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Moog Guitar

Electric guitar-filtering-infinite sustain
Published March 2009
By Paul White

As instruments go, the electric guitar is a pretty established format, but if anyone can change that, Moog can...

Moog Guitar

Over the past few decades we've seen various innovations that have attempted to drag guitar players kicking and screaming in new directions. These have included pitch‑tracking guitar synths, E‑bows, Gizmos and Sustainiacs to give us endless sustain and, more recently, the HRM (Harmonic Restructure Modelling) of Roland's VG guitar range, which takes the existing harmonics of a guitar note, then changes the levels and envelopes of those harmonics to create new sounds.

The systems best accepted by guitarists have been those that maintained the feel and controllability of the guitar rather than trying to turn it into a trigger for samples, so what could Moog, a hardcore synth company, have to offer the guitarist, other than a chance to deepen their overdraft? As it happens, quite a lot, as designer Paul Vo knows a great deal about both guitar players and instrument design. His concept was to produce a guitar that incorporated Moog's classic diode ladder filter circuitry plus the ability to sustain notes indefinitely. Alternatively, notes can also be made to decay more quickly than normal, to produce a more percussive effect.

The Heart Of The Matter

Just slightly more electronics inside than the average guitar. This lot, plus the special pickups and the Foot Pedal Controller, is what makes the Moog Guitar tick — or, rather, sustain indefinitely and that sort of thing.Just slightly more electronics inside than the average guitar. This lot, plus the special pickups and the Foot Pedal Controller, is what makes the Moog Guitar tick — or, rather, sustain indefinitely and that sort of thing.

Any worthwhile experimental guitar project has to start out with a good guitar as its basis, so Paul Vo settled on a fairly traditional but visually striking double‑cutaway, set‑neck instrument weighing in at around 8lbs. This is built for Moog by Zion guitars. Bolting a system such as this onto an off‑the shelf guitar simply wouldn't be practical, as the pickups are very special and there are enough electronics inside the guitar to challenge Skynet for world domination.

The bodies are made either from swamp ash or mahogany, and unless you express a preference, you get whatever you're given! This is capped, Les Paul style, with a figured maple top, either flamed or quilted, and flat other than a gentle arm chamfer. The rear has a Strat‑style tummy cutout on the top edge. All the analogue electronics are mounted from the rear and are found underneath a large plastic plate.

I wasn't initially sure whether I liked the neck or not, as it is based on a C‑section maple back with a fairly substantial, straight‑side ebony slab fingerboard, giving it something of a chunky boat shape. However, it is quite comfortable to play, so maybe it just takes time to get used to. The neck is kitted out with jumbo frets and there's just one abalone marker at the 12th fret, along with a full set of side dot markers in the fingerboard edge.

At the pointy end we see a straight string-pull over a low-friction nut, terminating in gold locking Sperzel tuners. The headstock is raked back at a sufficient angle to avoid the need for string trees, which is just as well, as this guitar has a Wilkinson fulcrum vibrato unit, again gold, which needs a friction‑free string path to achieve tuning stability. The fingerboard has a comfortable 12‑inch radius to facilitate choke‑free string bending, and the scale length is a Fender‑like 25.5 inches.

Almost all of the Moog Guitar's settings are made using these knobs and switches.Almost all of the Moog Guitar's settings are made using these knobs and switches.The saddles seem to be made from a synthetic material and are fitted with piezo pickups (their preamp is powered separately from an onboard, 9V battery) that can be blended with the output from the two magnetic pickups or output separately. The review model was finished in a rich brown transparent gloss, but numerous alternative finishes are available. As to the two pickups, these are both custom Moog items, as they hold the secret to the guitar's ability to extend or reduce the natural sustain of the plucked strings. They also produce the regular guitar sound which, to my ears, is rather lacking in top end, giving the pickups a somewhat dark humbucker sound rather than a single‑coil zing. Before going further, it is worth touching on the strings, as Moog have had these made specifically for them. They look conventional but they have a different magnetic makeup that works better with the special pickups, though you can use standard strings in an emergency. Sets are available in 9-46, 10-52 or 11-52 gauges.

The other part of the system is the included Moog Foot Pedal Controller, which also powers the guitar via the connected mains adaptor and the guitar's five‑pin XLR cable. A standard jack then takes the audio output from the pedal to the amplifier. This pedal can control the harmonic blend of the sustain effect when active, or the cutoff frequency of the Moog Filter, depending on the filter mode in use. There's also an input jack for analogue synth-style control voltages. or CVs (using the 0-5V standard), allowing external voltage sources to control the filter frequency. The guitar comes in a tweed case with a custom padded interior and a covered storage compartment for the foot controller.

Infinity & Beyond

So how do you make a guitar sustain indefinitely? A plucked string loses energy as it vibrates to create sound and eventually comes to rest, so to keep it vibrating you need to add energy in some way, to make up for the natural losses. Violin players do this using a bow. You can achieve an electronic bowing effect in an electric guitar by using a permanent magnet under the strings and then passing the amplified audio signal from a hex pickup along each guitar string to ground, as in the Roland GR500 guitar synth. Alternatively, you can amplify the output from the string via a pickup and then use that to drive what is essentially another electromagnetic pickup in reverse, to reintroduce energy into the string, as the E‑bow does. There's no detailed explanation of exactly how the Moog system works, but the designer confirms that it does feed energy back onto the strings magnetically with a separate pickup/transducer per string. I assume from this that each pickup cover hides a pair of hex pickups and hex exciters, almost like having six adjustable E‑bows per pickup.

A Full Sustain mode allows continuous sustain on every string, even open ones, while Controlled Sustain mode sustains only the notes you pick and damps all the others. A third mode brings in the active muting to shorten the natural sustain by draining additional energy from the strings. The sustain modes are selected using the gold‑tipped, three‑way lever switch at the bottom of the control panel, and. The black knurled knob closest to the neck adjusts the overall volume, while the gold knurled knob next door adjusts the strength of the sustaining or damping effect — something the manual calls 'Vo Power'! A further three‑way switch, this time a simple toggle, selects normal guitar tone or two Moog filter modes, Normal and Articulated. Articulated works a bit like an autowah, where the effect is triggered by picking a string and the filter frequency follows the string's volume envelope. In this mode, the pedal also controls the filter cutoff and so interacts with the picking envelope, and when the pedal is backed right off there's a hint of slow filter attack lending a synth‑like quality to the sound. In Normal mode, you control the filter directly from the pedal, like a regular wah. When the filter mode is set to normal guitar tone, the pedal controls the harmonic shift. The strings are treated separately where each has its own filter, so in Articulated mode each string controls its own filter envelope.

The gold knob nearest the bottom edge of the body controls the filter resonance when in filter mode but when normal guitar mode is selected it reverts to acting like a typical guitar tone control. The third gold knob, nearest the bridge, adjusts the harmonic balance of the feedback effect, essentially determining which overtones are added, in much the same way as moving an E‑bow along a guitar string changes the harmonic make-up of the sound. As far as I can make out, the harmonic balance shifts the string excitation point from pickup to pickup and the excitation works the same way regardless of which pickup — including the piezo — is selected.

A five‑way, Strat‑style pickup selector with a black cap offers choices of either or both magnetic pickups, in phase or out of phase, or just the piezo pickup on its own. When the magnetic pickups are selected, the black knob furthest from the neck blends the piezo sound with the existing pickup signal. Ergonomically, I found some of the controls to be a bit too closely packed for comfort and when adjusting the Tone/Filter knob I often found myself moving the Mode selector switch below it. Nevertheless, the control system is relatively simple when you appreciate how much control it gives you.

The Moog Guitar In Action

The Foot Pedal Controller. The five-pin XLR socket to connect it to the Moog Guitar can be seen at the top right corner.The Foot Pedal Controller. The five-pin XLR socket to connect it to the Moog Guitar can be seen at the top right corner.

If you're using the Moog as a straight electric guitar, you have to turn the Vo Power knob to minimum, otherwise the sustain effect is still as set by the mode selector. From a live performance perspective, it would have been useful to have an easily accessible Normal/Moog switch somewhere as during a performance you're likely to want to switch quickly from normal guitar to one of the sustain/filter effects — and as things stand you may need also to reset the tone/filter resonance knob at the same time. I have to say I wasn't very keen on the straight guitar sound from the pickups, as they sounded rather dull and lifeless to my Strat‑acclimatised ears, though the various tones on offer do work well with the filter and sustain effects, and those more used to humbuckers may well like them. Given the choice, I would have liked a filter envelope invert control, and some way of adding polyphonic distortion before the filters, to give them something more meaty to chew on!

The active damping effect is more endearing than I thought it would be, and is more reminiscent of a buzz‑less sitar than a banjo, which is what I'd half expected to hear. In Full sustain mode, the way open strings burst into life at higher Vo Power settings means you have to play very carefully in this mode to avoid chaos. Controlled Sustained mode is far more, well, controllable, as it still allows open strings to sustain but only if you pick them first, so it seems some form of picking threshold system is used to detect whether you intend a note to start sustaining or not. In most instances, full Vo Power is not necessary to create the desired effect, and using the pedal to vary the harmonic blend adds a nice sense of movement to the sound, though the generous application of delay and modulation effects does a lot to liven up the result too. What could work well, though it would add a bit of complexity to the controls and quite a bit to the circuitry, is to have the harmonic blend for each string driven from LFOs all running at slightly different frequencies.

I felt the filter was a bit limiting, not because it isn't a good Moog filter but because an undistorted guitar sound isn't really harmonically complex enough to give it a fair chance at being creative. The results I achieved were often thin and whiney or wah‑wah like, though they do help add interest and movement to what can otherwise become a rather samey sound. Tonally the sustain effect is quite E‑bow‑like, although, unlike the E‑bow, it is both polyphonic and can be modified by the vibrato bar without the need to grow a third hand. In some ways I find the E‑bow produces a more organic sound that can be controlled in a more interesting (if not always more predictable) way by the user, but then it takes a while to master the technique.

Verdict

Moog Guitar

The current incarnation of the Moog Guitar is capable of some unusual and creative effects that come directly from the player's fingers, making it very easy for a guitar player to get used to, but I think the unremarkable regular guitar sound counts against it and the controls could do with a rethink to allow for faster and more reliable changeover from Moog sustain guitar to conventional guitar. Having spent a lot of time playing on the instrument, I also found it a touch frustrating that none of the controls had markings, so it is impossible to pre-set a known good sound with any degree of accuracy or to know what sound to expect by just looking at the controls.

At this stage in its evolution, I think some of the better‑off professionals will buy one to use on recording sessions and perhaps for the odd live song but I can't see many players wanting to use this guitar as their main instrument, due to its over‑dark tonality. Having said that, the Moog Guitar enables players to create sounds that couldn't be achieved in any other way, such as sustaining a chord on some strings and then sliding a finger of the right hand on one of the other strings to pick out a violin‑like melody. It also lends itself to a semi‑tapping style of playing, where the tapped notes can be held as long as you like, and you can get some wonderful harmonic effects by tapping the strings with your finger to excite chords. A day noodling on this guitar and you have an instant New Age album!

I'm sure the Moog Guitar will inspire some of the more adventurous players to develop new techniques, and with the addition of some simple delay effects it can sound very surreal, but there were times when I felt more floor controls would make it more versatile — a way to adjust the Vo Power control via a pedal during performance, for example.

It might seem, from some of my comments, that I'm a bit down on the Moog Guitar but that wouldn't be true, as we need pioneering products like these to point the way to the future. I only tend to come out with a string of 'wouldn't it be great ifs' when I feel enthused by something, and though the Moog Guitar has the inevitable flaws and inflated price tag that comes with being the first of its kind, it's easy to see its potential. I thoroughly enjoyed playing it.

I've bought just about every guitar synth and sound‑mangling device out there, from the early ARP Avatar and Roland GR500 to the later Roland GR300 and current GR33, with several in between that I've completely forgotten! I also own and use a Roland VG99, a Line 6 Variax and several E‑bows, and can envisage elements from all these instruments and devices converging to give guitar players something truly wonderful. Moog's sustain system could be a major part of the picture. I don't think triggering samples is the right way to go for a guitar player, as it separates the sound from the player's fingers, but putting harmonic resynthesis, hex‑overdrive and octave shifting before the filters could vastly extend the capabilities of this type of instrument, as could putting Eventide‑quality pitch, modulation and delay effects after it. Some means of controlling the attack envelope, after the style of the old Roland GR300, would also add a lot of tonal flexibility, enabling the user to create synth brass and string‑like sounds without straying away from the guitar string as a sound source.

I really hope that Paul Vo stays with his concept and refines it further, because he's come up with an easy‑to‑use sustain concept that really works — and that's a big part of the puzzle, when it comes to creating something like a guitar‑meets‑synth that's more about the guitar and the playing experience than it is about purely emulative synthesis.  

Alternatives

There's really nothing quite like the Moog Guitar, though you could try your luck with six E-bows, five well‑coordinated friends and six Moog filters!

Published March 2009