Guitar Synthesizers and the Use of Hex Pickups

Mention the idea of ‘midi guitar’ to most guitarists and the image that springs to mind is most likely an ’80s cover band with skinny ties where the guitarist has to cover the keyboard parts to ‘Jump’ and ‘Safety Dance.’ That is, if you don’t get the outright dismissal of the use of guitar synth in music making. I was there too. The last thing I want to sound like is a terrible keyboard player. I don’t want to carry an instrument that looks like a keytar. In this article I want to present an overview of what we call ‘guitar synthesizer’ and describe how I use it in my own compositions.

First, a little history lesson. Guitar synthesizers were conceived at the dawn of the 70s, but most manufacturers didn’t get working models out to a mass amount of musicians until about 1976. During that time, Roland came out with their GR500 system, and ARP came out with their Avatar, famously used by Pete Townshend.

In the late 70s, Electro-Harmonix came out with their ‘Guitar Synthesizer’, a rack-mount monophonic synth with three oscillators. I actually owned one of these beasts, and apparently Steve Howe used one on Drama from Yes.

Yes, I had one, and no, it didn’t sound good.

All of these synths had one thing in common – they sounded like a bad Atari gaming system thrown down a flight of stairs. The bleeps and drones had more in common with Pong than any known instruments, and with this, guitarists developed a well-deserved bias against guitar synthesis.

This is how you’d connect 2 synthesizers together.

Enter 1983, when MIDI was developed. It was a language of standards (unheard of in the musical instrument industry) that allowed synths to talk to each other. In other words, you could play the keyboard on one synthesizer, and hear the sound that was stored in another. This had a huge impact on guitarists.
If guitarists could translate a string sound into MIDI, you could send a midi signal to the instrument of your choice. With the advent of stored samples, you could actually sound like a piano, Hammond B3 or bassoon.
The problem is that in order to do that, you needed a special pickup on your guitar. It is called a hexaphonic pickup, and think of it as a tiny pickup that allows you to send each string to its own sound. You can process each string separately, and send each string to its own sound. Imagine sending each string to its own pedalboard and amp. Yeah, you could do that.
Hex pickups developed by Roland eventually settled on one shape. The current model, the GK-3, mounts on your guitar between the bridge pickup and the bridge. The signal goes to a control box, mounted externally to the guitar, and sends an analog signal for all 6 strings to the next device in line.

The Roland GK3, on an LP. Seeing this, the guitarist in me dies a little.

The next device can be a guitar synthesizer itself, which will sense what pitch is played on each string, and triggers a sample of that sound. Foot pedals like volume and hold are common devices for guitar synthesists just as they are for keyboardists.
Another option is a midi interface, which translates the information from each string into a MIDI note number, as well as a velocity – it senses how hard you played the string. The signal is then sent to another device to trigger the sound.
The problem with all of this is what we call latency. Latency is how long it takes from the time you play until you hear the sound out of the speakers. With older units, the high latency contributed to the bad rap guitar synths got. Every guitar synth suffers from latency, although current systems are so fast, you generally don’t hear it, but you may feel that the notes don’t sound as immediately as magnetic pickups. Your technique should be great, and remember to not rely on so many guitar-isms, like hammer-ons, slides, strummed chords and bends in predictable places, or else you sound like a bad keyboardist.
Hex pickups aren’t relegated to a Borg-like box on your guitar, either. Many guitar makers, like Godin, Carvin, and Gibson have guitars with built-in hex pickups. Usually, these are in the form of piezos, a special pickup built into the bridge saddles of the guitar. Usually used to get a faux-acoustic sound from an electric guitar, they have a very clean look, and the only thing you see on the guitar is a special 13-pin jack that can plug into a synth.
Newer systems promise wireless MIDI signal to VST synths on your computer with less than 15ms latency. And I have even heard of USB-equipped guitars in the works promising magnetic, hex, and acoustic sounds going to a computer over a single USB cable.
And with everything getting smaller, you knew it had to happen: Rick Hanes Guitars built a travel guitar with not only a hex pickup, but with an iPhone dock built into the guitar itself. Even cooler, it features a Seymour Duncan Invader set.

My Line6 Variax Acoustic uses a hex pickup for altered tunings, 12 strings and sitar sounds, among others.

Hex pickups, don’t always have to be for guitar synth. Getting a separate signal for each string allows for the tuning and guitar modeling in the Line6 Variax guitars. Imagine processing and pitch transposing each string separately, and panning the results across the stereo spectrum. As digital modeling becomes more and more a part of the modern guitarist’s world, the secret will be in getting those 6 signals out of the guitar. Instrument modeling? Already here. Unlimited tunings? Yeah, we have had that for years. Pickup modeling? I don’t know, but it would certainly be cool. Imagine a pickup switch not only switching between different magnetic pickups, but one switching between modeled pickups, in any tuning you want. The technology is there right now to do it- and it most likely would involve the use of some sort of hexaphonic pickup.
As a modern guitarist into technology, I am excited about whatever the future brings just as much as I love classic guitar sounds that made me want to pick up the guitar in the first place. With the recent advances in polyphonic pitch detection from a mono source (the Hardwire Polyphonic tuner comes to mind), we may not need hex pickups at all. But for now, it allows one guitarist to expand their palette in their home studios without relying on a skinny-tied keyboard player.
Here is a quick ringtone I recorded. Keys, horns and bass are guitar synth.

Ever use a guitar synth? How about a guitar with piezo pickups? How would you process each string separately to get sounds the world has never heard?

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19 Comments

    1. Thanks! The past and the future are both important, but I am always looking for new ways to get the sounds out of my heard. I usually won’t settle for something ‘because it has always been done that way’.

  1. Well, what I’m doing to bypass this latency issue is, 1. I bought a minimoog voyager synth recently and today I’m picking up my Sonuus GM2 midi pitch to voltage converter. You can plug the guitar into a standard 1/4″ jack on the Sonuus and the synth into a midi plug on the Sonuus. The only drawback is that the guitar can’t play chords like a Roland GR-55. But,if I need chords I can always bypass the synth. Having said that about not being able to play chords,with the voyager’s 3 oscillators, I should be able to play up to a 3 note chord using one string and I’m excited to do that when it arrives today. This thing was only $99 at Sweetwater Music.

    1. I have never tried the Sonuus, but technology is getting pretty close to being able to play chords without using midi. Perhaps in a few years polyphonic pitch detection will be all over the place.

  2. To add a little context to players who aren’t used to the idea of dealing with latency and what such delays feel like to your playing, a few milliseconds is the equivalent of standing a foot closer or further away from your amp. Given how far a guitarist might roam on a large stage, these sort of delays are generally imperceptable.

  3. An interesting overview and one that hopefully goes some way to shedding some light on what is often dismissed as a gimic.
    I have been using guitar synths for many years now and I can honestly say that the GK3 when correctly installed can give near-perfect tracking and the latency is so slight that its really not an issue. As mentioned above as long as you keep in mind that you cannot get away with the usual playing techniques then you are fine. I use mine in live situations, from doubling my guitar lines with flithy syth basses or pad swells etc etc the possibities are endless……..
    If you record at home then I would say a guitar synth is an essential part of your set up as it will allow you to control those pesky VST instruments without having to play the keyboard !

  4. the Roland unit is advertised as having 6 mini-humbuckers, and the Godin and others say their pickups are piezo based. Which tracks better with fewer anomalies? Also which tracks better – hex pickups on solid body or on hollow body guitars; and finally do ebony fingerboards really track better than say maple fingerboards? What then is the best combination?
    Thanks much!

  5. Some of the old synths sounded like smack, but the GR-300 in Pat Metheny’s hands has always been a super-low-latency, very expressive analog piece of goodness (because it never does true digital/MIDI conversion). The guy still uses it to this day. It does use a hex pickup guitar controller.

  6. I’ve just picked up a Shadow GTM6 and am looking for compatable hex pickup systems, it seems like the cable input is a standard 1/4 jack. Any ideas where to start? Would the gk3 work?

    1. Apparently, the Shadow GTM6 uses a proprietary system decoding the hex sounds. It uses a TRS cable in its own format. So, the GK3 would not work at all. I found this statement: “The Shadow GTM6 system employed an onboard analog Multiplexer, to send all 6 string signals over one TRS 1/4” phone plug connection. It was a proprietary system that relied on the Rack Mount Shadow/Ovation/Takamine /Charvel GT6M unit to decode these multiplexed signals. Sad to say it does not “play well” interfacing with other Guitar Synth systems.”

      1. Cheers, I found that much after posting here. I’ve emailed Shadow to see if they do anything, looks to be a tricky on for replacements. I saw someone suggest the SH-1500 MU, but no sign if it worked or not

          1. Ive had a reply from on part of Shadow who have suggested the externally mounted SH 1550 MU, am just waiting on a price. Will keep you informed

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