Went to http://www.audiocheck.net/soundtestsaudiotesttones_index.php, and plugged my ESS Mark 1's into my computer, using an adapter. Here's the results.
Frequency Response tests; from 10Hz to 200Hz = 50 Hz; from 22KHz to 8KHz = 14KHz.
Dynamic Range; 42 Db below scale.
Bass Shaker: No rattle
Driver Matching = Equally matched on left and right channels.
Wiring: Left and right appear just fine.
Polarity Center: feels lik it is in between my eyes or in front of me.
Polarity Twisted: Feels like it is all over my head or at the base of my neck.
Binaural Test: Wooden door knock actually startled me, and seemed to come from over my right shoulder, then over my left shoulder. It did sound like a real wooden door.
Favorite Music: I usually use an iPod from 2007 to listen to various rock and country songs, and every once in a while some classical. It sounds pretty darn good, even if it is a digital format (I listen to records on decent speakers when at home).