So, what is the ideal string action for an acoustic guitar?
There are as many opinions about this controversial subject as there are about the meaning of life.
The conventional recommendation is that string action (the distance from the top of the fret to the bottom of the string, when measured at the twelfth fret) fall within a range of 3/32" to 7/64" for the bass 'E' string, and 1/16" to 5/64" for the treble 'e' string. And, that the neck have 'relief' (a slight arc) of .004-.010 at the 6th fret when a capo is applied at the 1st fret, and the bass E string is fretted at the 12th fret.
Sounds pretty simple, right?
However, there are numerous variables which can and will affect this wisdom. For example, Humidity and/or dryness; wear and/or grooves at the nut and saddle; depth of nut grooves in relation to fingerboard; saddle contour; tension placed on the top, which may cause it to warp; other structural problems such as loose bracing, nut or bridge; something as simple as changing string gauge; neck relief (whew, this is a controversial subject); and unlevel frets, to name a few things that can keep the debate alive.
Why is string action so important? Because it affects playability. If the action is too high, fretting the strings is uncomfortable, and if the action is too low, strings buzz.
Although many experts offer specific recommendations for adjusting string action, it is really left to understanding an individual player's technique that dictates how a guitar should be set up.
Well, Larry Cragg, a Northern California luthier, who has vast experience setting up guitars has a different view. He adjusts the guitar neck so that it is perfectly straight after he makes a few preliminary changes (if necessary) like replacing plastic bridge pins and saddles with bone and/or ebony. Some, who have studied guitar setup, may view this as wrong, but if asked, Cragg will smile and say, "You know, the book says that there's got to be neck relief. That's all bullshit!"
Have you ever gone into a guitar store and taken a good look at the string action on the various models you've played? I have, and I'm continually mystified by how the string action setup varies so greatly, even with high-end brands. One can only assume that setup at the factory is un-precise so that the music store tech can adjust to the desire of the buyer. But, if the setup is un-precise, wouldn't that discourage a player when trying out the guitar? While working at a local music store, I was constantly checking nut groove depth and adjusting saddle contour and height to make guitars more playable, while keeping them within the recommended action range.
And, there is also the occasion when a player wants their acoustic guitar to play like an electric. Nice idea, but not very realistic. They are two separate and different instruments.