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┌┬───────────────────────────┬┐
││ FM-Edit: Voice parameters ││
└┴───────────────────────────┴┘
Function key usage Mouse
F1 - Display this help information. [Help]
F2 - Go to Setup screen. [Setup]
F3 - Exit program. [Exit]
F4 - Zero all voice parameters. [Zero]
F6 - Return to Voice bank screen. [Bank]
F7 - Play a note (or song). See general help. [Play]
F8 - Turn off any notes sounding. [Quiet]
F9 - Decrease value of current field. <left button>
F10 - Increase value of current field. <right button>
PgUp - Select previous voice. [Prev]
PgDn - Select next voice. [Next]
Home - Move to first screen cell (Voice #).
Alt-F2 - Toggle MIDI thru mode (IN sent to OUT), [Thru]
default is on. (more)
Alt-F3 - Push to DOS. [Push]
Alt-F7 - Load standard MIDI file. [MFF]
Alt-F8 - Set song position. [Pos]
Alt-R - Set other cells in row the same as
current cell.
This screen allows the viewing or modification of the makeup of individual
voices. The relationships among the various parameters are very complex,
and a good deal of experimentation is required to learn how they work. The
best approach is to take specific voices and slightly modify parameters to
observe the effects. Another approach is to begin with the simplest output,
a continuous sine wave, and start changing and adding.
The left side of the screen contains basic parameters which affect the
overall sound, such as LFO usage. The right side controls the basic sound
generation components, called "operators", of which there are 4. Each
operator can be thought of as an oscillator, some used as "carriers" (or
tone generators), and some used as "modulators" (which vary the frequency of
a carrier or another modulator). There are 8 predefined "algorithms", or
ways of combining the 4 operators as carriers and modulators. Select any
voice and change "Algorithm #"; the possible layouts will be displayed at
the bottom right of the screen. The output of operator 1 may also be fed
back into its input to generate a richer output sound.
┌─────────────────────────┐
│ Common voice parameters │
└─────────────────────────┘
- Voice Number: Indicates the current voice number within the previously
selected bank of 48 voices. Changing the voice number will select a new
voice and display its parameters for viewing or editing.
- Voice Name: A 7-character descriptive name for the voice.
- LFO Speed: The speed of the Low Frequency Oscillator. Note that here,
the LFO speed is specified from 0 to 255, corresponding to the 0 to 127
range on the configuration screen (i.e., it is multiplied by 2).
- LFO Load mode: Determines whether LFO parameters defined here will
replace those set in the configuration when selecting this voice. Beware
of this side-effect when load mode is on.
- LFO Sync mode: If "on", causes the LFO waveform to start its cycle at the
time a note begins. This produces a more predictable sound when the LFO
is operating at very low frequencies.
- LFO Waveform: Specifies the waveform type to be used by the LFO:
Triangle, Ramp, Square, or Sample & Hold. Triangle: rises and falls at a
uniform (linear) rate. Ramp: rises at a uniform rate to a peak and then
drops immediately. Square: alternates between steady max and min levels.
Sample & Hold: random levels.
- AM Depth: Specifies the maximum depth of amplitude modulation (tremolo)
applied to all voice outputs (min: 0, max: 127).
- AM Sensitivity: Limits the effect of LFO amplitude modulation on this
voice (min: 0, max: 3). If either AM Depth or Sensitivity is 0, no
amplitude modulation is applied.
- PM Depth: Specifies the maximum depth of pitch modulation (vibrato)
applied to all voice outputs (min: 0, max: 127).
- PM Sensitivity: Limits the effect of LFO pitch modulation on this voice
(min: 0, max: 7).
- Transpose: Permits pitch transposition of the voice from -128 to +127
half steps.
- Feedback level: Specifies the amount of feedback from the output of
operator 1 to its input (min: 0, max: 7).
- Algorithm #: Selects one of the 8 operator combinations (numbered 0 to 7)
to use in sound generation for this voice.
- Pitchbender range, Portamento time, Mono/Poly mode, PMD controller: See
Configurations help for descriptions of these voice function parameters.
- Copy from voice, bank: Allows copying another set of voice parameters
into the current voice. When a value is entered into either cell, the
indicated voice is immediately copied. If either cell is blank, the
current voice or bank number is assumed for the missing value.
┌─────────────────────┐
│ Operator parameters │
└─────────────────────┘
- Status: May be "on" or "off", specifying whether the operator is active.
An operator may also be deactivated by setting Total level to 0.
- Multiple: Specifies the operator frequency relative to keyboard pitch.
For a value of n, where n is 1 to 15, the keyboard pitch is multiplied by
n. If n is 0, the keyboard pitch is divided by 2.
- Inharmonic: Used in conjunction with Multiple to specify a non-integral
multiplier to compute the operator frequency. Multiply the resultant
frequency from above by 1.00, 1.41, 1.57, or 1.73, for Inharmonic values
of 0, 1, 2, or 3, respectively.
- Detune: Permits slight detuning of the operator frequency in increments
of 1/64th of a half step (min: -3, max: +3).
- Attack rate: Determines the rate of speed at which the output will reach
its maximum level after a key is pressed. For a range of 0 to 31, 31 is
the fastest attack (instantaneous).
- Decay rate 1: Specifies the rate of decay in output level from the time
that it reaches the maximum level until it drops to the Sustain level
(slowest: 0, fastest: 31).
- Sustain level: Specifies an intermediate output level between the first
and second decays (min: 0, max: 15).
- Decay rate 2: Specifies the rate of decay from the point the output level
drops to the Sustain level following the first decay (slowest: 0, fastest:
31). If 0, the output remains at the Sustain level until the key is
released.
- Release rate: Specifies the decay rate to 0 output level from the point
that the key is released (slowest: 0, fastest: 15). While in this
program, use F8 to stop a note from sounding if it has no release decay
rate; otherwise, it will sound indefinitely.
- Total level: The maximum output level of this operator (min: 0, max:
127).
- Kbd rate scaling depth: Determines the extent to which increasing
keyboard pitch affects attack/decay characteristics (min: 0, max: 3).
Greater depth causes a more pronounced increased in attack/decay rates as
pitch increases.
- Kbd lvl scale type: Keyboard level scaling type (0-3). Determines the
relationship between keyboard pitch and operator output level. Type 0:
linear decrease in output with an increase in pitch. Type 1: like type 0
but non-linear. Type 2: minimum output at lower pitches, increasing
through middle, and leveling at high end. Type 3: like type 2 but with
sharper output increase in middle register.
- Kbd lvl scale depth: Keyboard level scaling depth. Amount of output
scaling applied for given scaling type (min: 0, max: 15).
- Vel sens - total level: Specifies the relationship between key velocity
and output level (min sensitivity: 0, max: 7).
- Vel sens - attack rate: Specifies the relationship between key velocity
and attack rate (min sensitivity: 0, max: 3).
Note: When a voice is zeroed (via F4), not all numeric parameters will
actually appear as zero. In some cases the maximum and minimum range
values are reversed in the internal representation, so zeroing will select
the maximum "effect" of a parameter.
┌───────────────┐
│ FM Background │
└───────────────┘
The effect of Frequency Modulation is to make a sound richer in "partial"
components. Partials are sometimes called overtones or harmonics, depending
on the context. Natural sounds produced by conventional musical instruments
consist of combinations of many of these partial frequencies, in addition to
the stated pitch that an instrument is playing. Often, these partials
change in relative intensity over the time that a note is sounding. The
partial makeup and the way the partials change give each instrument its
characteristic sound. By using frequency modulated signals, and varying the
modulation over time, the frequency makeup of many natural sounds can be
simulated. Of course, the technique may also be used to create entirely new
sounds.
There are specific mathematical relationships which describe exactly what
happens in FM, but as an example, assume a simple sine wave carrier of
frequency c. A sine wave modulator of frequency m will cause the carrier to
fluctuate around the original frequency, c. The resultant sound can be
described in terms of at least 3 partial frequencies: c, c+m, and c-m.
Depending on the amplitude of the modulator, additional significant "side
frequencies" are generated at c, plus and minus multiples of m. If the
carrier or modulator have multiple frequency components to begin with, each
modulator frequency interacts with each carrier frequency in the same
manner, causing an "explosion" of new frequencies.
For detailed information on FM synthesis, refer to "Yamaha FM Theory and
Applications" by Chowning & Bristow. This is one of the most in-depth
studies of FM synthesis techniques available for musicians. Although
written primarily in terms of the Yamaha DX7, the same principles apply to
the design of voices for the FB-01.
--- Press F1 for general usage information ---