The three audio tracks are to the left, with the original at the top. The EQ to the immediate right shows the 24dB/octave lowpass filter response, while the EQ to the far right shows the 24dB/octave highpass filter response (unused EQ sections are grayed out for clarity). The Gloss button is a Sonar X1 feature that adds a little extra sheen to the highs.
Using two mics on an acoustic guitar is a common recording technique that provides a good stereo image, but may also cause phase issues due to the two mics interacting. Stereo miking also doubles the amount of mic preamp noise, and requires more setup time.
On the other hand, recording in mono with a single, high-quality condenser or ribbon mic eliminates phase problems and reduces noise, but loses the stereo image. However, equalization can create a stereo image from a mono signal, resulting in a spacious, big sound that is particularly well suited to solo guitar. Furthermore, you can dedicate your gear budget to a single, high-quality mic, rather than two mics of lesser quality.
To create this virtual-miking perspective, first copy the original, monaural guitar track to two additional tracks. One track will be the “finger noises/high frequencies” track. Solo it, and set its EQ for a highpass filter response with a 24dB/octave slope and frequency around 1kHz. Pan this track right, because if you’re facing a guitarist, the finger and neck noises will be to the listener’s right.
The second copied track is the “guitar body ” track. Solo it, and set its EQ response to lowpass, with the slope to 24dB/octave, and frequency at about 400Hz. Pan this track left, as it provides the guitar body’s “boom.”
While monitoring all three tracks, pan the original track to center and bring up its level. The result should be a big, rich guitar sound with a great stereo image, but we’re not done quite yet.
The balance of the three tracks is crucial, as are the EQ frequencies. Experiment with the EQ settings, and consider trimming the ranges covered by the high and low tracks in the original track. For example, if the body track consists mostly of frequencies below 400Hz, trim frequencies below 400Hz from the original track, as that will increase the separation. Similarly, you might want to trim the highs on the original track in the same range as the finger-noises track. If the image is too wide, simply pan the two copied tracks more to center.
You may be taken aback to hear a stereo guitar with no phase issues. The sound is stronger, more consistent, and the stereo image is rock-solid. Give it a try!
With condenser mics, a small-diaphragm type gives the best transient response—yielding a tight, present sound—while a large-diaphragm mic gives a somewhat warmer vibe. Given only one option for recording acoustic guitars, I’d go for the small-diaphragm condenser. —CA