Recording acoustic guitar/violin/viola

Acoustic Guitar: a great way to mic up a guitar is to place a cardioid, largediaphragm microphone near the sound hole and a smalldiaphragm microphone near the bridge or pointing at the body from below the rear. Find the desired sound by experimenting with the levels of the two microphones in the mix.
Violin, Viola: be sure to use high quality cardioid condenser microphones. Align them at right angles to the sound board, pointing at the f holes from a height of about 6 to 8 feet (1.8 to 2.5 m). Mic the viola in the same way as the violin but from a little further away.