoustics) and how we hear it...

www.audiosciencereview.com

You need a separate SPL calibrator if you want the results to be accurate.

Unfortunately I don't own an iphone, just a cheap Samsung a02s I got for $40. REW's SPL meter calibration process involves playing pink noise. My issue w/ my phone is reading changed a ton based on the app I'm using. These should all be A weighted.

$35 SPL meter off Amazon: 56.5db
Sound Meter by Splend Apps: 59db
Sound Meter by ABC Apps: 48.5db
Sound Meter HQPro by Just4Fun Utilities: 16db (???)

These are all highly rated, very popular apps on Android store and the fact that they vary so much from app to app on the same phone seems concerning!

It's cool that iphones seem to have calibrated mics. Do we know which iphones have such capability?

So the question now I guess is, UMIK or $130 SPL meter? If meter, which one on Amazon? It's unfortunate the more expensive m23 has disadvantages vs the cheaper UMIK but such is life.

 

[HarmonicTHD]

Unfortunately I don't own an iphone, just a cheap Samsung a02s I got for $40. REW's SPL meter calibration process involves playing pink noise. My issue w/ my phone is reading changed a ton based on the app I'm using. These should all be A weighted.

$35 SPL meter off Amazon: 56.5db
Sound Meter by Splend Apps: 59db
Sound Meter by ABC Apps: 48.5db
Sound Meter HQPro by Just4Fun Utilities: 16db (???)

These are all highly rated, very popular apps on Android store and the fact that they vary so much from app to app on the same phone seems concerning!

It's cool that iphones seem to have calibrated mics. Do we know which iphones have such capability?

So the question now I guess is, UMIK or $130 SPL meter? If meter, which one on Amazon? It's unfortunate the more expensive m23 has disadvantages vs the cheaper UMIK but such is life.

I think you already answered your question.

 

[Blumlein 88]

How important is exact spl accuracy? The M23 has excellent flat response you can count on. For most audio purposes exact spl isn't so important as relative differences. Using filtered pink noise like I mentioned helps with smartphone mics which are not bad except at high and low frequencies. Even on your Samsung.

Umik 1 is probably a better way to spend money than an spl meter if you are looking for max spl accuracy. I'd find someone with an iPhone to help out for free. You have to know someone who has an iPhone. Once you've calibrated the M23 you are good.

 

[solderdude]

In this post solderdude seems to say cheap SPL meters are bad for measuring music and only ok for measuring noise levels, but it's unclear to me if they meant the A weighting or the meters just being poorly made.

The reason is not the weighting (which is is basically a frequency related sensitivity thing, basically ignoring lows and treble somewhat to a lot, but rather the 'averaging' of it even when set to 'peak' measurements. It usually will show less than what actually happened.
A mic and REW (once calibrated for which you can use such cheaper SPL meters) and recording so you can search for peaks is the best way to measure peak SPL.

 

[Curvature]

A Class 2 calibrator accurate to 0.5dB is probably going to cost $200-300.

A calibrated SPL meter will probably be half that.

 

[BoredErica]

How important is exact spl accuracy? The M23 has excellent flat response you can count on. For most audio purposes exact spl isn't so important as relative differences. Using filtered pink noise like I mentioned helps with smartphone mics which are not bad except at high and low frequencies. Even on your Samsung.

Umik 1 is probably a better way to spend money than an spl meter if you are looking for max spl accuracy. I'd find someone with an iPhone to help out for free. You have to know someone who has an iPhone. Once you've calibrated the M23 you are good.

The reason is not the weighting (which is is basically a frequency related sensitivity thing, basically ignoring lows and treble somewhat to a lot, but rather the 'averaging' of it even when set to 'peak' measurements. It usually will show less than what actually happened.
A mic and REW (once calibrated for which you can use such cheaper SPL meters) and recording so you can search for peaks is the best way to measure peak SPL.

I was originally worried that using UMIK 1 to calibrate M23 itself would have some margin of error, and that just using a UMIK 1 would be better at that point. But if it's not bad as it seems, then I think I'll just borrow a UMIK 1 and calibrate the M23. It beats buying a UMIK 1.