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Is there a way I can ACCURATELY measure how loud my music is, to protect my hearing, WITHOUT needing to buy expensive test equipment?

^^^ Make sure the meter can read the audio band, or at least as high as you want to test. Many cheap meters, and even some expensive ones, target AC power lines and are limited to ~100 Hz or so.
 
Most SPL meters have a short (sometimes long) shield around the mic that makes it more directional to limit the capture to a small'ish area (volume). Unlike many measurement mics, which typically have broad response (omni's are commonly used), an SPL meter is generally used to measure a specific target area. It should work fine for headphones, at least it did for me way back when. At the time, I compared my approach to a head (bust) mounted unit the university's audiology lab had, and for levels it was basically an exact match. Frequency response differed somewhat since my rig measured essentially "flat" response (I did not have an HTF* model).

FWIWFM - Don

* HTF = Head-related Transfer Function, see e.g. https://en.wikipedia.org/wiki/Head-related_transfer_function

@Quinton595 : You should be able to edit the title in your first post, or click on the "Report" link at the lower left of that post and ask a moderator to do it, and add the word "headphone" in there for future reference.
 
Information about it is on the CDC.gov site!

Oh COOL, thank you for sharing!

I'd be careful using the OSHA guidelines for music listening. If you read the actual OSHA docs, their levels are meant to retain the ability to converse as we get older, not to discern fine musical nuances and such over a wide range of dynamics and frequencies. They are very much an upper bound for those who want to retain our hearing through the years.

Yes, I'm with you 100%. I just want to take some measurements so I can establish an absolute upper limit, but, like you said, it's an upper bound, not a recommended listening level. I'm not doing this so I can then listen at the absolute loudest volume I can -- I just want to know what never to exceed, even though I will regularly listen well, well below it.

Like, even though 85 db is the OSHA limit, I'm going to try and never exceed 75, if I can help it.

This wouldn't be perfect (and it won't give you A-weighting*) but it you have a sensitivity spec, I'd get an analog multimeter to measure the voltage. (Digital meters are pretty-useless with constantly-changing audio whereas the inertial of the analog meter tends to smooth-out the reading, giving reasonable-useable moving average.) A short-term average is what you want anyway. (Make sure to get a meter that can read below 1VAC.)

You'd need to rig-up an adapter... Maybe a Y-splitter so you can plug-in your headphones at the same time. (Getting a connection to your meter is probably the hardest part.)

You can set-up a spreadsheet to make the calculations. (You may have to research the formulas.) If the sensitivity is given in mW, the first thing is to convert that to voltage (which depends on the impedance). That's just a one-time calculation.

Then when you calculate dB, you're going to be calculating the dB difference, so the last thing in your formula will be addition.

Here's an easy made-up example:
Let's say your headphones are rated for 90dB at 1V. So 1V is your reference. You may know that a voltage factor of two is a 6dB difference so I'll show the SPL calculation at 2V.

If you are measuring 2V, your calculation would be 20 x log(2/1) = 6dB. 9+6 = 96dB SPL

...Or if you read 0.5V, you'd calculate -6dB, and adding -6 to 90 gives 84dB SPL.




* Without A-weighting, bass will read "louder" than it actually is. ...Highs will also read louder than they are, but with regular program material the highs are weaker than bass & midrange so that won't mess-up your readings.

Thank you for taking the time to explain all this! I may end up doing this approach one day, just for fun, to corroborate the readings I get from a sound meter.

Most SPL meters have a short (sometimes long) shield around the mic that makes it more directional to limit the capture to a small'ish area (volume). Unlike many measurement mics, which typically have broad response (omni's are commonly used), an SPL meter is generally used to measure a specific target area. It should work fine for headphones, at least it did for me way back when. At the time, I compared my approach to a head (bust) mounted unit the university's audiology lab had, and for levels it was basically an exact match. Frequency response differed somewhat since my rig measured essentially "flat" response (I did not have an HTF* model).

FWIWFM - Don

* HTF = Head-related Transfer Function, see e.g. https://en.wikipedia.org/wiki/Head-related_transfer_function

@Quinton595 : You should be able to edit the title in your first post, or click on the "Report" link at the lower left of that post and ask a moderator to do it, and add the word "headphone" in there for future reference.

Good to know! It seems this really is as simple a matter as using a regular Sound Meter, which I wasn't expecting. I will probably end up making a test board as was illustrated in a previous post.

I basically consider my question answered at this point, thank you to all who commented, I greatly appreciate your help!
 
I have an iPhone and AirPods Pro 2 (in ear).

My Apple Watch has a built in SPL meter app that alerts if the volume of external sounds OR my AirPods are too loud.

I assume this will not work with non Apple headphones but I’m not sure.
 

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