Here is the most common mistake made in home studios and live acoustic gigs: pointing a microphone directly at the acoustic guitar's soundhole. The soundhole is an acoustic cavity resonator pumping out a massive, boomy blast of low-mid energy between 100 Hz and 200 Hz. Put a mic there, and your track will sound like mud.

Here is how professional engineers capture acoustic guitars, violins, cellos, and stringed instruments with sparkling clarity and zero mud.

1. The Gold Standard: The 12th-Fret Technique

To capture the natural balance of string pick attack, fret articulation, and woody body resonance:

  • Placement: Place the microphone 8 to 12 inches away from the guitar.
  • Aim Point: Aim the capsule directly at the 12th Fret (where the guitar neck joins the body).
  • Angle: Tilt the mic slightly ($15^circ$) toward the bridge.
  • The Result: You get crisp string definition and pleasant body warmth without any of the boomy resonant blast from the soundhole.

2. Transducer Choices: SDC vs. LDC vs. Ribbon

  • Small Diaphragm Condensers (SDC - e.g. Neumann KM184, Rode NT5): The #1 choice for acoustic guitars. The ultra-light diaphragm captures lightning-fast fingerpicking transients, pick clicks, and top-end air (10-20 kHz) with surgical precision.
  • Large Diaphragm Condensers (LDC - e.g. AKG C414, Audio-Technica AT4050): Great for solo acoustic guitar and cello where you want a wider, warmer low-end body.
  • Ribbon Microphones (e.g. Royer R-10 / R-121, Coles 4038): The secret weapon for violins, mandolins, and banjos. These instruments can sound piercing and shrill through condenser mics. A ribbon smooths out harsh bow friction and delivers a warm, woody, organic tone.

3. Quick Stereo Arrays for Acoustic Guitar

  • The Spaced Pair (A/B): Put one SDC at the 12th fret (for neck articulation) and one LDC near the lower bout behind the bridge (for body warmth). Pan left and right for a wide, radio-ready acoustic guitar sound.
  • The XY Pair (90°): Place two matched SDCs with their capsule tips nearly touching at a $90^circ$ angle at the 12th fret for 100% mono compatibility with zero phase cancellation.

(Analyze acoustic instrument frequency overtones with our RTA Spectrogram).