Measuring sound levels of headphones?

[Meite_U]

I have a practice of measuring the sound levels of my headphones by simply putting the mic of an analog decibel meter against one of the cups. Since professional measurings are taken by using a human head (a model, that is), how reliable or rather unreliable do you figure might my measurements be? Will they perhaps raise too high amounts of decibels, since the ear isn't pressed as closely against the cup?

What do you think?

 

[NiceCans]

I cut a cardboard disc slightly larger than my headphone's earpads, then punched a hole in the center for the db meter.
Holding this tightly against the earpad seals the sound in, and I believe gives a more accurate reading.

 

[tangent]

The tricky thing about this is that sound pressure falls off as the square of the distance, and we're dealing with very small distances here. I can easily see people choosing varying distances from about 1 cm (roughly the distance from the driver to the outer ear) to about 4 cm (adding the distance in to the eardrum). That's enough for 6 dB of variability. Which is correct?

 

[NiceCans]

Quote:

Originally Posted by tangent /img/forum/go_quote.gif The tricky thing about this is that sound pressure falls off as the square of the distance, and we're dealing with very small distances here. I can easily see people choosing varying distances from about 1 cm (roughly the distance from the driver to the outer ear) to about 4 cm (adding the distance in to the eardrum). That's enough for 6 dB of variability. Which is correct?

good question . . . .

The correct one for me, is the one that has me listening at the lower volume.
With hearing (as well as other) safety measures "better safe than sorry" so I choose to err on the side of caution.

 

[Meite_U]

The punched cardboard is an interesting option.

I agree with the remark about safety. I have sensitive ears that will warn me soon enough when a headphones' output goes over the top. But with the high sensitivity of modern headphones, it's amazing what levels of loudness they can produce. When I turn up my amplifier close to volume level 5, I can already measure 100 decibel even when I keep the meter's mic a few inches from the headphones. Some headphones seem to be able to reach some 130+ decibels at full power.