Amped Up

May 1, 2007 12:00 PM, By Steve Skinner

One of the best ways to create a unique sound is to use a device in a way other than originally intended: use headphones as a microphone, an aluminum ladder as a percussion instrument, or a resonating filter to play a bass line. Here I'll discuss how to use guitar-amp simulator plug-ins to process vocal, synth, drum, and other nonguitar tracks.

The sounds produced by analog synths aren't as complex as those produced by acoustic instruments; a synth's basic waveforms and envelope shapes are simpler. One way to increase the complexity of analog-synth sounds is to run them through a guitar-amp plugin without using the full-blown distortion of the classic guitar sound. To do that, use a low gain setting and no drive so that there is no audible clipping. Experiment with the speaker simulator turned on and off, because the simulator introduces additional distortion and EQ that may not be desirable.

Back on the Farm

FIG. 1: Line 6 Amp Farm has a good setting for synths and vocals.

Amp Farm is one of my favorite plug-ins for that, and Fig. 1 shows my preferred setting: a 1960 Vox AC30 amp with no speaker. That gives a more complex tone quality to the synth sound. Davide Barbi of IK Multimedia points out that amp simulators at low input levels create additional overtones in the high midrange and introduce nonlinear dynamic responses to the signal. Not only is the basic waveform richer, but the tonal qualities change in complex ways over time (see Web Clip 1).

Amp simulators also work well with vocals. I've recently been working with Ari Gold, a fine singer who likes to build multiple, interweaving backup-vocal parts. I use different forms of compression, EQ, effects, and guitar simulators in the mix to give each part its own character. Two of my favorites are Waves MetaFlanger for flanging and Eventide Quadravox for creating new harmonies (see Web Clip 2). I keep the speaker simulator off and the drive low. This sound is not a distorted one, even though those extra overtones are a form of distortion.

Most guitar-amp simulators are designed to run with a mono input, because most electric guitars have a mono output. Many synths and most backup vocals, however, are stereo. IK Multimedia AmpliTube, IK Multimedia SVX, and Line 6 Amp Farm work most easily with a stereo input (using their multimono mode). Native Instruments Guitar Rig 2 sums a stereo input to mono in its amplifier section. You will therefore have to open two instances of Guitar Rig 2 on two mono aux tracks and bus your stereo signal to it to maintain stereo integrity. (Guitar Rig 2 maintains the stereo integrity of the signal if the amp simulator is not engaged.)

For Added Effect

The effects sections of Guitar Rig 2, AmpliTube, and SVX are also useful in sound design and mixing (Amp Farm has no effects). These effects emulate the cruder electronics of vintage stompboxes, so you get more crunch and character from them than from high-end effects plug-ins. Guitar Rig 2 even has a section of presets for nonguitar use.

My favorite effect in Guitar Rig 2, AmpliTube, and SVX is the wah. You can draw in automation for the wah effect or, in Guitar Rig 2, use any MIDI continuous controller. SVX even has a bass wah. The flanger and chorus effects also have that characteristic guitar-flange sound, which is interesting when applied to other tracks. Between the distortion effects and the amp simulators, you can get just about any kind of distortion you want.

Guitar-amp simulators are usually optimized for the frequency range of a guitar. For synth-bass sounds, I like SVX's Ampeg bass-amp simulator. It creates overtones, as do guitar-amp simulators, and has special compression and EQ algorithms that can add lots of punch (see Web Clip 3). With just the amp and compressor sections active (EQ, speaker, effects, and mic bypassed), SVX sounds good on an entire drum kit.