No Strings Attached

no_strings_artKeyboard players prove once again that you can’t believe everything you hear.

By Steve Oppenheimer

Since Jan Hammer’s amazing Minimoog work with the Mahavishnu Orchestra, rock synthesists have shamelessly attempted to emulate the sound achieved by electric lead guitarists. Their success has been notable, if limited: while many aspects of guitar-playing can be replicated on a synth or sampler, not even Hammer pulls off all the guitar tricks in the same manner as a top-flight guitar hero.

The toughest part is real-time integration of rapid chordal and double-stop patterns, picking effects, and riffs into a seamless whole. It’s easier in the studio, of course, but to go beyond straight-ahead leads with an assortment of harmonics-tapping, string-bending, and vibrato effects, you have to invest a lot of time. Nonetheless, a well-rehearsed keyboard player can perform enough guitar-like parts to cover a host of musical situations.

Of course, you don’t have to limit yourself to playing like a guitarist. Many times the point is to fill a similar role, so you can go beyond the guitar’s limitations and add the special strengths inherent in good 10-finger keyboard playing, such as higher-speed licks; larger, more complex chords; and extended note range.

Learning From The Masters
The best way for a keyboard player to sound like a guitarist is to play guitar-even badly. It’s the ideal way to learn how a guitarist approaches a musical situation. Otherwise, you have a lot of watching and listening ahead. Watch guitarists’ hands carefully, and get it feel for how they arpeggiate chord tones within lead lines, when they tend to bend strings, etc. If you want to play a strict guitar emulation, play within the maximum practical range of an electric guitar; depending on the guitar, the range is about four octaves (E2 to E6, or MIDI notes 40 to 88) in standard open turning.

As with emulating other instruments, you I must learn the unique playing conventions guitarists use for various types of music. For instance, jazz guitarists of the old school rarely bend strings, preferring to slide up the fretboard or jump to a different string.

It seems obvious, but it’s worth emphasizing that you should listen to, and practice playing, your favorite guitar parts on keyboard. You don’t need to imitate anybody when playing your music, but every musician can learn from the masters.

Pitch Bend and Vibrato
A guitarist must always finger-bend strings up, not down, due to the design of the instrument. Sometimes players such as the late Roy Buchanan and Jeff Beck get a down-bend effect by bending the string up while muted, then picking it and pulling the string back to normal position. (For a good example, listen to Beck’s “Cause We’ve Ended As Lovers” on Blow by Blow. Not coincidentally, the song is dedicated to Buchanan.) You can do it the same way with the pitch wheel: bend first, then attack the key and ease the wheel back to center position. Guitarists generally accomplish downward bends in either of two ways. The most common method is with the whammy bar but some guitarists occasionally use the machine heads to detune and retune the string

while sustaining a note. (Bluegrass banjo players use this detuning technique, too.)

Although keyboard players have had great success using the pitch wheel for string-bend emulation, it isn’t an ideal controller. If possible, try using a ribbon controller. A touch-sensitive XY pad such as the Spectra Symbol Softstick (tel. 801/972-6995) is even better, but you’ll have to create your own interface circuitry. (We’re planning a DIY project that accomplishes this using the EM MIDI Fader project published in the February 1991 issue. Stay tuned.)

These controllers let your fingers do the work, as with a real guitar, and you aren’t at the mercy of spring tension. They also provide a way to get more realistic vibrato. Jan Hammer is famous for his pitch-wheel vibrato, but apparently he has exceptional hand strength and coordination, so you may find this approach difficult. In addition, some wheels have springs that are too stiff for smooth vibrato effects.

Many keyboard players use LFO-based vibrato (frequency modulation), which often sounds too mechanical to convince a knowledgeable listener. If you randomly modulate the LFO frequency by a very small amount, the results are a bit less mechanical. You also should set the LFO speed to match the tempo and feel of the music. One possibility is to trigger the LFO with a spring-loaded CV pedal and program the patch so the pedal modulates LFO frequency; thus, you can match the LFO frequency to various tempos by ear, “on the fly.” When the pedal is released, the spring returns it to the “up” position, and the LFO frequency is zero (no vibrato). LFO-triggered effects aren’t ideal, but if done well, most listeners accept them.

Chording
A 6-string guitar commonly is tuned (from sixth to first string) to E, A, D, G, B, and E, with the sixth string two octaves below the first string. Alternate tunings are common. (One rockabilly tuning trick, which I first heard used by James Burton, is to tune the sixth string down to D. The deep sound that this produces is worth experimenting with.) You’ll have to use open chord voicings, spread accordingly, which will take a lot of thought until you get used to it. Naturally, you shouldn’t exceed six notes in a chord if you want an accurate emulation.

For strumming effects, roll the notes as if picking them one by one, instead of attacking them all at once. You’ll probably have to use both hands to get the sound of a full chord strummed across six strings. If you’re using a sequencer, you may find it effective to slow the tempo while rolling the chords, then return to normal speed. Jazz guitarists often strum the last three or four strings and slide straight into a melodic lead, ending with finger vibrato. You can emulate this by rapidly rolling your fingers upward, across three notes, and continuing into single-note lines, without string bends.

Oberheim’s Strummer (reviewed in the December 1991 EM) is designed to remap keyboard voicings to sound like a wide variety of guitar voicings. It does a fine job and can save you a lot of work. Strummer emulates upstrokes, downstrokes, and many common guitar-strumming techniques.

Programming
The basic timbre of the unprocessed electric guitar, like most plucked stringed instruments, has a respectable amount of the fundamental, with virtually every harmonic represented. There are so many different guitar sounds, though, that it’s tough to generalize. For an in-depth examination of the topic and a selection of sample synth patches for guitar emulation, read A Synthesist’s Guide to Acoustic Instruments, by Massey, Noyes, and Shklair.

A few tips:
• Use a very fast attack time to get a solid picking sound. Map the synth’s attack time to decrease as key velocity increases so that you get more pick sound (faster attack) when you hit the key with greater velocity. You can accomplish a similar effect if you’re using a sampler and can modulate the sample start-time from velocity. When you want to get an extra-hard picking effect, you can layer a small amount of “pluck” patch-a separate program with very fast attack, almost no sustain, and very fast release-and trigger it with velocity, using a high velocity threshold (low sensitivity).

• Program the synth or loop the sample so that the sound has a longer sustain time than a real guitar string but doesn’t sustain as long as you hold down the key. (Guitarists rely on signal processing for extra sustain; keyboard players can ”have their cake” with sample looping and synth-envelope programming and still use signal processing.) Use a fast release time so you don’t smear the notes in fast passages or when emulating hammer-ons and pull-offs, but make sure the release isn’t so immediate that you get an audible “pop” at the end of the sound.

• Try layering two patches or samples, one of which is the basic guitar sound and the other a feedback sound that has a delayed, long, slow attack. The feedback only enters if you hold the key long enough, then continues to swell as you hold the key. If you use your ear and program the feedback sound to attack as the main guitar sound decays, you can achieve an effect reminiscent of Jimi Hendrix’s feedback at the beginning of “Foxy Lady.”

• One of the difficulties of guitar emulation is that the strings interact, causing sympathetic resonating harmonics. It’s possible to program a poor person’s version of this by such tricks as bringing in a delayed sine wave at the third (or other) harmonic. You can produce much more elaborate and accurate extensions of this idea if you want to dedicate a lot of programming time and multitimbral voices to the task.

• By programming a separate patch with a very fast attack, short sustain, moderately fast release, and simple waveform, you can emulate picked harmonics. Use your ear to tweak the envelopes. You can use velocity cross-switching, pedal-triggered switching, etc., to shift between the regular guitar patch and the harmonics patch. If you can play fast, accurate leaps, you can map the harmonics patch to a separate zone higher up on the keyboard. On an Ensoniq EPS sampler, you can layer the different samples and bring them in with the Patch Select buttons, the left pedal in the double footswitch, or MIDI controller 70. The same holds true of bringing in a “chicken-pickin”’ patch (a variation on the “pluck” patch) or sample.

• A l2-string guitar uses six pairs of strings, with the lowest four pairs tuned in octaves. You can emulate the tuned pairs by using two instruments or two oscillators tuned in octaves, with an extremely short delay between them to account for the time it takes to pick both strings in a pair. The low note sounds first on downstrokes. This also can be accomplished with a sequencer by transposing duplicate notes up an octave and very slightly time-shifting the transposed notes.

Signal Processing
Any effects processors guitarists use are available to keyboardists. Chorusing, flanging, delay, distortion, and reverb are fair game. But synths and samplers output line-level signals far hotter than passive guitar pickups, so if you process your signal with a guitar effects box that expects to see a direct signal from a guitar, remember to pad down the synth’s output level considerably.

Electronic instruments also have a dynamic range far wider than that of an electric guitar. Before you add effects, it’s a good idea to compress the dynamic range to about 6 to 12 dB, as experimentation dictates. It’s best to do this within the patch, but you also can use an outboard compressor. Guitarists often use compressors ahead of their distortion devices, but this is mostly to increase sustain by keeping the signal from decaying too fast, which isn’t as crucial with a properly programmed synth-patch sample.

Before routing the signal to an effects device, roll off the extreme highs, using your synth’s filter or a parametric equalizer. Otherwise, the extraordinary high harmonics generated by a synth will aggravate clipping when put through a distortion device. The distortion box should give you all the highs you need.

A large part of the classic electric-guitar sound is the amp and speaker combination. Sometimes there’s nothing like the real McCoy. Try using an old tube amp with separate channel and master volume pots and a pair of 12-inch speakers. By sending the processed signal to this rig, overdriving the channel circuit, and miking the speakers with a Shure SM58 or similar mic, you can get that classic tube amp sound. Alternatively, you can use a classic amp with a Marshall SE100 speaker emulator (reviewed in the November 1991 issue of EM), or a Tech 21 Sans Amp (reviewed in August 1991). The Sans Amp does a little emulation of its own to produce classic amp tones without an amplifier and is plugged directly into the mixer.

Get Together
It’s a blast to watch a guitarist’s jaw drop when a synthesist comes impressively close to The Sound. Using a synth or sampler to emulate a guitarist also somewhat reduces the need for the genuine article. And with ten fingers and strong chops, you call go beyond mere emulation and pull off licks and chords no guitarist can play. But I still prefer having a hot guitarist around. The biggest thrill conies from challenging each other and combining forces to really rock the house.


EM managing editor Steve O likes working with guitarists. On the other hand, in his touring days, he enjoyed putting bass players out of a job with his left hand.


 (Special thanks to Charles R. Fischer, Rob Rayle, and Kirk Ferris.)

This article is reprinted from the February 1992 issue of Electronic Musician magazine with the permission of its publisher, Penton Media. For more from EM, please visit www.emusician.com.

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