TRANSCRIPT SID CLASS 11-15-87: Remember last week we talked about how envelope voice settings should fit the song and reflect the mood of the music. If you can catch onto this trick, then that's half the battle. A trick to pass on is putting a rest on each voice right before measure marker #1, before any music is played. I usually use a half note rest for this, but it depends on the tempo. Use a shorter rest if you're tempo is slow. It gives a short pause before the music begins. This helps the player programs "catch up", instead of jumping from loading to instant play. Be sure to put the same rest on EACH voice, however; if not, you're voices will be out of sync. Likewise, place a rest at the very end of the sid, too. This allows the last note to fade naturally, instead of being abruptly clipped off. The rest duration here depends on the tempo and the release setting; if you hear that the final note is still being clipped, increase the rest duration at the end of the sid. Vibrato can be very important to your envelope settings. It can make the sound more alive and natural. But if you use it, be sure to use it correctly and make it FIT the envelope you've chosen. Vibrato can be set separately on each voice, and it requires two separate commands. The first, VDP, sets the vibrato depth. The second, VRT, specifies the vibrato rate. There are no default vibrato settings, so the first time you turn it on you should use both of the above commands. To turn vibrato off, use VDP 0. These two commands require some time experimenting to get the affect you want. An easy way to begin is: VDP 8 VRT 2 Notice how this sounds, and increase or decrease the settings to achieve what you want. A trick used by many Sid Artists is to increase the vibrato as a note is sustained. For instance, if you have a sustained whole note, turn off the vibrato at the beginning of the note, then split the whole note into four tied quarter notes . Turn the vibrato on right before the second quarter note is sounded , and increase the vibrato before each successive note. This trick requires some time, but the effect can be dramatic. An example of a sid using this effect is: cry/river.mus. Load the .mus file into the Editor and see how this sid was set. The pulse width command should be used with the pulse

waveform. It has no affect on sawtooth, triangle or noise waveforms. The default P-W setting is 2048 . Try using different P-W settings to hear the different values they produce. Values smaller or larger than 2048 produce rectangle waves. The farther away the value is from 2048, the waves become narrower and the volume begins to decrease. The pulse wave is inaudible when the P-W is set at either 0 or 4095 . Remember, each voice can be set separately with its own envelope. For instance, if you use a P-W value of 500 on your lead voice, and a P-W value of 2048 on your bass voice then the bass will overpower the lead voice. The total sound shouldn't be flat, but with depth. The lead voice should be in the foreground, easily noticeable. The ryhthm or accompaniment should be in the middle ground -- it's there for a reason, but it shouldn't compete with the lead. Bass is in the background. P-W settings can help you achieve this. Volume cannot be set separately on each voice. It is set on one voice only. The default volume setting is 8. Try not to use VOL settings above 12, even though the master volume can go to 15. A setting of 15 can distort the sound on some speakers. It doesn't matter on which voice you set the volume, but set it on one voice only. Last week we began discussing repeats used in music. The HED/TAL command is used for a simple repeat. However, often you'll find the repeat has a first and a second ending. This means that one set of notes should be played at the end of the sequence the first time through and the second set of notes should be used as the endind the next time through. The HED/TAL cannot handle this kind of repeat. For this, we need to DEFINE A PHRASE. If a simple repeat is like a loop, then a defined phrase is like a subroutine. It is defined, and called when needed. DEF/END/CAL are the commands. To define a phrase, enter the DEF command. This command needs a number . Caution: each voice must have it's own DEF number value. Do not use DEF 2, for instance, on all three voices because when DEF 2 is called all three voices will call that same phrase. DEF is placed at the beginning where beginning repeat symbol is found. This marks the place where the music will jump back to in the repeat. After the last note of the phrase and before the first ending of the repeat, place the END command. It has no data value, so enter it by typing any number. This marks end of the definition and the notes are ready for calling. To call the phrase, enter the CAL command. The CAL is placed immediately ::before:: the second ending notes. It calls the phrase that you defined with the DEF command and uses the same data value you used for the DEF value. Example: DEF 0 is entered at the beginning of the repeat. Playing continues, encounters the END command. This has no affect until the phrase is called, so playing continues on into the first ending of the repeat. The command CAL 0 sends the playing back to the beginning of the repeat, where DEF 0 is marked. Playing continues the second time until it reaches the END command and jumps to where the CAL 0 was entered and plays the notes following CAL 0 -- the second ending of the repeat. A phrase can be called as many times as needed. It's still defined after it is called, and you need not re-define it. Defined phrases have many more uses than besides repeats. If you want to change envelope settings back and forth within a song, you can define the envelope settings and call them wherever needed. Any voice can call a phrase from any other voice that has defined it. However, don't define several phrases at the beginning of a sid before any notes are played. It can result in a "clobber" error. A phrase really shouldn't be defined until the first time it's needed. Since we've run out of time tonight, tempo restrictions will be taken up at the next class. :)