Have You Ever Put Your Golden Ears to the Test??

I think that the comparison to wine is appropriate. Just like wine, one's ability to discern differences in audio increases with ones experience. I can't tell the difference between a $10 bottle of wine and the best wine because I don't drink much. When I was in high school, my stereo sounded great compared to my clock radio. Over time, however, as I developed more experience with audio, I found that I needed more. I can now easily tell the difference between equipment and will pay for what I think is better. I won't, however, pay $200 for a bottle of wine because I can't tell the difference.

salut, i'm an easy sale for the proposition that people hear the same sound differenty. people can be predisposed to hear, or ignore, certain sounds. physically, the hearing apparatus of each individual is different and the brains interpertations of the electrical impulses from the ear will certainly differ from person to person. however, where i begin to be sales resistant is when i am told that there is no scientific basis for a difference which people claim to hear, ergo there can be no difference in fact. science is nothing more than a body of extant knowledge and that body grows larger each day. what science can not explain to day they may be able to explain tomorrow. objectivists only see what it to be reaidy seen and do not consider what may be discovered tomorrow which will challenge their opinions. look no further than the various theories and facts regarding evolution - its obvious that the more we know the more we realize how little we knew before, and how little we know about what we will discover in the future. i'm still on the fence regarding evolution as well as audio. all good food for though.

Pick up any Introductory Psychology book. Turn to the chapter on sensation and perception (usually ch. 3 or 4). You will find dozens, if not hundreds, of example of how expectations influence perception, whether visually or auditorially, ranging from the classic of hearing 'Satan rules' or 'Kill your parents' when playing AC/DC Lp's backwards, to the 25 year old study where the sound of the letter 'g' was removed from the word 'legislature' and replaced with the sound of a cough, and nobody could hear the difference. This is one reason why many people WANT to have objective tests of audio equipment; if we expect to hear a difference we will. People who 'hear' the cough as a G aren't lying; it's the way perception works. You can't help it.
There are a number of good comments above about the difficulties inherent in objective double-blind testing. One that I didn't see mentioned (maybe I missed it) was that you shouldn't do it with only one listener. You need a large group of listeners, with each person randomly assigned to one of (at least) two experimental conditions--one group hears component A before component B, the other group hears B before A. Of course, before you can even be in the experiment, you need a hearing test, ESPECIALLY if you are a male above age 40 or so, like (I believe) many of us here are. Not much point in comparing the treble response of two speakers if you can't hear anything above 10K (or whatever)!. You also need standardized source CD's or LP's, volume checks with decibel meters to make sure both components are equaly loud, signal detection theory when analyzing your data to correct for guessing......
Ok, I'm being (somewhat) sarcastic here. My point is that while we could do this, it's TOO MUCH HASSLE AND NO DAMNED FUN AT ALL!! Where's the music in all of this, man?

It has been said by others, but I suspect that everyone's threshold for hearing differences is, well, different. When I upgraded from an old Sony receiver to a Musical Fidelity integrated amp, I heard a massive difference. When I added an Arcam CD player versus an old Magnavox 650, I didn't hear much difference but really didn't listen sided by side. I have since tacked on the new MF DAC (thinking that was why I didn't hear much) but don't really hear much difference between the Arcam direct or through the DAC. While not even single blind, I can flip back and forth and I hear something, or maybe I just think I do (the salesman certainly said he did when I took my Arcam to the store to listen ;^).

My conclusion is that there clearly are some differences I can hear but some that I can't but others probably can. Whether it is their training or hearing damage from sitting in the second row in front of the right speaker bank at a Chicago concert in 1974 that left my ears ringing for days, who knows.

At the end of the day, though, I enjoy the music when I have the time to listen.

For me, listening hard to tell differences creates its own problems. My tinnitus starts raging, and I find that the harder I listen, the less my ears can discern. Over a long term, I can (I think) tell the difference between component A and component B. And, of course, sometimes the differences are dramatic enough to be immediately discernable. But the better the system gets, the more subtle are the improvements. And really appreciating them takes time, for me at least.