Pluck Class Reference
[Virtual Acoustics (a.k.a. Physical Modeling or Waveguide) Synthesis]
Plucked string synthesis.
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#import <Pluck.h>
Public Member Functions | |
| (id) | - init |
| Sent by the MKOrchestra only when a new MKSynthPatch has just been created and before its MKUnitGenerator connections have been made, as defined by the MKPatchTemplate. | |
| (id) | - noteOnSelf: |
| aNote is assumed to be a noteOn or noteDur. | |
| (id) | - noteUpdateSelf: |
| aNote is assumed to be a noteUpdate and the receiver is assumed to be currently playing a MKNote. | |
| (double) | - noteOffSelf: |
| aNote is assumed to be a noteOff. | |
| (id) | - noteEndSelf |
| Resest instance variables to default values. | |
| (id) | - preemptFor: |
| Preempts envelope, if any. | |
Static Public Member Functions | |
| (id) | + patchTemplateFor: |
| Returns a default template. | |
Protected Attributes | |
| double | freq |
| double | sustain |
| double | ampRel |
| double | decay |
| double | bright |
| double | amp |
| double | bearing |
| double | baseFreq |
| int | pitchBend |
| double | pitchBendSensitivity |
| double | velocitySensitivity |
| int | velocity |
| int | volume |
Detailed Description
Plucked string synthesis.Pluck implements a Plucked string with fine-tuning of pitch and dynamics, as described in Jaffe/Smith, and Karplus/Strong, "The Music Machine", MIT Press, 1989. This is a type of "virtual acoustic" synthesis (also called "physical modeling" or "waveguide synthesis".)
Pluck creates a sound suggesting a struck or plucked string. It uses a delay line to represent the string. The lower the pitch, the more delay memory it needs. The implication is that a passage with many low notes may have problems running out of DSP memory. Pluck does dynamic allocation of its delay memory. This may result in some loss of memory over time due to DSP memory fragmentation.
Keep in mind that the highest frequency that Pluck can play is only 1300 Hz. for a sampling rate of 22050 and 2600 Hz for a sampling rate of 44100. (For the curious, this annoying limitation could be lifted if the MKSynthPatch were redesigned to be one giant UnitGenerator. The limitation comes in the pipeline delay, which is the tick size 16 samples).
Parameter Interpretation
amp - Amplitude. In the range 0.0:1.0. amp1 is a synonym for amp. Default is 0.1. Note that this parameter applies only to the initial pluck. Attempts to change the amplitude after the pluck have no effect. Also, note that the resultant amplitude may be lower than a comparable setting in other SynthPatches, due to the indeterminate nature of the noise used for the attack. Default is 0.1.
ampRel - Time in seconds at end of note (after noteOff) for string to damp to -60dB of original amplitude. Default is 0.15.
bearing - Left/right panning of signal. In range -45.0:45.0. -45.0 is far left. Default is 0.0.
bright - Brightness of the pluck. In range 0.0:1.0. 1.0 is very bright. Default is 0.5.
controlChange - This parameter is the MIDI controller number to be affected. It is used in conjunction with the parameter controlVal, which provides the value the controller is set to. This SynthPatch uses MIDI volume (controller 7) to adjust output volume as an attenuation of the final output signal. The default for MIDI volume is 127.
controlVal - See controlChange.
decay - Time constant of additional decay beyond the natural decay of the string. A value of 0.0 indicates no additional decay. This value is given in units of t60. (t60 is the time for a note to decay to -60dB of its original amplitude.) Default is 0.0.
freq - Frequency in Hz. freq1 is a synonym for freq. Default is A440.
keyNum - The MIDI key number, an alternative to freq. If both freq and keyNum are present, freq, takes precedence. In the range 0:127.
lowestFreq - This parameter is used to warn the synthpatch what the lowest freq that may appear in the phrase will be so that it can allocate an appropriate amount of delay memory. It is only used in the first note of a phrase. Note that very low pitches use an awful lot of memory and may exceed the capacity of the DSP.
pickNoise - In seconds (duration of initial pick noise). Default is a period of time equal to one period at the fundamental frequency.
pitchBend - Modifies frequency (or keyNum) as a 14 bit integer. A value of MIDI_ZEROBEND (defined as 0x2000 in <mididriver/midi_spec.h>) gives no bend. 0 is maximum negative bend. 0x3fff is maximum positive bend. See TuningSystem class for details. May give unexpected results when combined with frequency envelopes. Default is MIDI_ZEROBEND.
pitchBendSensitivity - A value of 0.0 means pitchBend has no effect. A value of 1.0 means pitch bend corresponds to plus or minus a semitone. Larger values give larger pitch deviation. Default is 3.0.
sustain - In range 0.0:1.0. 1 means "sustain forever". 0 is the default and gives a moderate sustain.
velocity - A MIDI parameter. In range 0:127. The default is 64. Velocity scales amplitude by an amount deteremined by velocitySensitivity. Note that Pluck uses this parameter to scale brightness as well as amplitude. In range 0:127. Default is 64.
velocitySensitivity - In range 0.0:1.0. Default is 0.5. When velocitySensitivity is 0, velocity has no effect.
Member Function Documentation
| + (id) patchTemplateFor: | (MKNote *) | currentNote |
Returns a default template.
currentNote is ignored.
- Parameters:
-
currentNote is an MKNote instance.
- Returns:
- Returns an id.
Reimplemented from MKSynthPatch.
| - (id) init |
Sent by the MKOrchestra only when a new MKSynthPatch has just been created and before its MKUnitGenerator connections have been made, as defined by the MKPatchTemplate.
- Returns:
- Returns an id. A subclass may override the init method to provide additional initialization. A return of nil aborts the creation and frees the new MKSynthPatch. The default implementation does nothing and returns the receiver.
Reimplemented from MKSynthPatch.
| - (id) noteOnSelf: | (MKNote *) | aNote |
aNote is assumed to be a noteOn or noteDur.
This method triggers (or retriggers) the MKNote's envelopes, if any. If this is a new phrase, all instance variables are set to default values, then the values are read from the MKNote.
- Parameters:
-
aNote is an MKNote instance.
- Returns:
- Returns an id.
Reimplemented from MKSynthPatch.
| - (id) noteUpdateSelf: | (MKNote *) | aNote |
aNote is assumed to be a noteUpdate and the receiver is assumed to be currently playing a MKNote.
Sets parameters as specified in aNote.
- Parameters:
-
aNote is an MKNote instance.
- Returns:
- Returns an id.
Reimplemented from MKSynthPatch.
| - (double) noteOffSelf: | (MKNote *) | aNote |
aNote is assumed to be a noteOff.
This method causes the MKNote's envelopes (if any) to begin its release portion and returns the time for the envelopes to finish. Also sets any parameters present in aNote.
- Parameters:
-
aNote is an MKNote instance.
- Returns:
- Returns a double.
Reimplemented from MKSynthPatch.
| - (id) noteEndSelf |
Resest instance variables to default values.
- Returns:
- Returns an id.
Reimplemented from MKSynthPatch.
| - (id) preemptFor: | (MKNote *) | aNote |
Preempts envelope, if any.
- Parameters:
-
aNote is an MKNote instance.
- Returns:
- Returns an id.
Reimplemented from MKSynthPatch.
Member Data Documentation
- (double) freq [protected] |
Frequency.
- (double) sustain [protected] |
Sustain parameter value
- (double) ampRel [protected] |
AmpRel parameter value.
- (double) decay [protected] |
Decay parameter value.
- (double) bright [protected] |
Brightness parameter value
- (double) amp [protected] |
Amplitude parameter value.
- (double) bearing [protected] |
Bearing parameter value.
- (double) baseFreq [protected] |
Frequency, not including pitch bend
- (int) pitchBend [protected] |
Modifies freq.
- (double) pitchBendSensitivity [protected] |
How much effect pitch bend has.
- (double) velocitySensitivity [protected] |
How much effect velocity has.
- (int) velocity [protected] |
Velocity scales bright.
- (int) volume [protected] |
Midi volume pedal
The documentation for this class was generated from the following file:
