mono sound is a sound of one unique source mixed together to come out of (normally) just one speaker. If you have 2 speakers the it's the same sound that comes out of every one.. . Stereo is a sound that is recorded on 2 channels, a left one and a right one. that means when you hear that sound on a 2 speaker device, you will hear on the left speaker the left channel and on the right speaker the right channel.. You can try this by just come near of one of the speaker and you will realise that the sound is not always the same as the other one.. it may happen that they often talk about stereo music, but in fact nothing is divided so it sounds almost like Mono.. take care ;)