There are many tenor guitar tunings in use: standard CGDA, Irish GDAE, DGBE Chicago tuning. These of course are all derived from common tenor banjo tuning. For backing Irish tunes, I prefer an alternative open tuning.
Tenor Guitar Tuning – CGCG
To accompany Irish tunes, I’ve been using CGCG tuning and putting a capo at the second fret. This gives us a DADA tuning, which is close to DADGAD tuning for a six string guitar and GDAD or ADAD tunings for bouzouki. Anything you can plan on the lowest three strings in DADGAD or the top courses in xDAD tunings for bouzouki will work for DADA tuning on tenor guitar. This includes the bouzouki picking patterns I’ve demonstrated earlier.
If you’re playing with a whistle player with a C whistle or a fiddler who wants to tune down a whole step, you can take the capo off and back the tunes with regular “D” shapes and patterns.
Playing in the key of A is especially nice. You can place an index finger on the highest D string at the second fret and focus on the top three strings – this gives you XAEA as a tuning base. To me, this feels a lot like putting a capo at the 7th fret in DADGAD tuning and playing in A major or minor with “D” shapes and patterns.
Since writing up this stuff is like dancing about architecture, I’ll work on getting some chord diagrams online soon and maybe a video or two.