[Arny Krueger]

http://ultranalog.com/abxdbt/

"Why do you NEED an ABX/DBT tester?
"Well, it's the ultimate honesty tool.

....

"Software based testers such as PCABX will always put the PC in the signal
path. With a good soundcard in the PC, this is not a bad thing an such, but
it is prohibitive for directly testing stand-alone equipment. For evaluating
codecs or recordings that can be digitally transferred to the PC on the
other hand, it's ideal.

"In short:


a.. PCABX for judging recordings and codecs
b.. A hardware ABX for judging hardware
"Browsing the web I did not find many easy and good implementations. Also,
the ones available are very expensive, with the cheapest one at $600. I
thought I could do better and make a simple design, available for everyone
to reproduce.

Following is a new microcontroller-based design for an ABX Comparator