It is a sad fact in the US that most people enjoy music only when they are doing somthing else; driving, cleaning the house, working on the computer, powerwalking, etc.. Relatively few people can actually sit down just for the purpose of listening to and enjoying music. Probably due to the pressures of "getting stuff done", making money, or even video games and home theater, we've in many ways lost the ability to appreciate music (this goes for many of the arts as well). Perhaps our natural curiosities have been replaced by any number of things seemingly designed to drain away our imaginations - the new millenium has not brought out truly good music to the masses, and even hollywood is in a rut with mindless remakes of perfectly good classics. There are exceptions of course, but turn on your TV and you'll see what I mean.
The concept of fidelity is alien to many stereo owners, and with the proliferation of computers, iPods and compressed audio, it's no wonder that many people do not know what a live orchestra sounds like, or what a rock band really sounds like. It may suprise you to find that most people have no idea of what instruments they are hearing when they are played. As a consequence, most folks will say that they have no idea if one stereo system sounds better than another. If you or someone you know would like to get a better understanding of stereo sound reproduction and the nature of hearing, then this I hope this article will be a good start.
The first thing to do is to relax. Go to the room where your stereo is and sit in the place where you will be listening (it is assumed that your speakers are set up so that they are equidistant from your listening position). Get comfortable and clear your head, that is; stop thinking for a little while. Don't play any music yet, just sit and listen to what's going on around you. What do you hear? How many different sounds can you count? Can you hear the refridgerator running? The clock on the mantle? Your neighbor three doors down mowing his lawn? Just listen to the ambience around you, close your eyes and locate where those ambient sounds are coming from - keep your eyes closed and point at the sound source. Now, open your eyes. Are you pointing at the source of the sound? Most likely you are. The ability to locate the source of a sound is one of our primal human survival tools, and your stereo was designed to exploit this tool. Repeat this excercise, but this time, take a guess at how far away these sounds are from you. Did you guess reasonably well? Most likely you did. See, the room that you're in is of a certain size and whether you are conciously aware of it or not, your brain has already processed the room dimensoins and adjusted your ears to suit that envioronment. Sounds reflecting off the walls, floors & ceiling not only give good clues to the direction of a sound source, but also give a sense of distance due to the arrival time of multiple sound waves to your ears. This is called the Haas Effect. Don't worry, you won't need to memorize this.
Now, play some music. Keep your head clear and close your eyes again. Just listen. Where are you? Are you still in the same room, or has the room changed? A well set up stereo can put the musicians in your room or transport you to the room where the musicians are playing depending on the recording. Listen some more with your eyes closed - can you "see" where your speakers are or have they dissappeared? Can you "see" how big your room is? Does it sound wide like the sound is coming from beyond the walls? How far back does the sound go - in front of the speakers, behind the speakers or both? At this point, there are no right or wrong answers, this is just an excercise to use your ears as eyes. Continue listening to the music, but this time listen to only one instrument. Can you find it's location within the context of the recording? Can you find the instrument's location within your room? Go ahead, use your imagination a little.
Stereophonic sound reproduction has two major objectives: 1) Reproduce sound realisticlly by 2) reproducing the spatial cues of those sounds. What this means is that a stereo system aims to achieve the convincing illusion of a space and specific points within that space. This is called imaging. Listen to your system again - let's try vocals this time. Does the singer appear as a point directly in front of you, or does the singer appear to be all around you? Close your eyes - can you point to the singer? How far away is the singer? Does the singer sound like a person singing in your room or another room or does the singer sound as if their mouth is 5' wide? Obviously, a singer should sound like a human being, so this is an easy way to determine if your stereo is imaging correctly and, as an added benefit, you get to exercise your listening skills.
There is more to sound and listening than just spatial qualities; there are also pitch, timbre, harmonics, rhythm and timing, dynamics, and a number of other qualities. This article is just to get you started on developing your listening skills even if you can't tell the difference between a chello and a contra bass. Ear training, as it is called, takes time and practice, but it opens up a whole new world of sound. You'll suddenly notice little nuances in music that you never knew were there. Songs that you've heard a million times before take on new meaning and greater value. This is part of the reward in assembling a good audio system, and even more so, gaining a greater appreciation for music. Have fun!