10 TIPS FOR GUITAR MULTIEFFECTS
by Craig Anderton

Everyone's always looking for a better guitar sound in the studio, and while the current infatuation with vintage effects has stolen a bit of the spotlight from guitar multieffects, don't sell these digital processors short. When properly programmed, they can emulate a great many "vintage" timbres, as well as create sounds that are extremely difficult to achieve with analog technology.

As with many other aspects of audio, there is no one "secret" that gives the ultimate sound; great sounds are often assembled, piece by piece. Following are ten tips that are designed to help you put together a better guitar sound using multieffects.

1. DON'T BELIEVE THE INPUT LEVEL METERS

Unintentional digital distortion can be nasty, so minimize any distortion other than what's created intentionally within the multieffects. The input level meters help you avoid input overload, but they may not tell you about the output. For example, a highly resonant filter sound (e.g.,wa) can increase the signal level internally so that even if the original signal doesn't exceed the unit's input headroom, it can nonetheless exceed the available headroom elsewhere (Fig. 1).

Some multieffects meters can monitor the post-processed signal, but this isn't a given. If the distortion starts to "splatter" yet the meters don't indicate overload, try reducing the input level.

Fig. 1: How distortion is generated internally, even if the input meters show that everything's okay.

2. USE PROPER GAIN-STAGING

While we're on the subject of distortion, if a patch uses many effects then there are several level-altering parameters, and these should interact properly-just like gain-staging with a mixer.

Suppose an equalizer follows distortion. The distortion will probably include input and output levels, and the filter will have level boost/cut controls for the selected frequency. As one illustration of gain staging, suppose the output filter boosts the signal at a certain frequency by 6 dB. If the signal coming into the filter already uses up the available headroom, asking it to increase by 6 dB means crunch time. Reducing the distortion output level so that the signal hitting the filter is at least 6 dB below the maximum available headroom lets the filter do its work without distortion.

3. ADD RESONANT PEAKS FOR REALISM

Speakers, pickups, and guitar bodies have anything but a flat response. Much of the characteristic difference between different devices is due to frequency response variations-peaks and dips that form a particular "sonic signature." For example, I analyzed some patches David Torn programmed for a multieffects and found that he likes to add 1 kHz boosts. On the other hand I often add a slight boost around 3.5 kHz (possibly because I played a Fender Tele for quite some time and got used to that biting high end). With 12-strings, I usually cut the low end to get more of a Rickenbacker sound. Parametric EQ is ideal for this type of processing.

4. CUT DELAY FEEDBACK LOOP HIGH FREQUENCIES

Each successive repeat with tape echo and analog delay units has progressively fewer high frequencies, due to analog tape's limited bandwidth (Fig. 2). If your multieffects can reduce high frequencies in the delay line's feedback path, the sound will resemble tape echo rather than straight digital delay.

Fig. 2: Using a high-cut (low pass) filter in a delay's feedback loop gives a more "vintage" sound.

5. A SOLUTION FOR THE TREMOLO-IMPAIRED

If your pre-retro craze multieffects doesn't have a tremolo, check for a stereo autopanner function. This shuttles the signal between the left and right channels at a variable rate (and sometimes with a choice of waveforms, such as square to switch the sound back and forth, or triangle for a smoother sweeping effect).

To use the autopanner for tremolo, simply monitor one channel and turn down the other one. The signal in the remaining channel will fade in and out cyclically, just like a tremolo.

6. INSERT A HIGH-QUALITY PREAMP BEFORE THE MULTIEFFECTS

Trying to squeeze four zillion effects into something the average human can afford is no easy task, so corners must be cut somewhere. Sometimes the input preamp will take the hit, which may result in more noise than desired, or an input impedance low enough to "dull" your guitar's sound. Adding a high quality preamp onboard the guitar, or inline between the guitar and the cord feeding the multieffects, can sometimes give a cleaner, brighter sound.

7. CABINET SIMULATORS ARE COOL, BUT

Many multieffects have speaker simulators, which supposedly recreate the frequency response of a typical guitar speaker in a cabinet. If you're feeding the multieffects output directly into a mixer or PA instead of a guitar amp and this effect is not active, the timbre will often be objectionably buzzy. Inserting the speaker emulator in the signal chain should give a more realistic sound. However, if you go through a guitar amp and the emulator is on, the sound will probably be much duller, and possibly have a thin low end as well-so bypass it.

8. USE A MIDI PEDAL FOR MORE EXPRESSION

A multieffects will generally let you assign at least one parameter per patch to a MIDI continuous controller number. For example, if you set echo feedback to receive continuous controller message 04, and set a MIDI pedal to transmit message 04, then moving the pedal will vary the amount of echo feedback. You can usually scale the response as well, so that moving the pedal from full off to full on creates a change that's less than the maximum amount. This allows greater precision since the pedal covers a narrower range. Scaling can sometimes invert the "sense" of the pedal, so that pressing down creates less of an effect rather than more.

9. MAKE SURE STEREO OUTPUTS DON'T CANCEL

Some cheapo effects, and a large number of "vintage" effects, create stereo with time delay effects by sending the processed signal to one channel, and an out-of-phase version of the processed signal to the other channel. While this can sound pretty dramatic with near-field monitoring, should the two outputs ever collapse to mono (e.g., playback over AM radio), the effect will cancel, leaving only the dry sound. To test for this, plug the stereo outs into a two-channel mono amp or mixer (set the channel pans to center). Start with one channel at normal listening volume, and the second channel down full. Gradually turn up the second channel; if the effect level decreases, then the processed outputs are out of phase. If the effect level increases, all is well.

10. PARALLELING MULTIEFFECTS WITH GUITAR AMPS

One way to enrich a sound is to double a multieffects with an amp, and mix the sounds together. Although you could simply split the guitar through a Y-cord and feed both, here's a way that can work better.

To supplement the multieffects sound with an amp sound, send the multieffects "loop send" (if available) to the amp input. This preserves the way the multieffects input stage alters your guitar. If you'd rather supplement the basic amp sound with a multieffects, feed the amp's loop send to the multieffects signal input to preserve the amp's preamp characteristics.

Well, that covers the 10 tips. Have fun strumming those wires-and remember that the magic word for all guitar multieffects is equalization.