I play songs by breaking benjamin and other rock and metal bands which are in low tunings like drop C but i also play in standard when i play for church. I want to get a new acoustic but im unsure what to get my guitar setup to. I only have enough money for one new acoustic and my current one sucks. Its an esteban vintage 2008. My question is what should i get my new guitar setup for? Drop C or standard and if i do get it setup for drop c will it mess something up if i tune it up to standard and back to C constantly. My esteban is so bad it doesnt even have a trus rod so its not like i can get that one setup properly. I think the esteban was made to work with specifically standard but it just sucks and i want to get rid of it. So should i setup my acoustic for c or standard? Just fyi. Sometimes i play in tunings lower than c but not often.
I admire your diversity in the exercise of your craft! From Rock and Metal to church - that's some versatility!
You should have the guitar set up for the lowest tuning you will use regularly. If you have your guitar set up for standard tuning, and you have the relief and action set according to the way most folks like their acoustic guitars (reasonably low) then you will likely have some fret buzz when you drop the tuning.
To understand why this happens, let's look at what the truss rod does on a guitar.
Steel strings exert tension on the neck of the guitar. The higher your tuning (assuming a given string gauge) the more tension will be exerted by the strings. If you could actually tighten all six strings at once you could watch the neck bow as you tightened the tuning gears.
To compensate for that string tension, most steel string guitars are equipped with a truss rod (or two). Tightening the truss rod pulls the neck in the opposite direction than the strings are pulling it - to keep the neck from looking like a boomerang and keep the action playable.
When you drop your tuning - you are relaxing the string tension exerted on the neck and if you don't simultaneously reduce the counter tension of the truss rod, the neck will be pulled flatter by the truss rod or could even end up with a reverse bow. When that happens your strings don't have enough clearance above the frets so you will get fret buzz.
Since it is impractical (and unwise) to make truss rod adjustments during a live performance, you should set up the guitar for the lower tuning. Then you can play buzz free on both the lower and standard tuning. But you will have slightly higher action in standard tuning. You could try a lighter gauge string if this higher action makes it too difficult to cleanly fret some barre chords.
If you have enough time between your rock and metal gigs/practice and church, you could adjust the truss rod between tunings. The first time you adjust the truss rod, make very minor adjustments (no more than 1/4 turn at a time) and give the guitar neck some time to react to the truss rod adjustment before turning it some more. Closely monitor (write it down) how many 1/4 turns it takes so you will know how many to turn in the opposite direction to go to the other tuning and for future reference.
Having said that, I don't think I would want to be continually loosening and tightening the truss rod on any of my guitars. You could end up stripping the threads on the truss rod or perhaps weakening the neck if you did it often enough.
So my best advice is to set up the guitar for the lower tunings you will use and just live with the higher action when playing at church. With your talent, it won't be long before you are getting paid so much in your rock and metal gigs that you can afford a second guitar and have one set up for metal/rock and one set up for church.
Good luck and have fun playing.