DPLAYER NEWS #4 April 1986 This is the fourth news file for Sidplayer, the music system published in "All About The Commodore 64, Volume Two" by COMPUTE! Books. This news file offers many hints, tips, and suggestions on how to more easily create better sounding songs. The information presented here will be of interest to both novices and experienced users. Please keep in mind that the Sidplayer Editor is to be used only by those who have purchased Volume Two. The Editor is not a Public Domain program. This document is not intended to be a guide on how to use the Editor for people who have not purchased the book. The main part of this document consists of suggestions organized by command name. After these suggestions you will find some shorter sections that describe the symptoms of Master Composer Syndrome, encourage you to hook your computer up to a stereo, and offer some advanced techniques to ponder. TEM 1. The Editor lacks a feature to play just a given measure. Although a fast forward feature is available, it can still take a while to skip past part of a song. A faster way to skip over a part is to insert the command TEM 900 at the beginning of the part to be skipped, and then insert a TEM command for the correct tempo at the place you want to hear. When you play the song, the part to be skipped will be played even faster than is permitted by the fast forward feature, and you won't run a risk of getting a CLOBBER error (unless you use the fast forward feature as well). There are two restrictions to the use of this technique. If the part to be skipped contains thirty second notes, tempo 450 will have to be used instead. If the part uses utility durations, this technique cannot be used. 2. The tempo chart on page 285 is so handy, it may be worthwhile to photocopy the page for quick reference for when you enter a song. UTL 1. If you need to get a portamento glide that is longer than a whole note, you can always use the utility duration. This will permit a glide of any duration up to four seconds. VOL 1. It is strongly recommended that you not use volumes above level 12, except when you are using the triangle waveform which is naturally quieter. If you use volume levels above 12, especially with the pulse wave, the song may overpower the speaker on some televisions, causing the sound to be distorted, and thereby detracting from the quality of your song. Not everybody has their C64 hooked up to a nice stereo that can handle the volume. 2. You need to use the VOL command on only one voice. The master volume sets the volume for all three voices. If a VOL command is used on more than one voice at the same time, the VOL on the highest numbered voice is the one that will take effect. Usually the VOL and BMP commands are used only on voice one. 3. Be aware that a popping noise occurs when the master volume is changed by large amounts. Some people feel that the popping detracts from the song, and try to minimize the popping in their songs. To reduce the popping, try using smaller volume level changes and different positions for the volume changes. The sustain levels can also be adjusted to control the overall volume. BMP 1. As with the VOL command, use BMP in only one voice. If two voices use a BMP command at the same time, the volume will be bumped by two levels instead of one. 2. BMP can be used to fade out a song when the last measure or two are repeated. Some songs also use BMP to fade out the last note, but this creates a noticeable "stepping" effect in the volume as it changes. A better way to fade out a note is to use a long release (a large RLS value). HED and TAL 1. Remember that repeat loops cannot be nested. Be especially careful of this when you have a repeat loop that contains a phrase call, and the phrase also contains a repeat loop. 2. If at all possible, try to avoid using HED 0 for endless repetition. A song that does not end does not work very well with an autoplayer. DEF 1. Some songs contain several phrase definitions right at the beginning of each voice, which often set up waveforms and envelopes that are not used until later in the song. This may be convenient but it is not always a good practice. When Sidplayer has to process several commands before the first note, the chance of getting a CLOBBER error is increased. This error occurs when too many commands are placed between notes, and they cannot all be processed in one jiffy (one sixtieth of a second). The intended way for a phrase to be used is to define the phrase as it is played the first time, and then to call it when it needs to be played again later. See pages 300 to 304 for a complete explanation of phrases. F-M and FLT 1. Sometimes it can be handy when editing a song to play only one voice at a time. Unfortunately, this cannot be done if the voice contains a call to a phrase defined in a voice that is not being played. A way to get around this limitation is to play the voice that contains the phrase definition but to include the commands F-M N and FLT Y at the beginning of the voice. Selecting a filter mode of N (no mode) and passing the voice through the filter makes the voice inaudible. This allows you to play the voice so that the phrase gets defined, without hearing the voice itself. F-X 1. In addition to generating tones for music, the SID chip also picks up a lot of the "noise" from the circuitry inside the computer. This undesirable background noise can be significantly reduced on some computers by turning on the external filter input. To take advantage of this, just include an F-X Y command at the beginning of each song you create. The songs will be free of a lot of the background hiss when played. Other than making the song sound much cleaner, enabling the external filter input will not have any effect on the song. ATK 1. It is not always desirable to use a value of 0 for the ATK command. When all three voices have an attack rate of 0, and all three voices start playing new notes at the same time, sometimes the SID chip will not gate (start playing) the notes together, and one note will noticeably start to sound before the others. The phenomenon is sporadic, but does not occur with slower attack rates, so you can use ATK 1 to get around the problem. DCY 1. To minimize the "biting" effect of the volume falling from the attack peak to a much lower sustain level, a slower decay rate can be used. SUS 1. Unfortunately, the SID chip does not provide a volume control for each voice (the VOL command affects all three voices), but to some extent, the sustain level of a voice can be used to control the volume of a voice. 2. If one voice is playing a melody and other voices are supporting it by playing harmony, it is a good idea to have the SUS level for the harmony voices set at least one level lower than the sustain level for the melody voice. If they are equal, the harmony voices can overpower the melody voice. Setting their SUS levels lower makes the melody voice stand out, and generally the song will sound a bit nicer. RLS 1. As with the ATK command, it is a good practice to avoid using the value 0 with the RLS command. A release rate of 0 sometimes makes voices cut off unevenly. It is more noticeable when the song is played on a stereo instead of a television or monitor speaker. Values from 1 to 15 are recommended for a more pleasant effect. PNT 1. The release point, set by the PNT command, determines the number of jiffies from the end of a note that the note should start to release. Always remember that the release point must be less than the duration of the note being played, or the note will not be played properly. For example, in tempo 100 a sixteenth note is 9 jiffies long. If the release point is set to 12, the note will start to release as soon as it starts playing. It will never have a chance to complete its attack, and so will not be heard, or will be hardly audible. For this reason the release point is usually set around 4 or 5. If you have the release point set larger and have to play some shorter notes, it may be necessary to temporarily set the release point smaller for those notes. You can refer to the tempo chart on page 285 to determine the exact jiffy count for any note in any tempo. 2. If notes of longer durations are being played, a reason to use a larger release point is to create a more staccato effect. 3. Setting the release point to 0 means that notes played will never be released. This is the same thing as tying the notes together. Therefore, if you need to enter a lot of notes that are all tied together, for a legato effect, set the release point to 0 instead of entering a tie for each note. 4. If a voice contains alternating notes and rests of the same duration, such as a quarter note, quarter rest, quarter note, quarter rest sequence in a bass line, a shortcut can be used. The technique is combine the notes and rests into notes of equivalent total duration and then set the release point to make the release begin where the rest would normally begin. For example, let's say that the above quarter notes and quarter rests were played in tempo 100, so each note and rest was 36 jiffies long, and the release point was set at 4. Instead of entering quarter note and quarter rest pairs, you could enter half notes and set the release point at 40, where the 40 is 36 jiffies for the quarter rest and 4 jiffies for the normal release point of the quarter note. WAV 1. For some reason, pitches played using the pulse wave in octaves 0, 1, and some of 2 sound out of tune. It may be best to avoid using the pulse waveform when playing notes in the lowest octaves. 2. The pulse waveform can be combined with the triangle waveform to create a new and useful waveform type. Just enter the number 5 (4 for pulse plus 1 for triangle) to select the WAV TP command. The resultant waveform is especially useful for harpsichord effects. 3. The waveform combination SP is much quieter and therefore is not as useful. All other combinations seem to be inaudible. 4. Don't put a WAV command right before a rest. The release of a preceding note may continue into a rest, and a waveform change before the rest may clip the end of the note and be noticeable. Instead, just put the WAV command right before the next note to be played. P-W 1. Do not use the pulse wave with a pulse width less than 100. Notes played with a width much less than 150 are inaudible on some SID chips. 2. When using the TP waveform combination, be sure to have the pulse width set below 2048. The volume of the TP waveform decreases as the pulse width goes above 2000. Also set the width below 2048 when using waveform SP. P-S 1. Pulse width sweeping works by adding the pulse sweep value to the pulse width once each jiffy. The only problem with this is that with larger sweep rates, the pulse width can exceed 4095, in which case it wraps around and starts back at 0. This causes a very noticeable popping noise which can really detract from a song. To avoid the wraparound you can use a slower sweep rate or set the pulse width lower (or higher if you are sweeping backwards). If you want to keep the same pulse width and sweep rate, first determine on which notes the wraparound occurs. These will be the notes with the longest durations. Then take each note which causes popping, divide it into two halves tied together, and insert a P-S command between them with the same sweep rate but the opposite direction. For example, if popping occurs on a half note when the sweep rate is 30, instead enter a quarter note tied to another quarter note of the same pitch, with a P-S -30 command between them. You will also need to enter a P-S 30 command after them to reset the direction of the sweep for the next note. SNC and RNG 1. Refer to pages 324 to 325 and 333 to 337 of Volume Two for the correct way to set up synchronization and ring modulation effects. VDP and VRT 1. For a more natural vibrato effect, you can change the vibrato depth while a note is playing. Just break the note into smaller notes of the same total duration, all tied together, and put VDP commands of increasing values between them. Again, remember to reset the depth back to the original value. 2. Be aware that the vibrato processing is done only for the duration of a note, and is not done when a rest is being played. When a note with a slow release rate is followed by a rest, the voice may continue to fade away during the first part of the rest. If vibrato is used on the note, it is sometimes noticeable that the vibrato all of a sudden stops as the note is fading away. To prevent this from happening, you can delete the rest, add its duration to the preceding note, and set the release point higher for that note as discussed in the above section on the PNT command. TPS 1. The SID chip cannot play pitches beyond octave 7, even when the TPS command is used. If you try to play a note above B7, the note will be played with the same pitch but in octave 7. Thus an E transposed to octave 8 will be played as an E in octave 7. To determine if a voice is being transposed out of range, watch the voice on KPLAY and see if the key goes off the right edge of the piano keyboard display and disappears. 2. It is possible for the SID chip to play pitches in octave -1 by using the TPS command with negative values, but this is rarely useful. AUX 1. When using the AUX command to change the color of the piano keys in KPLAY, do not use values outside the range of 0 to 15. Values larger than 15 do not give you any new colors, and songs using larger values may forfeit compatibility with future editions of players. Sidplayer News Part 4 continues in SIDNP2.DOC