Monday, April 27, 2009

Roland GR Systems: Some Questions and Answers - part 01 - 1984


ROLAND SERVICE
Roland GR Systems: Some Questions and Answers (part 01)

by Mark Altekruse

Roland has been making guitar synthesizers since 1977.

The GR-500 was the first in a line that has also included the GR-100 and GR-300.

The GR-700 was introduced to the public in January of 1984.

As the first programmable polyphonic synthesizer for guitar, the GR-700 has features beyond those of many sophisticated keyboard synthesizers.

Keyboardists have had the opportunity to assimilate the technology of the synthesizer over the last two decades.

Guitarists, for the most part, haven't had that opportunity.

The GR-700 is getting into the hands of more and more people everyday.

These people, unfamiliar with synthesizers, are calling Roland's Service and Product Support departments with a lot of questions.

We've decided to answer, in print, the most often asked questions.


I've tried out the GR-700 and found that it doesn't respond fast enough to my playing. Is there a tracking problem ?

The correct term, in this case, is lag time.

When a string is played on a guitar controller, it vibrates at a certain rate.

A device that counts the vibrations of the string is used to send this information (pitch, on/off, etc.) to the GR-700's oscillators.

The counter is very fast, accomplishing its job within two cycles of the strings vibration.

This complex processing system, when used with certain "patches" on the GR-700, can produce a short lag time.

The lag time can be corrected/ adjusted in two ways.

First, the envelope of the patch and the sensitivity of the guitar controller can be adjusted.

Second, the frets of the guitar could be wired to transmit pitch instantly just like the on/off switching of the keyboard synthesizer.

The first solution is acceptable, but might not totally solve the lag time problem.

The second solution solves the problem, but the guitarist must give up all of the techniques that make his instrument unique; i.e. string bends, hammerons, and harmonics.

After trying the first solution and avoiding the second, what else can be done ?

We've found that if a guitar controller is properly set-up (intonated etc.) and patches and sensitivity are adjusted to compensate for an individual's playing style, 99% of the problems are solved.

What about the 1%? You may have to learn to live with a little lag time.

You may have to learn to "play on top of the beat" like instrumentalists in the back rows of an orchestra must, so that their sound will hit the front row at the same time as the instruments being played from those front rows.

Sometimes while I'm playing I will find that one or two notes that I am sustaining will "jump" octaves by themselves. Is there something wrong with my guitar controller or my synth? If not, what can I do to keep this from happening ?

The octave jumping that you are referring to is called "glitching."

A glitch occurs when the synthesizer module misinterprets the note you are playing or misreads the strings vibration.

The resultant sound is often less than satisfactory, but there is a way to prevent the problem. Since the module is solely dependent on a good, solid string vibration in order to accurately reproduce the note or chord you are playing, it is essential the guitar be in tune with itself !

A guitar controller, or any guitar for that matter, can only be in tune with itself if it has undergone a process known as intonation.

Learning how to intonate a guitar is not difficult. If you are not familiar with the process, we recommend that you see a qualified guitar technician in your area. This service should be performed on a regular basis.

When I try to tune my GR-707 synthesizer to a tuner, I can 't get it to a center of A = 440 Hz. It usually is 10 to 15 cents flat or sharp. Is there something wrong with my module ?

The GR-700 has a P-ROM which allows it to have multiple tuning centers.

This is done because other countries do not use A =440 Hz as their standard. Just like they don't use inches, they use centimeters etc.

The GR-700 is set at the factory for a tuning of A = 442 Hz. It is a very simple process to readjust the module's tuning center.

First, Turn on the GR-700 and wait until the display shows its default Bank and Patch numbers (1/1).

Second, Press the Edit footswitch. The display will read CF on the left side and a percentage number on the right.

Third, Press Edit numbers 4 and 8. This is the tune function of the GR-700.

The display will read 48 in the left and a single number on the right.

Fourth, plug a tuner (BOSS TU-12) in at the MONO Output of the GR-700.

Fifth, Play the first string while depressing the Hold foot-switch. A constant tone will sound.

Sixth, make sure that only the synth sound is audible. Use your Balance control on the controller.

Seventh, Turn the Edit/Resonance control until the meter on your tuner reads exactly A = 440 Hz.

Eighth, Release the Hold and tune the guitar (change your Balance control so you hear the guitar) to the synth module. That's right, the guitar gets tuned to the module.

Ninth, hit the Edit switch again, turn the Memory Protect switch off, hit the Write switch, hit a numbered footswitch and the new tuning center will be stored in memory.

From Roland USERS GROUP magazine 1984

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