[ctm]

For all you technical gurus out there... please explain how you go about doing this.

Unfortunately, when AB'ing cans, it is difficult to equalize sound levels the way you can in a speaker setting (using the trusty Radio Shack or other sound pressure tester module). It's been well documented in carefully conducted listening tests with calibrated equipment, that as little as 1dB difference between one scenario and another (with everything else being equal) is enough to skew the preference to the situation where music is played at the louder level.

I will sit back and enjoy your detailed and thoughtful responses. Happy listening and best regards!

 

[xantus]

well having a cd player that has an a-b repeat mode, and then selecting a short loudish section is usually a good method... you really have to have the ear for it though unless you have an spl meter.

 

[Clown12]

I'd think the easiest way would be to use a multimeter, a 50hz test tone and the published sensitivity of each headphone, although I don't know if you'll get under 1dB doing that. I would have thought the manufacturer's use special dummy head's to do the measurements, like headroom does?

 

[ctm]

sound levels from a single frequency test tone can lead to misleading results. in the two channel speaker setting, most audio guys use pink noise from a favorite audiophile test cd.

the use of a test dummy where the sensors/microphones are placed at the ideal location within the ears of the figure is great but your average guy does not have access to these, unless someone in this forum with lots of headphones has access to such equipment.

anyone else care to share their sound level "equalization" process? is there an spl meter sensitive enough and can be placed at a predetermined "standard distance" away from each diaphragm?

 

[ctm]

I am really interested in hearing if anyone makes it a big part of his or her routine when comparing headphones to make sure that listening levels are the same from one headphone set up to the next.

Doing this is very important when conducting AB (blind or unblind) comparisons. I know lots of local audio club members and audio reviewers in the 2-channel speaker setting go out of their way to equalize listening levels during critical listening. All of them strongly feel that once you are able to rule out unequal sound levels, then you can better hone in on how one piece of gear sounds compared to another.

Please share your clever way(s) of doing this when comparing headphones?

 

[Clown12]

What's so wrong with the sensitivity ratings?

 

[ctm]

There appear to be more than one sensitivity rating standard used by manufacturers. When choosing ideal speakers for ones given set of electronics, for example, one does not usually limit their choices to the sensitivity rating alone. It is a good start and helps to narrow your choices. However, even two speakers with seemingly identical specs can sound very different. Furthermore, sensitivity rating is only one variable... along with impedance (and really the entire impedance curve should be considered, including nominal vs. at what frequency the min and max impedance values occur), output impedance of the amp, amp gain, the type of cable used, connectors, driver/transducer material used, etc.

With all these variables that may impact sonics, one must be able to rule out unequal listening levels from one headphone set-up to another. Otherwise, AB comparison conclusions are that much more subjective.

Where are the R&D engineers, manufacturer reps, gurus, experts, and detail oriented evaluators whose reviews are so widely read? Or, is this simple procedure so logistically prohibitive in the headphone setting that it is just not done?

 

[gorman]

If you have access to a computer with a decent soundcard, you can use replaygain to single files and play them back with supported players (Foobar).

 

[Clown12]

This is the formula I was thinking of:

Volume to change in dB = (sensitivityA - sensitivityB) + 20 * log10( sqrt( impedanceB / 1000) / sqrt( impedanceA / 1000 )))

I think it will give you (without further tests) the same volume from the 2nd headphones as good as a single figure dB will get you.