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Roland GK-1

Product Profile

New Roland Guitar Synth Gear

Warren Sirota

ROLAND HAS RELEASED A SPATE OF new products of interest to the guitar synthesist or would-be guitar synthesist, including a hex pickup adapter to turn any electric guitar into a synth controller, a sophisticated "brains box" to convert the output of the hex pickup into MIDI signals, and two rack-mountable synthesizer sound modules with MIDI implementations that are tailored to guitarists' needs.


The GK-1 ($250.00) combines a hexaphonic pickup with some extra controls for MIDI into a compact package aimed at turning any electric guitar into a guitar synth controller. The GM-70 pitch-to-MIDI converter takes the signals from the GK-1 and converts them into MIDI messages to control synthesizers.

A hexaphonic (or simply "hex") pickup produces a separate output signal for each string. Mixed signals from all the strings, as you'd get from a conventional pickup, are much harder to analyze and convert into MIDI messages. The GK-1's hex pickup is very thin (3/8") and mounts onto your guitar's body next to the bridge. For most solidbodies, installation of the pickup is simple: You strip off the protective backing from the adhesive, position the pickup, and press it into place. However, if your strings are more than 3/8" or so above the body at the bridge, you will have to drill two small holes into the body to install the pickup.

The hex pickup is permanently wired to a "unit holder," a piece of plastic that's also mounted on the body using the end pin and, in most cases, several more screws that must be inserted into the body. If your guitar has an unusual shape or a large tailpiece that won't allow normal installation, there are usually other places to mount the unit holder. A small plastic box with a connector cord to the GM-70 snaps into place on the unit holder, and the installation is complete.

When you use the GK-1, you don't sacrifice the original sound of your guitar. A short cord is provided to go from your guitar's output jack to the GK-1; the guitar's signal is then sent to the GM-70 along with the other signals. A balance control on the GK-1 allows you to mix your guitar's signal with the synthesized signal, and there's also an overall volume control. The GK-1 also provides two knobs that send out MIDI continuous controller messages. These can be employed as any MIDI controllers(modulation wheel or portamento time, for example).

All in all, this unit is easy to install and use on any Stratocaster or Les Paul shaped solid-body electric. If your guitar is different from these, if you have a large tailpiece, or if you have deep reservations about drilling holes into your guitar's body, then you should bring your guitar to your dealer's showroom and check out the installation before deciding on a purchase.


Roland GM-70

The GM-70 The GM-70 ($995.00) is the "brains box" of the Roland system, and it's responsible for converting the signals coming from the hex pickup into MIDI signals. In addition to the GK-1, the GM-70 can also work with other Roland G-series controllers (the G707, G-202, G- 303, G-505, and G-808), or guitars by other makers outfitted with these electronics.

The GM-70 handles the tricky pitch-to-MIDI conversion quite well. Its tracking is fast and consistent, although there is some time delay that's noticeable in many musical contexts. In order to cut out the delay completely, you'd have to use other technologies, such as wired frets, which are quite expensive and which may force you give up the sound of your natural guitar. The Roland system allows you to play your guitar as a guitar and as a synth controller, and it tracks as well as, or better than, any other pitch-to-MIDI system I've seen.

There's more to the GM-70 than speed, however. The software design of this box is excellent and especially well thought-out for stage applications. First, the GM-70 provides two separate modes of operation: poly mode and multiple mono mode. In poly mode, all of the MUM messages of all six strings are sent out on a single channel. This is the simplest mode to use, and it is usable with virtually all synthesizers. You just set the synthesizer to receive on the GM-70's MIDI channel, or you set the GM-70 to transmit on the synthesizer's channel.

In multiple mono mode, the GM-70 trans-mits each string's signal on a different MIDI channel. Therefore, notes you play on the first string would be sent out on channel 1, notes from the second string on channel 2, etc. There are two reasons that you might want to do this. If you have a multi-timbral synthesizer (one capable of playing several different sounds at once), then you can set each string to control a different sound. You might have the lowest two strings assigned to a bass-type sound, for instance, with the upper four strings set for harpsichord-style chording. The second reason that you might want to use multiple mono mode is to be able to use pitch bends effectively. Because of a quirk in the basic design of MIDI, the MIDI pitch bend message affects every note in a MIDI channel. In order to enable pitch-bending to work effectively in a guitar controller, it is necessary to give each string its own channel. Otherwise, bends on one string could cause notes being played on other strings to bend also, as if you were using a tremolo bar.

In allowing you to control one synth in poly mode at the same time as you control a different synth in mono, the GM-70 provides admirable flexibility. In fact, it lets you control up to four independent banks of synths simultaneously, with independent MIDI channels, modes, and transposition. Since you might have a different setup for each song, you can store your choices into presets and step through them in performance with an optional pedal called the FC-100 ($295.00) that plugs into the back of the GM-70. Not only that, but you can set up a preset to send out a different MIDI program change message for each channel when the preset is selected. This allows you to set up a song completely, including choices of presets on many differ-ent synthesizers, with one click of the foot-switch. A very nice implementation.

Additionally, the GM-70 provides back-panel connectors fora second footswitch and a footpedal. Either footswitch can be assigned as a switch-type MIDI controller, and the pedal (Roland recommends its own EV-5, $79.50) can be assigned to any MIDI continu-ous controller or other MIDI functions such as pitch-bend or aftertouch. The footswitches can be used for stepping through presets as described previously, and also for "hold," which functions like the sustain pedal on a piano. The MIDI pedal can be extremely useful in conjunction with a synthesizer or effects device that allows you to map MIDI continuous controllers to sound parameters (the Oberheim Xpander and Lexicon PCM-70 are prime examples of such devices). Roland is to be commended for including connec-tions for all of these devices on the GM-70.


Roland MKS-50

The MKS-50 is a 6-voice, velocity-sensitive, rack-mountable version of Roland's Alpha Juno-1 keyboard synthesizer with a fairly economical list price of $749.50. It's a solidly built unit with many useful features, including a MIDI implementation that is quite suitable for guitarists. Although its sound-creation facilities are not ground-breaking, they are relatively easy to under-stand and can produce a number of useful patches. Players desiring a basic workhorse unit capable of delivering many of the "standard" synthesizer sounds (such as Rhodes-like pianos, xylophones, string swells, and filter sweep-type special effects) will find this to be a useful instrument.

The MKS-50 features a multiple-mono mode that dovetails neatly with the multiple-mono mode on the GM-70 and some other guitar controllers. Although the unit is not multi-timbral (you can't get string swells and pianos out of it at the same time, for example), it can receive pitch-bend independently on six MIDI channels, allowing the guitar syn-thesist full freedom to bend any or all of the strings separately.

Sounds of the MKS-50 are produced, in the tradition of the Roland Juno keyboard series, by subtractive synthesis using a digitally controlled oscillator (DCO), a voltage-controlled filter (VCF), and a voltage controlled amplifier (VCA). Experienced synthesists will recognize this model. It's easy to use and understand, but with only one DCO per voice, and one envelope to apply to the DCO, VCF, and VCA, the possibilities for rich sonic design are somewhat limited. The rich internal Roland Chorus helps significantly to fatten-up the textures.

The factory presets contain a number of good tones in the "synth bass" category and quite a few different-sounding organs, as well as good flutes, a nice clarinet patch, pretty koto-ish sounds, and a number of long sweeps suitable for movie soundtracks. Many of the other instrument simulations, such as the brass and strings, don't come off very well. There are a lot of buzzy sounds in the the "synth lead" category that make a good complement to, or substitute for, a fuzzed guitar, but overuse makes them wear quickly for me.

The MKS-50 has two additional features that add greatly to its utility. First of all, it is velocity-sensitive, which is pretty much a requirement for any sound module for guitar synthesis. The velocity can govern the extent to which the envelope affects the pitch, filter frequency, and VCA. Also, for soloing Roland has a feature called "chord memory." If chord memory is turned on in the patch you're playing (you have to experiment with this yourself—none of the factory presets use it), then every time you play a note, a chord will sound, and as you play different notes, the chord will be transposed. Sixteen chords at once can be in the MKS-50's memory, and you can either use the ones that Roland has preprogrammed or enter your own. This fea-ture is definitely a lot of fun.


Roland MKS-70

Now we come to the MKS-50's big brother, the MKS-70 ($2,295.00). Twice as large and more than twice as meaty, the MKS-70 adds extra features along with extra voices. It is fundamentally bi-timbral; that is, with a sequencer or with your guitar controller, you can play two entirely distinct sounds at once (each available independently at the back panel in stereo and mono outputs, which can be very handy for multi-track recording). Roland calls these the "A" and "B" tones. A patch can be set up so that both tones sound together, so that low notes sound one tone and high notes sound the other, or even so that the tones mix together in different degrees depending upon velocity (play it loud and hear trumpets braying; play it soft, and it's almost like praying - apologies to Stephen Sondheim).

Not only do you have twice as many timbres per note as with the MKS-50, but each tone is also richer. The tones are composed of two (rather than one) oscillators apiece, assisted by two envelope generators. With four envelopes per note to play around with (two per tone, two tones per patch), you have a good deal of latitude to be creative.

The only MKS-50 feature missing in the MKS-70 is the chord memory function. This is more than compensated for, however, by the much richer sounds (which you could program to sound a four-voice chord for every note anyway). Also, the MKS-70 has a car-tridge slot, which is very handy for voice storage. Each cartridge ($89.95) can hold 64 patches.

A tasty option for the MKS-70 is the PG-800 programmer ($350.00). This little gizmo plugs into the front of the MKS-70 and pro-vides you with knobs and sliders to make tone editing considerably easier than via the industry standard method of a small LCD screen and parameter buttons.

There is more icing on the cake. The MKS-70 has a function called "Chase," which can be added to any voice. This basically gives you a scaled-down delay unit built right into the synthesizer box. A nice touch.

What don't I like about the MKS-70? My biggest problem is the documentation. This is a fairly complex instrument, but there is no block diagram showing all the tone parame-ters and their interactions. MIDI control of the tone banks, although given several pages of treatment, is still unclear. Also, the "DCO XMOD" function, a potentially important feature (which might, as far as I can tell, give you FM-like capabilities) is barely explained at all. My only other qualm about the MKS-70 is its two-timbre-at-a-time limitation. I have played in situations, albeit rarely, where I wanted to get a different synthesizer sound from each guitar string. This isn't possible with this unit.

However, aside from that, this is a unit that makes a lot of pleasant sounds, and could be the foundation for a lot of good music.

Manufacturer's Response

Roland Product Specialist Paul Young-blood replies, "We have already seen the GM-70 gain widespread acceptance and popularity because of its extensive MIDI implementation and ability to track any playing style. Although the GM-70 review was very thorough, I would like to add a few features not mentioned. The external control pedals and footswitches can also be assigned to MIDI functions other than continuous controllers. For example, an EV-5 pedal can be assigned to control aftertouch for functions such as opening up the filter, or adding modulation or volume. Bend up/down can also be assigned for whammy-bar effects.

It's also important to note that with a MIDI sequencer, such as the Roland MC-500, all the functions and performance parameters of the GM-70 can be recorded and extensively edited. This allows guitarists to use MIDI and the GM-70 as a complete production system. Regarding the MKS-70 documentation: Like other manufacturers, Roland's manuals are used primarily to explain operational procedures, rather than creative aspects such as synthesizer programming. However, these types of subjects (and new patch parameters) will be covered extensively in future editions of Roland's free publication, Roland Users Group."

Copyright August 1987 Guitar Player Magazine