I am trying to cover Ashes in the fall- Rage, I can nail the vocals and have got the guitar part down pretty well, but still need to do some work and tweak my gt-8 to get the effects right.

I am going to the guitar and vocals seperatly then try to combine them or overlap them so it's the best of both ends of it.

Do I need some sort of software to overlap audio files?

Audacity, its free and works great
If The Sun Refused To Shine
I Would Still Be Loving You
Mountains Crumble To The Sea
There Would Still Be You And Me

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