If you have some tools, I'll show you when I'm on PC. Kinda hard to put formulas on iPod.

Sent from an iPod touch with TapaTalk... Autocorrect may alter the meaning of this message

EDIT:

OK, ready for your physics lesson? What you'll need to measure the volume of your headphones without an SPL meter is the following:

- A volt-meter and aux cable (or a way to estimate voltage)
- Sensitivity (for the given frequency range you want to measure) of the headphones
- Impedance (for the given frequency range you want to measure) of the headphones

Now, for some formulas that will be used. They are all electrical

- v = ir
- r = (1/r1) + (1/r1) + ... + (1/rn) iff parallel such that for headphones, r1 = r2 = rn = rm. Since there are only two earpieces, there is only an r1 and r2 so r = 2/rm. rm = impedance of the headphones though, so we get: r = 2 / imp
- i = vr
- p = iv
- spl = ps where s = sensitivity
- db = 20 log(spl) such that the log has a base of 10.

First, find the voltage of the device you are using. Get your aux cable and plug it in. Place the volt meter the the first terminal and third terminal. Measure the voltage, you have found your v. If you have no volt meter, I found through some trial and error that the voltage of the iPod touch is approximately 1.11 * (volume)^2 such that the volume = the percentage of total volume in decimal form (volume% / 100).

Find your r.

r = 2 / impedance

Find your i

i = vr

Find your p

p = iv = v^2 r

Find your spl level.

spl = sensitivity * p

Convert to dB

dB = 20 log(spl) You can also use this converter: http://www.sengpielaudio.com/calculator-soundlevel.htm

And you're done...

Back on topic now, the A161p