ABX testing is a methodology for comparing two devices or systems. In this case we're testing two audio clips of the same solo acoustic guitar performance. One clip was recorded with $150 preamp, one with a $1500 preamp.
foobar2000 is an audio player for Windows that includes an ABX utility. This utility makes it easy to compare two clips in a double blind test. The ABX utility maintains score and computes the statistics for the comparison series.
Please visit http://www.homebrewedmusic.com/2009/0... where you can download the clips used in this video. You will also find links to other test clips and more information about ABX testing, along with other posts related to home recording of acoustic guitar.