I can tell if a headphone is craptastic in 15 seconds if I am familiar with the recordings. There are many a time at headphone meets where I simply sit there bored staring at the ceiling because I don't want to be impolite and get up after 15 seconds.

I can tell if a headphone is fantastic within three recordings if I am familiar with the recordings and they are played back on good rigs I am familiar with. Headphones are easy to subjectively assess with experience and a consistent methodology. Amps a little bit harder. DACs most difficult

^This. Marv is honestly being generous with that 15 seconds for some phones. I think for us there are certain sonic characteristics that are just deal breakers immediately.

Thank you for the information, purrin.
And have some questions about your measurement; what is compensation target of your measures?  And want to know about dBSPL(or dBA) of you harmonic distortion analysis. Thanks!

The V2 measurements have absolutely no compensation. The rig was designed to not require any. See this: http://www.changstar.com/index.php/topic,2305.msg63409.html#msg63409

For the most recent measurements, the 0dbFS line = 100db SPL. -10db = 90db SPL. This is very very loud and tends to exaggerate distortion numbers. But I like it this way because it tends to separate the really good stuff from the mediocre stuff. It's more difficult to see differences if we don't push headphones hard.

Can anyone explain what I'm looking at and/or what I should be looking for when I look at a CSD graph?

For example I'm looking at the graph for the PM-2 linked at the bottom of the home page.

Thanks for taking the time to do all this! It's very much appreciated.

Don't take my word for it, but the way I understand it, the csd plots show how fast a transducer settles. In other words, how much residual energy or resonance is left after a tone has been produced.

The interest is that a cleaner plot is the result of a transducer which can reproduce a tone more precisely, avoiding smearing between tones. Timing will also be better, avoiding delay errors.

CSD description: http://www.changstar.com/index.php/topic,120.msg971.html#msg971
Types of driver ringing: http://www.changstar.com/index.php/topic,71.msg219.html#msg219
In terms of detail retrieval: http://www.changstar.com/index.php/topic,593.msg12256.html#msg12256

Marv, Can I ask what is good scale for FR and also for CSD
Do you have recommendations for ARTA and  REW?