Roger Mcguinn from the Byrds (Mr Tambourine man , 8 miles high , etc) has been playing a 7 string guitar for quite a while.
Now we all know him for those wonderful jingle jangle 12 string rickenbacker sounds
What he has is like a standard 6 string guitar but he has a second g string but tuned up an octave like on a 12 string right next to the regular g string.
so it's just like a 6 string all except for the G string where it is like a 12 string.
It lets you play all kinds of stuff and the mid frequencies just have that extra sparkle and depth. You can do lead licks and it sounds full when strumming. You don't have to change how you play either.
The official model is made by Martin


