No problem @Andrew .

And yes the momentary/short term (equivalent of the old ppm/rms dychotomy) measurement by ITU is what Katz now recommand.

 

I agree with the point the author of the T system wants to make. At the end of the day I think the general cadre that Katz defined is good, the numbers inside of it (85,83,79 or 20, 14, 12) are debatable and up to anyone to chose according to what he does. No magic number imo.

 

Read this https://www.digido.com/portfolio-item/level-practices-part-2/

How to calibrate the headphones? Your calibration is being done by Sonarworks. That is the answer.

 

Actually, it looks like the K-Metering by Bob Katz is succeeded by K-Weigthed metering. You don't need to wrap your head around K-Metering except you work in Mastering or Post Production environments that still use it. It was/is also useful if you're working in different studios and they have K-Metering, so you can get to work faster due to the integrated approach and you do not have to bother with loudness a lot. It does not make any sense to use headphones when you have nearfield and farfield monitoring except to check out how it sounds on headphones.

@Agent007
Sonarworks Reference is useful for frequency response but as far as I know it has nothing to do with Metering or does it? It may be helpful to set up headphones but the OP still needs proper Metering.

 

I am still looking for a correct way to use headphones regarding loudness. I know that Sonarworks corrects frequency response of headphones. But I am still dubious about the optimum level I should listen on headphones. Andrew gave a good solution but I don't know how to implement step 2 since I cannot apply "resistive load". Anyways, my headphone model is Beyerdynamic DT990 Pro 250 ohm.

 

This question itself is confusing because the OP is confused as to what K- System is. K-System is a speaker level calibration. It was never intended for headphones. As Bob Katz explains:

It is possible with a special calibrator to measure the SPL of headphones, but there are so many practical issues trying to mix or master on headphones that I don’t think it’s worth the trouble. If you want to get close (but you won’t be exact) you could play calibrated -20 dBFS uncorrelated pink noise on both speakers with your monitor control set to -10 dB to produce a sum of 76 dBC/slow on the speakers, and switch back and forth between the speakers and the headphones. But you must be using a calibrated monitor control for the headphones as well. And when you’re done, where are you? —- No where, because the purpose of the K-System is to judge transient degradation along with examining the position of your monitor control, using your ears. And headphones are deceiving, they exaggerate transients, as do near-field monitors, so it falls apart. https://www.digido.com/ufaqs/calibrating-headphones-k-system/

OP also asks for optimum level for listening on headphones. At a SAFE level.
Experts recommend keeping sound levels at somewhere between 60 and 85 db to minimize the damage your ears are exposed to. If you are listening to music at around 100 decibels, restrict usage at 15 minutes. https://www.headphonesty.com/2017/03/5-ways-to-know-that-your-headphones-are-too-loud/

 

Last edited: Nov 20, 2018

Exactly. It has been told to OP multiple times, but I don't know....Language barrier ? Doesn't seem to understand.
Hopefully your reformulation of things, and the links you've posted to an article earlier about level practice (extract from a Katz article) that had already been given to OP, and the final quote you've kindly provided (he doesn't like quote nor youtube video) will finally make him understand that the matter of loudness measurement (whichever system chosen) is completely disconnected from the question of knowing at which level he should monitor on his headphones (indeed the safest level seems like the safest bet).
Had he read the previous comments and material he would understand why it's a good advice on monitors but fairly irrelevant for headphones, because headphones just aren't proper for monitoring.

 

@Talmi after all of this, there is only one option left:

 

I think measuring the VRMS of amplifiers is usually done with special equipment like function generators. Probably the easiest way to determine the loudness of your headphones would be using a sound level meter (for acoustic measurements).

Be aware that when mixing at 85db with headphones, your ears are in greater danger of damage than they would be when using monitor speakers and listening fatigue will likely set in earlier.

Also keep in mind that the spatial image will never be as clear. Be careful when making left/right and front/back placement decisions.

 

Yep 85 is the highest limit for headphones. Probably a good strategy for going deaf by 40.
Also a sound level meter with headphones ? Sure....Why not. But there will be differences between what it picks up and what OP's ears pick up, so it won't be a very accurate measure. A ballpark....
Cheapest way to do it, and probably as accurate, would be to use your iphone/android phone....There are programs for that.

Be kind to your ears.

 

Last edited: Nov 20, 2018

Nope, all you need is a generated sine wave into input and TrueRMS enabled DMM on the output.
85dB SPL averaged is very high, but most audiophiles listen at that level. I'm usually within 65-72dB ballpark, with peaks reaching around 95dB (but only for few microseconds).