Recording

[steelstring]

Best mic. Placement and distance? I'm using a sm58.

[Earl]

When I mic an acoustic guitar, I place the capsule about 6-8" away from the intersection of the neck and body, pointed inward along the strings toward the sound hole at about a 45° angle.  If you point the mic directly at the sound hole at 90° and get right up on the capsule (which seems instinctive to most players) you get a boomy sound that is hard to EQ and prone to feedback.  I can't tell you home many times I've explained this to performers and set them up properly, only to walk off stage and watch them immediately change it back.  [shrug]

But that is for live sound.  For recording in a more controlled environment you can start there and experiment until you find the sweet spot for your ideal tone.

[jpmist]

Best mic. Placement and distance? I'm using a sm58.

You're not gonna like this but generally, there is no "best".  Plus no one knows what your recording room is like, so there's that. If you have a live room with lots of reflecting surfaces you're gonna get a different tone than with carpets and drapes. Earl above has an excellent recommendation, but I'm guessing that's for live mics.

Having googled the same thing a while back, a lot of sites recommend pointing the mic at the join between the body and neck. I've read anywhere from Earl's 6 inches to 12 - 15". The further away the more room acoustics will be in play.

I think there's a soundfile link to my recordings in my signature to give you an idea.(Opps, not on this forum, https://soundcloud.com/jpmist/bright-reaper-2  have at it!)  I usually have my condensor mic about 14" from the neck join pointed straight at it. It's good to experiment  as a few inches on the bass or treble side of the fretboard will make a lot of difference.  One last piece of non-pro advice is that acoustic guitars boom a lot at about 200mhz and sound muddy, so find a way to reduce that with your equalizer.

Good luck!

[MB]

Steelstring-
You will get MUCH better results with a small diaphram condensor mic. You can find them cheap online in many cases for under a C note.
Power it up with Phantom power and point it at the 12th fret to start and adjust from there while listening in your headphones.
You will find the sweet spot with a bit of experimenting.

[MrHarryReems]

Steelstring-
You will get MUCH better results with a small diaphram condensor mic. You can find them cheap online in many cases for under a C note.
Power it up with Phantom power and point it at the 12th fret to start and adjust from there while listening in your headphones.
You will find the sweet spot with a bit of experimenting.

A pair of SDC's in X/Y stereo is hard to beat.  Personally, I use a single LDC, but that's because my SDC's suck, where I have a great LDC.

[DO18]

As mentioned above; the best place to start with a single mic is at the 12 to 14th fret.  A X/Y setup with two mics will render better results.  Check out the "Polar Pattern" and frequency response for the SM58.  Once you find the sweet spot for the conditions you are playing in the specifications will help you minimize bleed over from the surrounding area and help you get the best you can get from that mic.