Lacinato ABX is the only cross-platform ABX and shootout blind testing software for audio. It allows double-blind ABX testing of audio files (seeing if you can tell which file is being played), as well as “shootouts” (picking your favorite from a shuffled, anonymized list). Or you can just use it as a convenient way to switch between files (maintaining the current play position, if you like.

Website
Web Service ~ online version
ABX Testing ~ Wikipedia