Originally Posted by: Jahan Honma Then you play just once and you have two separate layers of guitar that are perfectly in synch.

But if you're recording on your computer, why bother? If you're looking for a "perfect" sync, just record one track on your computer, then copy & paste it into a new track.

If you're really looking for a "doubling" guitar sound like bands such as Boston used, record the parts separately on separate tracks. That fact that you're human and will therefore make little discrepancies between each performance is what will give the track that "doubled up" sound. If they are in fact perfect, exact copies of each other, it won't sound "doubled"; it may just sound louder.