It is fascinating how musicians like the late Michael O’Domhnaill, Luka Bloom, Paul McSherry or even rocker Jimmy Paige and folk icon Neil Young made guitar sound THAT way. I did some research and came across this tuning called DADGAD which is also referred to as modal tuning.
It follows the art of how bagpipes are tuned with the drones. Unlike the standard EADGBE, DADGAD tuning creates that warmth, ethereal sound that is distinctive in players of Celtic music.
Youtube has shown me a lot of ways to tune the guitar in the DADGAD and I chose this video which I think is more helpful in explaining the procedure. If you are an expert or a newbie, you might try considering this kind of tuning as an alternative, to create a distinct sound of your own. Check this one out by Jamie Roberts.
Following our DADGAD tutorial is a musician known for this : Paul McSherry.
According to his Myspace:
Originally from Finaghy road north in West Belfast, I now reside in Magherafelt, Co. Derry and have been playing the guitar (DADGAD tuning) from the age of 14.
At present, I am Head of Technology and Design in Drumcree College, Portadown, Co. Armagh.
Check out his video playing here: http://www.paulmcsherry.com/video/index.html