AlexM wrote: > Hi Gary, > > Yes, Coax and optical outputs are active at the same time and you can > compare them. It requires a reboot to swap between SPDIF/COAX out and > USB out. > > I must admit I've never looked at the protocols involved in conducting > such a test. I assume that the test subject must not know which is > which, and I guess a single test subject (me) isn't going to be proving > much anyway. To be honest, I'm not sure I would go to the trouble of > doing a Double blind ABX test as I am already clear about what I prefer > and am not out to prove there is a statistically valid subjective > difference. More relevant to this thread is doing some comparative > measurement to see if there is anything that is measurable using > something very similar to Archimango's test rig. > > Anyway, I'll have a look at how one might do an ABX out of curiosity - > any good links relevant to my sort of config?. > > Cheers, > Alex
Alex, yes, a double blind test would actually require that you didn't know which output was selected (while listening) and that the person that is flipping the switch on your DAC either not know (probably impossible) or at least is not present in the room while you are listening (so as to not give off some non-verbal cue as to which input has been selected). Actually, even as a single subject, you can learn a lot with such a test. As a simple test, you would want to do several trials (let's say 10 to 20), where you listen to as long a bit of music as you want (could be seconds, minutes, or weeks for that matter) and note whether you think this is the toslink or coax. After you're done with all your trials, the other party (one flipping the DAC input switch) will then provide you with the list showing the actual input you were listening to at each point. Then you compare your "guess" vs actual and you have a n/N hit rate of how many of the trials you picked the correct input. If you pick enough correctly, then the difference is truly detectible to you. If you don't pick enough correctly, then this indicates that when you *thought* you heard a difference you didn't really hear this and other forces were at work. And believe me, this can happen in many contexts other than music/equipment, even with sophisticated experts making comparisons within their area of expertise. http://en.wikipedia.org/wiki/Blind_experiment p.s. And I wasn't suggesting that you have to do a test of this difference to satisfy me or anyone else. I was just pointing out that if you wanted to do one, you likely could. But such a test is always welcome because this does exclude the possible interpretation that you simply *think* you hear a difference versus your ability to hear a difference under a more controlled environment. ------------------------------------------------------------------------ garym's Profile: http://forums.slimdevices.com/member.php?userid=17325 View this thread: http://forums.slimdevices.com/showthread.php?t=97950 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
