Intrigued, I've done some research into this.
Most studio recordings are really multi-channel mono recordings, in which the producer 'places' the audio signal from each channel somewhere between hard left and hard right using the pan control on the mixing console. Each instrument or voice is recorded very close to the source, eliminating any room effects. The relative content, left vs. right, is a production decision, so listening with the left earphone in your left ear and the right in your right reproduces the environment the producer was trying to create.
So, in effect, you could end up hearing things the opposite way round.
Yes, thanks Tom. That seems to explain why you don't get that stereo effect anymore, where the sound moves from speaker to speaker - some of the Beatles songs have it. I rather like that.
