zynaddsubfx

ZynAddSubFX open source synthesizer
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lfo.txt (2648B)


      1 LFO
      2 ---
      3 :author: Paul Nasca
      4 
      5 Introduction
      6 ~~~~~~~~~~~~
      7 
      8 "LFO" means Low Frequency Oscillator.
      9 These oscillators are not used to make sounds by themselves, but they change
     10 some parameters (like the frequencies, the amplitudes or the filters).
     11 
     12 The LFOs have some basic parameters:
     13 
     14 * *Delay*: This parameter sets how much time it takes since the start of the
     15            note to the start of the LFO.
     16 * *Start Phase*: The position that a LFO will start at . 
     17 * *Fade In*: This parameter sets how much time it takes to ramp up to full depth after delay
     18 * *Fade Out*: This parameter sets how much time it takes to ramp down at note release
     19 * *Lowpass*: frequency of a lowpass filter applied to the lfo when usong square or random oscillator shape
     20 * *Frequency*: How fast the LFO is (i.e. how fast the parameter is controlled by
     21                the LFO changes)
     22 * *Numerator&Denominator*: Frequency can also be set relative to global Tempo (BPM)
     23 * *Depth*: The amplitude of the LFO (i.e. how much the parameter is controlled
     24            by the LFO changes)
     25 
     26 image:images/lfo0.png[]
     27 
     28 Another important LFO parameter is the shape.
     29 There are many LFO Types according to the shape.
     30 ZynAddSubFX supports the following LFO shapes:
     31 
     32 image:images/lfo1.png[]
     33 
     34 Another parameter is the LFO Randomness.
     35 It modifies the LFO amplitude or the LFO frequency at random.
     36 In ZynAddSubFX you can choose how much the LFO frequency or LFO amplitude
     37 changes by this parameter.
     38 In the following images, there are shown some examples of randomness and how it changes
     39 the shape of a triangle LFO.
     40 
     41 image:images/lfo2.png[]
     42 
     43 Other parameters are:
     44 
     45 * *Continuous mode*: If this mode is used, then the  LFO will not start from "zero" on each new note, but it will be continuous. This is very useful if you apply on filters to make interesting sweeps.
     46 * *Stretch*: It controls how much the LFO frequency changes according to the
     47 note's frequency.
     48 It can vary from negative stretch (the LFO frequency is decreased on higher
     49 notes) to zero (the LFO frequency will be the same on all notes) to positive
     50 stretch (the LFO frequency will be increased on higher notes).
     51 
     52 User Interface
     53 ~~~~~~~~~~~~~~
     54 
     55 In ZynAddSubFX, LFO parameters are shown as:
     56 
     57 image:images/uilfo.jpg[]
     58 
     59 These parameters are:
     60 
     61 * *Freq*: LFO Frequency
     62 * *Depth*: LFO Depth
     63 * *Start*: LFO Start Phase - 
     64 If this knob is at the lowest value, the LFO Start Phase will be random.
     65 * *Delay*: LFO Delay
     66 * *F.In*: Fade In
     67 * *F.Out*: Fade Out
     68 * *LP*: Lowpass
     69 * *A.R.*: LFO Amplitude Randomness
     70 * *F.R.*: LFO Frequency Randomness
     71 * *C.*: LFO Continuous Mode
     72 * *Str.*: LFO Stretch - in the image above the LFO stretch is set to zero