I had a question about guitar tuning. I like playing songs by Goo Goo Dolls and Nick Drake, and most of their songs are in alternate tunings like Open C, ‘B D D D D D’, or ‘D A E A E E’ to name a few.
Is it harmful to my guitar, or will it make it harder for my guitar to “stay in tune” if I keep tuning between these alternate tunings and Standard tuning? “C G C F G E” for example is quite a big difference to Standard Tuning when compared to something more simple like Drop D.
In short, no, you’ll be fine (as long as you’re not tuning up a heap and putting crazy tension on your guitar). Some of the finest fingerstyle player I know (Don Ross, Thomas Leeb, Jon Gomm etc) hardly play two consecutive songs in the same tuning. You might find strings don’t last as long!
Alternate tunings won’t hurt your guitar but if you detune & retune the strings too often you might need to replace them more frequently.
Some time ago I played around with alternate tunings and found that tuning the low E string down to C# or C made it just too flappy to be comfortable to play. So you might want to check out strings designed for lower tunings, or buy single strings depending on the tuning(s) you want to play in.
Open C is a very low tuning (lower string tension than standard). You may notice that your strings “buzz” when you play if you take a guitar that is set up for standard tuning and tune it down to open C. The fix for this would be either thicker strings (which will increase the tension) or a small truss rod adjustment (to compensate for the lower string tension).
When I tune my acoustic down to open D (D A D F# A D, thickest to thinnest string), I get a slight buzz on my high e string due to the neck angle change from the lower string tension. This would be even worse if I tuned another full-step down to open C. A small truss rod adjustment would fix this, but them the action would be a little higher when I return to standard tuning.
In summary, tuning up/down from standard won’t hurt your guitar, but you may need to adjust your truss rod so it plays well at the lower string tension.
The harmful part of increasing the string diameter is that if it does not quite fit in the nut slot, then you can crack the nut if you tighten it down. The solution is the get the slot widened a bit to fit the diameter string you want to use. At a minimum, a tight slot will not let the string slide and tuning will be difficult with the string sticking.