AOH :: SIDNEWS3.TXT|
SIDPLAYER NEWS #3 March 1986
Welcome to the third news file for Sidplayer. This document describes how to
use POLYCON, the polyphony conversion utility.
The polyphony effect occurs when one sequence of notes is played alternately
on two voices. For example, voice one plays the first note, voice two plays
the second note, voice one plays the third note, and so on. This allows each
new note to start playing while the previous note is still fading away, for a
pleasant, continuous sound. The effect is heard at a few places in the song
HOMECOMING and in most of the song FUER.
The POLYCON utility converts a song so that the notes in one voice are played
with the polyphony effect. To do this, it copies the notes in the one voice
to a second voice that is not being used, and then changes every other note to
a rest. The first, third, fifth, etc. notes on the one voice will be changed
to rests, and the second, fourth, sixth, etc. notes on the other voice will be
changed to rests.
To convert a song, load and run the POLYCON utility. Enter the name of the
song to be converted, and wait for the song to load.
The source voice is the voice which contains the notes that are to be played
with the polyphony effect. When prompted for the source voice, enter the
number of the voice which has these notes.
The entire voice may be converted, or only the notes in a specified range of
measures. Enter the number of the measure where the conversion should start,
or just press the Return key if you want the conversion to start at the
beginning of the voice.
Next enter the number of the measure where the conversion should end. The
conversion will stop at the beginning of this measure. For example, if you
specify that the conversion should stop at measure 50, the notes up to measure
50 will be converted, but those in measure 50 will not be converted. Press
only the Return key if you want the conversion to continue to the end of the
If you do not convert the whole voice, and enter a number for the beginning or
ending measure, or both, the voice must contain corresponding measure markers
with the same numbers. The POLYCON utility searches the voice for these
measure markers to find where to start and stop the conversion. If the
measure markers are missing, the program will report an error.
The program next asks you to specify which voices are to be used to produce
the polyphony effect. Press the Y or N key to specify yes or no on each voice.
The polyphony effect requires that two voices be used. The source voice can
be one of these, so be sure to type Y for the source voice.
The second voice should be one that is not in use - not playing any notes -
while the polyphony notes are being played. If you are converting an entire
voice, this second voice must be empty. If you are converting only a range of
measures, the second voice should be playing only rests during those measures.
Decide which voice will be the second voice, and type Y for that voice number.
Type N for the remaining voice.
If the conversion is being done on a range of measures, there must be
corresponding measure markers in the second voice as well as in the source
voice. The utility will report an error if it cannot find the starting and
ending measure markers in the second voice.
Any notes, rests, or commands between the measure markers in the second voice
will be deleted and replaced with the polyphony notes.
After you have responded with Y or N for each voice, the utility will perform
the conversion and ask you if you want to convert another part. Type Y to
repeat the above procedure, possibly using a different source voice.
When you are done and do not want to convert any more notes, just type N at
the prompt asking if you want to convert another part. Then enter a filename
and wait for the program to save the converted song.
You may need to go back to the Sidplayer Editor and add slower release rates
to the polyphony voices to make the polyphony effect more noticeable.
Also remember that you can always use the Editor to examine someone else's
song to see how some of these advanced techniques are used. For example, you
may want to look at how polyphony was used with detuning for an interesting
effect at the beginning of the song ISLAND. Polyphony also creates a nice
effect on fast arpeggios; it does not have to be used just with slow notes.
The polyphony effect can also be done using three voices. Just type Y for
each voice when prompted. Be sure that the two voices other than the source
voice are not playing any notes during those measures when the polyphony
effect is desired, as those notes will be deleted by the utility and replaced
with the polyphony notes.
The POLYCON utility has one other use besides converting a song for the
polyphony effect. If you specify that you want polyphony on only one voice,
and that voice is the source voice, the program will print an error message,
because polyphony can not be done with only one voice.
If the polyphony voice is different from the source voice, however, the
program will only print a warning message that a non-polyphonic arrangement
has been selected, and will then duplicate the specified range of measures
from the source voice to the polyphony voice without changing any notes to
This can be useful occasionally when you want to have the exact same sequence
of notes on two voices. One application is when you want to use the advanced
technique of having two voices synced together with the TPS value changing
every few notes. It is a lot easier to just duplicate the notes than to
define and call several phrases, each phrase being only one or two notes long.
As a final comment, remember that once a part of a song has been converted,
there is no easy way to undo the conversion. It may be a good idea to keep a
copy of the song without the polyphony effect.
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