Introduction

A suite of five self-contained keyboard programs for the enthusiast to experiment with. From chord organs to machine-code synthesisers, the programs can be fully listed, incorporated into your own programs or run independently. The following programs are included:

1. Simple 3-Voice Organ in Basic
2. Single Voice Machine-Code Organ with Pitch Bend
3. 3-Voice Machine-Code Organ with Envelope Generator
4. Chord Organ 1
5. Chord Organ 2

Running And Listing

Note that keys 2, 5, 9 and ^ are not black notes. This applies to all the programs. If you wish to use any portion of these programs on a commercial basis, you must first obtain written permission from Musicsoft.

Each program is called from the Menu. Press ESCAPE to go back to the Menu at any time. Press BREAK to see the listing of the program you have been using. Each listing gives the complete program for that particular organ and can be extracted for use elsewhere. There are some display procedures at the end of the complete program which you may need (lines 28000 onwards). Press ESCAPE then f0 to re-run the program after you have looked at the listing.

1. Simple 3-Voice Organ in Basic
   The complete program really consists of lines 1080, 1090 and 1100, which shows how easy it is to produce a simple organ. The sound is 'choppy' due to sounds jumping from channel to channel. It is possible to get rid of this effect, and this has been done in program 3 (3-Voice M/C Organ). Notice that the key pressed is found by INKEY and the data read each time by the FOR-NEXT loop. This program will work with 1, 2 or 3 voices.
2. Single Voice M/C Organ with Pitch Bend
   Key scanning is worked in machine code. The assembler listing has been kept simple so that it is easy to see what is happening. The other keyboards are extensions of this listing. Octave changing is by SHIFT keys. Note that use is made of the low octaves not mentioned in the User Guide. This involves using channel 1 and channel 0 together to produce one note. this part is in the Basic SOUND statement and can be clearly seen. An elementary pitch bend is incorporated, also in Basic. Because of the simple form of m/c, the notes do not revert to normal on release, creating an 'interesting' effect! This basic routine has been included here in a relatively uncluttered program for illustration.
3. 3-Voice M/C Organ with Envelope Definer
   The assembler code is far more complex in this organ because each key press has to be processed to find out the following: (a) Was the note pressed on the last pass? (b) Are there three more notes higher than this one? If so, ignore. (c) If the note is new, find a home for it. (d) Make certain that, until the key is released, or has three notes higher, it stays on the same channel. The function keys are programmed wth pre-set envelopes: f1 is the same as the original sound heard. There is an Envelope Definer for you to experiment with; this is explained fully in the program.
4. Chord Organ 1
   The keyboard is as before but each key gives a three-note chord. The type of chord is defined by the function keys 1-9. The chords may be made to sound open by using the Z and X keys (this takes the Third up an octave). The octaves may be changed with the SHIFT keys, but this facility should be used with discretion as the results at the extreme ends are unusual (and unmusical in sound). The chords available are limited to three notes by the machine hardware. The policy has been to provide Root, Third and Fifth where possible, but to miss out the Fifth when a four-note chord is played (i.e. Dominant Seventh, etc).
5. Chord Organ 2
   The keyboard here is limited to the top octave (letter O to Down Cursor). The chords all contain notes within one-and-a-half octaves, giving close position chords in various inversions. This is the way they are often played on the piano.

Loading

CHAIN"" (RETURN)