Some engineers take DI on acoustic guitar as a matter of course, but its sound is quite unlike a conventionally miked instrument. Getting the two sounds to gel is possible when you have the right tools.
Some studio engineers consider DI’d acoustic guitar unusable on a studio recording, often based on experiences of poor-sounding pickups that seem to make the instrument sound like it’s strung with rubber bands! Certainly earlier piezo and magnetic systems could lend an unpleasant ‘quack’ to sounds whose only real usefulness was on stage where the choice was “hear it, or don’t”. More recent pickup technology has meant that the signal from these systems now has uses beyond just feeding a guitar tuner. While the sound is unmistakably transduced, with modern processing the plugged-in sound has uses that can elevate it up to mix-worthiness in some cases
What Are We Up Against?
The sound of pickup systems for acoustic instruments certainly has a sound of its own, and those traits are easier to counter when we know what we’re listening for. Often the transient profile of the pickup will be more prominent than a mic signal owing to the body being a quicker medium than the air. The tonal balance can also be badly skewed by placement of the transducer itself owing to errant nodes on the body.
What Can Be Achieved?
While no-one is pretending that an acoustic guitar’s DI can seriously rival the sound in the room, the sound can have some uses. Mic sounds too thin? Sometimes the DI with judicious use of low pass filtering can fill out the low end while no-one’s looking. Need some stereo interest on a mono-miked sound? On the understanding that the mic signal ‘leads’ the ear into perceiving a real sound, a carefully processed DI can fill out the picture in a mix with surprisingly good results. On live recordings, if there is a mic signal available, its stage and monitor spill usually means that the DI wins by default.
Eventide Split EQ
The new EQ from Eventide offers functionality that lends itself perfectly to the challenge of bringing DI’d acoustic instrument signals into a mix. Using separate EQ techniques for transient and tonal elements of the signal allows the engineer to sit the DI behind or alongside a mic signal to fix bogus, brittle or plasticky direct sounds once and for all. In the video watch how we take a DI and use it to blend with an existing mic signal to augment the stereo field.
DI’s Can Be Useful
Thanks to modern tools such as Eventide Split EQ, the humble DI (among other ‘problem’ sources) may have found its way onto more records than would have been possible. The only thing left to do now is for the engineer to remember to actually record it…