OPLL FM synthesis instrument editor

the OPLL FM editor is divided into 5 tabs:

• FM: for controlling the basic parameters of FM sound source.
• Macros (FM): for macros controlling algorithm, waveform and feedback.
• Macros (OP1): for macros controlling FM parameters of operator 1.
• Macros (OP2): for macros controlling FM parameters of operator 2.
• Macros: for other macros (volume/arp/pitch/patch).

FM

the OPLL synthesizer is two-operator, meaning it takes two oscillators to produce a single sound.
however, unlike the other FM chips, only one custom patch may be set at a time, shared among all 9 channels.

but don't worry! there also are 15 preset patches that you may select at any time.

these apply to the instrument as a whole:

• Feedback (FB): determines how many times operator 1 returns its output to itself (0 to 7).
• Sustain (SUS): enables the sustain flag (sets the release rate to 5).
• DC (half-sine carrier): sets the waveform produced by carrier operator to half-sine.
• DM (half-sine modulator): sets the waveform produced by modulator operator to half-sine.
• preset dropdown: selects OPLL preset instrument.
• this is the selector for the preset patches I mentioned before.
• once a preset patch is selected, only the volume is configurable.
• only one user-specified patch may be applied at a time!

if you select the special Drums patch, you may use the instrument in Drums mode of OPLL. an extra setting also appears:

• Fixed frequency mode: allows you to set a fixed frequency for the drum channels.

these apply to each operator:

• the crossed-arrows button can be dragged to rearrange operators.
• Amplitude Modulation (AM): makes the operator affected by LFO tremolo.
• Envelope generator sustain flag (EGS): when enabled, value of Sustain Level is in effect.
• Attack Rate (AR): determines the rising time for the sound. the bigger the value, the faster the attack (0 to 15).
• Decay Rate (DR): determines the diminishing time for the sound. the higher the value, the shorter the decay. it's the initial amplitude decay rate (0 to 15).
• Sustain Level (SL): determines the point at which the sound ceases to decay and changes to a sound having a constant level. the sustain level is expressed as a fraction of the maximum level (0 to 15).
• Release Rate (RR): determines the rate at which the sound disappears after note off. the higher the value, the shorter the release (0 to 15).
• Total Level (TL): represents the envelope’s highest amplitude, with 0 being the largest and 63 (decimal) the smallest. a change of one unit is about 0.75 dB.
• in the case of the second operator, it goes from 0 to 15 instead.
• Key Scale Level (KSL): also known as "Level Scale". determines the degree to which the amplitude decreases according to the pitch.

• Envelope Scale (KSR): also known as "Key Scale". determines the degree to which the envelope execution speed increases according to the pitch.
• Frequency Multiplier (MULT): sets the coarse pitch offset in relation to the note (0 to 15). 0 is -1 octave, 1 is 0 octaves, 2 is 1 octave, 3 is 1 octave 7 semitones, and so on.
• note that values 11, 13 and 14 behave as 10, 12 and 12 respectively.
• Vibrato (VIB): makes the operator affected by LFO vibrato.

macros

these macros allow you to control several parameters of FM per tick.

FM Macros

all parameters are listed above.

OP1-OP4 Macros

all parameters are listed above.

Macros

• Arpeggio: pitch change sequence.
• Patch: changes the playing preset mid-note.
• through use of this macro, you may unlock different glitched sounds. useful for distortion guitars!
• Pitch: fine pitch.
• Relative: when enabled, pitch changes are relative to the current pitch.
• Phase Reset: restarts all operators and resets the waveform to its start.

links

FM instrument tutorial: A great starting point to learn how create and work with FM sounds. this was made for DefleMask, but all the same principles apply.