by Craig Anderton
Since the dawn of time, with a very few exceptions electric guitar outputs have been mono. This made sense for when the main purpose of guitar players (aside from picking up members of the opposite sex) was to take an amp to a gig and plug in to it. But with more guitar players opting for stereo in the studio, and sometimes even for live use, it’s natural to want to turn that mono output into something with a wider soundstage.
So, here are six tips (one for each string, of course) about how to obtain stereo from mono guitars. But first, our most important tip: Don’t automatically assume a guitar part needs to be stereo; sometimes a focused, mono guitar part will contribute more to a mix than stereo. On occasion, I even end up converting the output from a stereo effect back into mono because it ends up making a major improvement.
1 EFFECTS THAT SYNTHESIZE STEREO
Reverb, chorusing, stereo delay, and other effects can often synthesize a stereo field from a mono input. This is particularly effective with reverb, as the dry guitar maintains its mono focus while reverb billows around it in stereo. Some delays offer choices for handling stereo—like ping-pong delay, where each delay bounces between the left and right channels, LCR (left/center/right, with three separate taps for left, center, and right delay times), and the ability to set different delay sounds for the two channels.
I wrote an article for Harmony Central regarding “virtual miking” for acoustic guitar parts (particularly nylon string guitar), which uses EQ to split a mono guitar part into highs on the right, lows on the left, and the rest in between. As this needs only one mic there are no phase cancellation issues, yet you still hear a stereo image. Another EQ-based option uses a stereo graphic EQ plug-in. In one channel, set every other band to full cut and the remaining bands to full boost; in the other channel, set the same bands oppositely (Fig. 1). For a less drastic effect, don’t cut/boost as much (e.g., try -6dB and +6dB respectively).
Fig. 1: A graphic equalizer plug-in can provide pseudo-stereo effects.
3 DOUBLE DOWN ON THE CABS
With hardware amps, split the guitar into two separate cabinets and mic them separately to create two channels. Doing so “live” will usually create leakage issues unless you have two isolated spaces, but re-amping takes care of that problem because you can create the other channel during mixdown. Remember to align the two tracks so that they don’t go out of phase with each other.
4 CREATE A VIRTUAL ROOM
Speaking of amp sims, many of them include “virtual rooms” (Fig. 2) with a choice of virtual mics and mic placements. These can produce a sophisticated stereo field, and are great for experimentation.
Fig. 2: MOTU’s Digital Performer includes several guitar-oriented effects, as well as virtual rooms for both guitar and bass with multiple miking options and cabinets.
5 PARALLEL PROGRAM PATHS
Amp sims often create stereo paths from a mono input. For example IK’s AmpliTube has several stereo routing options, while Native Instruments’ Guitar Rig includes a “split mix” module that divides a mono path into stereo. You can then insert amps and effects as desired into each path, and at the splitter’s output, set the balance between them and pan them in the stereo field (Fig. 3).
Fig. 3: Although you can use Guitar Rig to create mono effects, its signal path is inherently stereo. This makes it easy to convert mono sounds to stereo.
My favorite plug-in for this is the old standby Sonitus fx: Delay, because it has crossfeed as well as feedback parameters. Crossfeed can help create a more complex sound by sending some of one channel’s signal into the other (Fig. 4).
Fig. 4: The ancient Sonitus fx: Delay is excellent for create a stereo spread from a mono input. Here it’s used as part of a custom FX chain in Cakewalk Sonar to add width to guitar parts.
However, there are plenty of other options. One is to duplicate a mono guitar track, then process the copy through about 15-40 ms of delay sound only (no dry). Pan the two tracks oppositely for a wide stereo image. Make sure you check the mix in mono; if the guitar sounds thinner, re-adjust the delay setting until the sound regains its fullness.
Craig Anderton is Editor Emeritus of Harmony Central. He has played on, mixed, or produced over 20 major label releases (as well as mastered over a hundred tracks for various musicians), and written over a thousand articles for magazines like Guitar Player, Keyboard, Sound on Sound (UK), and Sound + Recording (Germany). He has also lectured on technology and the arts in 38 states, 10 countries, and three languages.