ArcSyn User Manual: Oscillator Waves
- All oscillator waveforms are generated at an oversampling rate of at least 4X.
- Oscillator waveforms which can be shape-modulated are indicated with a [*] symbol.
- The highest frequency which can be produced by an Oscillator is 12,555Hz, which is MIDI note 128. The lowest frequency is unlimited - the more negative modulation that is applied, the lower the frequency.
- Some waveforms, including the SYNC and SAW-TRI waves, use a type of 'adaptive' anti-aliasing which uses more CPU power than other waves.
The most useful analogue synthesizer waveform. Every synthesizer has one, even the Practical Electronics Minisonic Mk. 1 DIY project, which is just as well as it was the ONLY waveform it generated. ArcSyn's SAW produces no audible aliasing anywhere in its range. It ramps 'up' like most analogue oscillators, although that makes no difference to the way it sounds. No SHAPE adjustment.
The second most useful waveform. Can be adjusted between 50% and 99% width. 1% to 49% is not used as it sounds exactly the same - this way, 50% is easier to find (just set the shape control to zero) and the shape can be adjusted with twice as much precision.
The third most useful waveform? Good for pure, flute-like or whistling sounds. ArcSyn's triangle waveform is completely free of any audible aliasing. No SHAPE adjustment.
The simplest possible waveform. Has only one harmonic. No SHAPE adjustment.
A pulse with positive and negative peaks. This waveform is rarely available on hardware synths. When set to 0% shape, it produces a square wave, at 50% it produces what is effectively a 3-step RAMP and at maximum (about 99%) it produces a very thin bipolar pulse.
7. DOUBLE PULSE*
A pulse with alternating positive and negative peaks, this waveform has the same harmonic content as two square waves with a (variable) phase offset.
8. SAW HARD SYNC
A 'slave' saw oscillator is synced to the 'master' oscillator frequency, that is every time the master oscillator resets the saw wave at the end of each cycle, the slave oscillator is also reset. The frequency of the slave oscillator can be adjusted between between equal to the master oscillator frequency at 0% shape to 16 times (4 octaves above) the base frequency at 100% shape.
•The Sync waves use a different type of anti-aliasing to the other analogue waveforms, a type of 'adaptive oversampling' in which the wave, already oversampled by 4X is further oversampled by a factor of 32X when necessary, giving a total oversampling of 128X. This means that these waves use more CPU power.
9. SAW SOFT SYNC
The same as the Saw Hard Sync except the slave oscillator only resets if it is in the first half of its cycle when the master oscillator resets.
10. SAW CEM3140 SYNC
The same as the Saw Hard Sync except the slave oscillator resets to the start of its cycle if it is in the first half of its cycle, but resets to the halfway-point of its cycle if it is in the second half. This behaviour is modelled after the CEM1340 oscillator IC. I don't think it has ever been used except in the E&MM (Electronics and Music Maker) magazine Spectrum synthesizer DIY project.
11. SQUARE HARD SYNC
12. SQUARE SOFT SYNC
13. SQUARE CEM3140 SYNC
The same as the corresponding Saw Sync waves except using square waves.
14. CUT SAW*
Based on a schematic (circuit) design by Jorgen Bergfors. At a setting of 0% it produces a SAW wave, at 100% it produces a very thin bipolar pulse. At intermediate settings it produces a cross between a SAW wave and a PWM PULSE wave, in which the PULSE wave 'cuts' into the SAW, hence the name.
15. WIDTH SAW*
16. FILTERED SAW*
A Saw wave processed through a -12dB/oct low-pass filter which tracks the oscillator pitch. The shape control adjusts the filter cutoff frequency.
17. STEPPED SAW*
A SAW wave quantised into steps like a staircase. Sounds surprisingly similar to an ordinary SAW wave—the reason for this is that each STEPPED SAW has just one harmonic less than an ordinary SAW wave—A 5-step STEPPED SAW has no 5th harmonic. The number of steps can be varied between 4 and 16—the reason for starting with 4 steps rather than 2 or 3, is because 2 would just be an ordinary SQUARE wave and 3 would be the same as the BIPULSE wave set to 50% SHAPE.
A wave which crossfades between a SQUARE wave (with all odd harmonics) and an even harmonic wave consisting of a SINE wave with a SAW wave 1 octave higher. This wave idea is based on a schematic (circuit) design by Jorgen Bergfors. The SHAPE control adjusts the crossfade between the ODD and EVEN waves.
19. COSINE SAW
A saw wave which has an s-shaped curve instead of a straight line for its slope. Has slightly more low end than a normal SAW. You can't have too many saws! No SHAPE adjustment.
20. RECTIFIED SINE
A full-wave rectified sine wave. Sounds subjectively one octave higher than the oscillator pitch. No SHAPE adjustment.
The thinnest-possible, fixed-width PULSE wave. Useful for adding a bright edge to programs. No SHAPE adjustment.
22. SAW + SQR SUBOCT*
A SAW wave with a SQUARE wave sub-octave. The SHAPE control adjusts the crosfade between the saw and sub-octave. At 100%, both waves are equal in level.
23. SAW + SINE SUBOCT*
A SAW wave with a SINE wave sub-octave. The SHAPE control adjusts the crosfade between the saw and sub-octave. At 100%, both waves are equal in level.
A wave which transitions between a saw and a square by hard clipping. Quite a subtle transformation. The halfway-point 50% SQUARE, 50% SAW is quite useful. The SHAPE control adjusts the shape. This wave uses a different anti-aliasing technique which uses more CPU power.
A wave which transitions between a TRIANGLE and a SAW by altering its symmetry. Sounds similar to low-pass filtering. The SHAPE control adjusts the shape. This wave uses a different anti-aliasing technique which uses more CPU power.
A wave which transitions between a TRIANGLE and a (99%) SQUARE by hard clipping. the SHAPE control adjusts the shape. This wave uses a different anti-aliasing technique which uses more CPU power.
27. FOLDED TRIANGLE*
A triangle wave fed through a waveshaper which folds it in on itself. Sounds like a cross between FM and SYNC. The SHAPE control adjusts the number of folds produced by the waveshaper.
28. SUPER SAW*
29. SUPER SQR*
30. SUPER TRI*
8 waves with variable detuning. The detuning algorithm uses a combination of equal and random offsets to try and create an optimally random arrangement. The SHAPE control adjusts the amount of detuning.
31. SUPER SAW OCT*
32. SUPER SQR OCT*
4 octaves of waves with variable detuning. The octaves are all lower than the oscillator's basic pitch. The SHAPE control adjusts the amount of detuning.
33. SAW SUBOCTS*
34. SQR SUBOCTS*
These waves produce phase-locked multiple sub-octave waveforms like those produced by an old divide-down string machine or organ. The waves are always normalised to the highest-possible level. The SHAPE control adjusts the number of octaves selected from 2 to 9. Because these waves always divide the oscillator pitch down, they often sound better at higher octave settings.
35. FM SAW*
36. FM SQUARE*
37. FM BELL*
38. FM PI*
39. FM 9*
Fixed ratio, variable index (depth) FM waveforms. A shape setting of 0% produces a pure sine wave with no FM harmonics at all. The SHAPE control adjusts the depth of FM.
40. FM CROSSFADE-1*
41. FM CROSSFADE-2*
Fixed ratio, fixed index (depth) FM waves which cross-fade from one ratio to another. The second one has more inharmonic (out of tune) ratios. The SHAPE control adjusts which ratio is selected.
42. FM SWEEP*
Variable ratio, fixed index (depth) FM. The Sweep waveform is continuously variable. The SHAPE control adjusts the FM ratio from 1:1 to 1:32.
43. FM STEP*
Variable ratio, fixed index (depth) FM waves. The Sweep waveform is continuously variable, the Stepped waveform is limited to fixed simple FM ratios like 1:1, 1:2 and so on. The SHAPE control adjusts the FM ratio from 1:1 to 1:32.
44. HARMONIC SWEEP*
A single SINE harmonic which can be crossfaded from the 1st harmonic up to the 32nd harmonic. The SHAPE control adjusts which harmonic is selected.
45. HARMONICS* 
A set of waveforms consisting of 8 equal-level SINE harmonics. Unlike wavetables, these waveforms can include inharmonic (out of tune) components. The SHAPE control adjusts which set of harmonics is selected.
46. SUB-HARMONIC SWEEP*
A SQUARE wave at the oscillator frequency along with another square wave which can step through 32 sub-harmonics (divisions of the oscillator pitch). The SHAPE control adjusts the division ratio from divide by 2 to divide by 32.
47. SUB-HARMONICS* 
A set of 4 sub-harmonic (divisions of the oscillator pitch) SQUARE waves in 32 preset divisions. These waves usually sound better when tuned in higher octaves like +3 or +4. The SHAPE control adjusts which set of sub-harmonics is selected.
48. FORMANTS* 
A set of 16 waveforms which have strong resonant peaks at fixed frequencies which do not track the oscillator pitch. Threre are 16 sets of resonant frequencies. The first 8 are based on human vocal sounds. These waveforms can be very bright and penetrating and often sound better when LP filtered. The SHAPE control adjusts which set of formants is selected.
49. PULSE DIVIDER*
A SQUARE wave with every Nth cycle missing. Adds a sub-harmonic character to the basic square wave. The SHAPE control adjusts the division ratio from divide by 2 to 16.
50. QUAD XOR*
4 detuned SQUARE waves fed into a 4-input ring modulator. Produces a sound with more harmonic content than present in the basic waves. The SHAPE control adjusts the amount of detuning.
51. SINE ALIAS*
A SINE wave fed into an audio-rate sample-and-hold module to deliberately produce aliasing. The SHAPE control varies the frequency of the sample-and-hold oscillator.
A deliberately simple and crude wavetable which makes a feature out of it's defects :-) The waves switch rather than crossfade and are limited to 16 steps. The SHAPE control adjusts which wave is selected. There are 64 different waves.
53. RING MOD-1*
Two SQUARE waves ring-modulated (multiplied) together. One is fixed at the oscillator pitch, the SHAPE control adjusts the other from -1 to +1 octaves.
54. RING MOD-2*
A SINE wave and a SQUARE wave ring-modulated (multiplied) together. One is fixed at the oscillator pitch, the SHAPE control adjusts the other from -1 to +1 octaves.
55. RING MOD-3*
A SQUARE wave at the oscillator pitch ring-modulated (multiplied) with another SQUARE wave which can be adjusted over the full oscillator pitch range but is otherwise fixed, in other words it doesn't track the keyboard input.
56. RESONANT SAW*
57. RESONANT SQUARE*
58. RESONANT SINE*
3 waves which are a cross between HARD SYNC and RING MODULATION. The waves are enveloped by a sine shape to 'hide' the hard reset caused by the SYNC. The SHAPE control adjusts the frequency offset of the (virtual) 'slave' oscillator from 1 to 16 times.
59. SAW CHORDS* 
60. SQR CHORDS* 
32 different 4-voice chords using either SAW or SQUARE waves. • In the display, M means major and m means minor.
61. WHITE NOISE
ArcSyn's white noise has 32 bit precision, is 4X oversampled, level-compensated and even anti-aliased! No SHAPE adjustment.
62. PINK NOISE
High quality pink noise. Pink noise has equal energy per octave so is less bright and more "natural" sounding than white noise. Useful for classical synthesised surf and wind noises. No SHAPE adjustment.
63. RED NOISE
Deep, rumbling noise with a lot of low end and a slightly grainy character. No SHAPE adjustment.
64. VIOLET NOISE
'Differentiated' white noise. A bright, thin noise with very little low end. No SHAPE adjustment.
65. 1-BIT NOISE
Noise which randomly flips between +1 and -1 at the oscillator pitch. Produces a grainy, 'digital' noise character like an old arcade machine or 80's computer sound chip. No SHAPE adjustment.
66. BITWRAP NOISE*
Complicated digital-sounding aliasing noise produced by wrapping 8 counters which run much faster than the oscillator pitch. The fact that the counters go in and out of step with each other produces a constantly-shifting tone and level in the resulting noise.
67. LINEAR NOISE
Soft, pitched digital noise produced by sampling white noise at the oscillator pitch then connecting the samples together with straight lines, somewhat like a 'random triangle wave'. No SHAPE adjustment.
68. TUNED NOISE*
A SINE wave oscillator frequency-modulated by LINEAR NOISE. The SHAPE control adjusts the depth of pitch modulation. Even when set to 0% there is still some modulation to avoid the resulting sound turning into a plain SINE wave.
69. BIT PATTERN* 
Semi-random waveforms which use digital bit-manipulating techniques to produce complicated 8 bit patterns of varying length based on the basic oscillator pitch. These waveforms are fully anti-aliased. As they divide the oscillator pitch down many times, they usually sound more 'musical' in higher octaves. setting the oscillator pitch to +2, +3 or +4 is often a good idea.
70. CHAOTIC NOISE*
Noise produced using a variation on the Lorenz chaotic formula. It has a pitched element which follows the oscillator pitch but also a noisy element. Higher SHAPE settings produce a harsher noise.
71. CRACKLE NOISE*
Noise with a 'digital' character which sounds like a crackling noise at low SHAPE settings and white noise at high settings.
72. DIGITAL NOISE*
Noise with a 'digital' character which is similar to the classic 'VCO modulated by a random sample-and-hold' patch at low SHAPE settings and white noise at high settings.