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Atari Music Composer Cartridge



The Atari Music Composer is a plug-in ROM for use with Atari computer systems. The cartridge can be used with either the 400 or the 800 personal computer, and in both cases it replaces the BASIC cartridge. Facilities for saving your compositions enable both disk-based and cassette-based systems to be used, and obviously the amount of memory the system has governs the length of your composition.

Our cartridge was tested on the Atari 800 with 48K of memory, providing the facility to store up to 13,880 notes. The number of notes available for composing, with a given memory capacity, is as follows:
48K:13,880
32K: 9,784
16K: 1,592
These figures were obtained after the disk operating system had been loaded

The 21-page manual provided is in four parts: a general description, a sample session, a description of the music file structure and a quick reference guide. The manual assumes you have some musical knowledge, but not that you are used to using a keyboard. Each keyboard entry is explained step by step. This, combined with printed examples of computer responses and screen displays, means that anyone unfamiliar with keyboards should have very little problem. Although a difficult item to write a manual for, we felt that the description of the various functions and commands left much to be desired.

Figure 1. Main MENU.


Figure 2. EDIT MUSIC.


Bass Clef music.


Choosing the Menu



The programs contained in the ROM are menu driven. In other words, you are given a list of options to choose from. This, in most cases, leads to a further sub-menu, from which parameters can be set. When the cartridge is inserted into the machine you immediately enter the main menu. This lists the sub-menus (Figure 1). The options available are outlined below:

EDIT MUSIC. This leads to a submenu (Figure 2), the first item of which is PHRASE. This resembles a phrase in music, in that it groups notes into sections. However, unlike a musical phrase, it does not denote accents or context, but rather enables you to move sections of music around in your arrangement. There are 9 different phrases available.

METER. This sets the time signature, which defaults to 4/4 unless told otherwise. Since there are no accents available this is of limited use, but combined with another function, CHECK MEASURES, it becomes impossible to exit from a bar that does not contain the correct number of notes.

KEY SIG. You can write in any key by simply typing the number of #'s or b's needed. Accidentals may also be written in as they occur.

TEMPO. This is programmable between 1 and 9, 1 being the fastest.

Having set these parameters it is now possible to proceed and write the first phrase. Two musical staves are displayed on the screen - the treble and bass clefs. This is because there is a choice of pitch which ranges over 3 octaves.

For the purposes of writing you are provided with a cursor, which may be moved horizontally back and forth. Thus enabling you to delete or insert notes in the required position. Also displayed are: an indication of the phrase you are in, the bar number, the number of notes free, and an entry prompt. An example of how easy it is to enter notes is given in Figure 3.

After setting the measure of bar number, the notes are entered as follows: the first letter is the note required, N, F or S will denote natural flat or sharp respectively. Then you need the octave numbers. 3 to 6 are valid, and after one note has been entered you stay in that octave unless you specify otherwise. Next is the length of note required, which ranges from W for a 'whole' note or breve, down to T for a 32nd note or demi-semi quaver. Lastly, if the note is tied or dotted you must type in T or respectively. Rests are entered as R, plus desired length.

As each note is entered the notes of that measure are played, which is a help if you are composing, but can be a hindrance if you are simply entering notes from sheet music. Once composition of the phrases is complete, you can proceed to the ARRANGE MENU.

ARRANGE MENU. The first thing asked for is which of the 4 voices you wish to arrange. After entering the relevant number you are presented with the heading ARRANGE VOICE (plus the number you entered) and a list of line numbers from 1 to 20 on the left hand side of the screen (Figure 4). One of these numbers is a different colour from the rest. This represents the cursor and can be moved vertically using normal cursor controls, thus allowing deletion or insertion of lines. At the bottom of the screen you are presented with a row of 8 letters: C,D,G,M,P,S,T,V. If M is selected the full ARRANGE MENU is displayed (Figure 5). The functions provided are: COUNT. This enables you to set up a loop and is used in conjunction with GOTO; DISPLAY can be used to show the notes on the screen as they are played; GOTO enables you to jump back and forth in your arrangement and can be used with COUNT for repeating passages a specified number of times; PLAY PHRASE is self explanatory, and is accompanied by a number from 1 to 9 denoting the phrase you wish to be played; STOP, as in all other menus, exits to the next menu; TRANSPOSE allows you to transpose a phrase up or down, in semitone steps. Numbers from -36 to +36 are valid, but have to be used with some caution, as it is possible to transpose music out of the 3 octave range. If this happens the machine will do the best it can; VOLUME. This is adjustable between PP and FF.

This set of instructions provides a very powerful, high level music programming language. A sample arrangement for one voice is shown below.

1 DISPLAY
2 VOLUME MF
3 COUNT 3
4 PLAY PHRASE 1
5 GOTO 4
6 TRANSPOSE 12
7 COUNT 12
8 PLAY PHRASE 2
9 GOTO 8

The next items on the main menu are SAVE and RETRIEVE. Upon entering the SAVE menu (Figure 6), the first thing to do is enter a file name. Having done this you will be asked WHICH? At this point the following options are open to you: save EVERYTHING, ALL PHRASES, ALL VOICES, PHRASE X (a particular phrase), VX (a particular voice). RETRIEVE offers you the same facilities.

Files saved using the Music Composer can be used from BASIC and a comprehensive breakdown of the file structure is given in the manual provided. The details are too complex to describe in a review, but basically each file is made up of four sections. Each record starts with a header byte enabling you to locate the starting point. A phrase record contains pitch and duration values for a given phrase. The voice record is the actual program for playing one of the four voices. There is also a miscellaneous information record in which the time signature, tempo and key signature are stored.

The DOS instruction in the main menu is for use with disk-based systems and when selected, returns control of the machine to the disk operating system, thus enabling use of all usual DOS commands. This command is non-destructive and on exiting the disk operating system, using option B which is RUN CARTRIDGE, you will find your composition intact.

LISTEN enables you to hear everything from the arranged programs.

Figure 3. Entering Music.


Making Music



Having explained the functions provided we shall now relate our experiences of using the cartridge. We decided to approach this review in two ways. From the point of view of users with little or no musical knowledge we thought a good test would be to enter sheet music and for those of you who are musically adept or more adventurous, we composed a 24-bar piece of original work.

In order to enter sheet music it is obviously necessary to identify the notes their duration, and symbols such as rests and sharps, flats, etc. With a little patience and a prompt table, those with no musical knowledge should be able to master this in a short period of time. The manual is also very useful here as it lists note durations, octave spacings and symbols.

After a quick trip to a local music shop we had our eager hands on some popular music for piano. We found the best approach was to initially number the bars and then write the code for each note immediately beneath it. At this point we assigned each of the four voices in the music to a phrase. We then typed each phrase in turn, only to realise that many sections of each phrase (the verses and choruses) were repeated and we should have split the phrases up further and then used the ARRANGE facility to play them in the correct order. This entails more time spent on planning, but much time is saved at the keyboard and the possibility of typing errors is reduced.


Upon listening to the result it was obvious that we had made a number of errors. Some of these, such as a note in the wrong octave, were quickly located and we found the cursor controls very effective for correcting these errors. Other errors were harder to find. The answer is to take your time and get it right in the first place. Although most sheet music can be entered, the machine has difficulty in coping with some aspects, not least of which is the lack of emphasis on individual notes. This can make some music sound noticeably different. Triplets, some turns and some trills are not possible and obviously rallentando, crescendo, diminuendo and glides etc. are out.

For our second test we entered a four-part composition having phrase one as the melody line, phrase two as the first harmony, phrase three as an arpeggio rhythm and phrase four as bass. We changed things as we went along, replacing a triplet with a single note, for example, and altering notes which though musically correct, sounded slightly wrong on the computer when the four phrases were played together. This, we suspect, is because all the voices have the same timbre. CHECK MEASURES proved to be invaluable as it is easy to forget the step to the next bar when concentrating on writing the notes, and when you try to exit the error message MEASURE TOO LONG is displayed so the error may be corrected almost as soon as it is made.

Figure 4. ARRANGE VOICE.


Figure 5. ARRANGE MENU.


Figure 6. SAVE MUSIC.


Conclusions



Considering that this is the cheapest way of generating computer music, we feel the 'Music Composer' represents outstanding value for money. The emphasis is more on fun than on serious music making though for anyone who has always wished to know something about music, but has been put off by text books and terminology, this could be a fun way to learn. As a classroom teaching aid it would definitely hold a student's attention, without too much teacher involvement. For the professional musician it promises much, but you may soon find yourself restricted by this particular composer's limitations. However it is, after all, written for a home computer system. And no doubt more sophisticated programs and peripherals will become available in due course.

We wish to thank Ingersoll Ltd. for the loan of a cartridge, and a pre-production Atari 800.



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Micromusic: Notate your Nascom

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Basically Basic


Electronics & Music Maker - Copyright: Music Maker Publications (UK), Future Publishing.

 

Electronics & Music Maker - Jul 1981

Previous article in this issue:

> Micromusic: Notate your Nasc...

Next article in this issue:

> Basically Basic


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