twisted electrons TherapSID User manual

TherapSID
USER MANUAL
Note: All functions apply to MKII and MKIII
May 2nd 2023
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Thanks! Overview
Thank you for adopting TherapSID, the ultimate SID synth!
About the SID chip:
The MOS Technology 6581/8580 SID (Sound
Interface Device) is the built-in Programmable
Sound Generator chip of Commodore's CBM-II,
Commodore 64, Commodore 128 and Commodore
MAX Machine home computers. It was one of the
first sound chips of its kind to be included in a
home computer prior to the digital sound
revolution.
Read more: http://en.wikipedia.org/wiki/
MOS_Technology_SID
I want to express my gratitude to several people who have
made TherapSID what it is. First and foremost, a special
thanks goes out to Windfisch for completely overhauling the
code and providing invaluable guidance and mentorship
throughout the process.
I would also like to thank Sequence7 and Oemsysadm for
their valuable feedback, I also want to extend my thanks to
ThomasJ for his exciting contributions to the project.
Thanks to Themis for all the testing and concept contributions
over the years and on going.
The TherapSID code is now open-source and available on
GitHub so please feel free to join the party!
https://github.com/twistedelectrons/TherapSID
Please use GitHub if possible to submit feature requests and bug reports!
Enjoy!
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Connectivity & Power (rear view)
TherapSID features from right to left
-Power input: TherapSID requires a centre positive DC voltage source of 15v
at least 200mA
-1/4” audio inputs and outputs for both chips (mono TS)
-MIDI input & output
-CV pitch input, Gate input (1/8” TS mono)
(only active when in monophonic mode)
-3 LFO override CV inputs (1/8” TS mono)
The Audio ins enables you to run any audio signal through the SID filter path.
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Presets
TherapSID comes preloaded with a total of 99
assorted presets get you started. It is important to
note that these presets are fully customisable and
can be modified to suit individual preferences.
It is worth mentioning that the presets were
developed specifically using the 6581 variant of the SID chip. Consequently,
there is a possibility that the presets may sound slightly different when used
with other SID variations.
Load
To change the preset, press the up/down buttons. Additionally, holding down
either button will result in accelerated scrolling in the corresponding direction.
The preset number will be displayed on the device's screen.
Save
It is possible to save the current sound to any preset slot by following these
steps:
-Activate the save mode by simultaneously pressing both preset up and down
buttons. The destination slot number will flash on the display.
-Choose the desired destination slot by pressing the preset up or down button.
-Save the current sound to the selected slot by pressing both preset up and
down buttons.
To cancel the save operation, press the reset button.
Preset Reset
Press reset to quickly load preset 1 - a useful preset to use as a starting point.
Preset Randomiser
To randomise the preset, simply hold down the reset button for a duration of 2
seconds.
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Voice Section
TherapSID’s 3 voices are laid out across the top half of the control panel. The
3 voice strips are identical in functionality, explained from left to right:
Waveforms
Each voice each consists of 4 waveforms:
Square,Triangle,Sawtooth and Noise.
Press the corresponding button to enable or disable a waveform (indicated by
LED).
Note: Multiple waveforms can be active at the same time.
Pulsewidth
The pw knob adjusts the duty cycle of the square waveform.
Note: this has no effect on the other waveforms, only square.
Tune
The tune knob transposes the voice in semitone increments. The tune ranges
from -12 to +12 semitones (2 octaves), indicated by the 7 segment LED
display.
Twelve ‘o clock knob position is zero.
Fine
The fine knob fine tunes the voice (+/-1 semitone range)
Twelve ‘o clock knob position is centre.
Master Volume
Hold filter mode and adjust the scrub knob to set the master volume. Lowering
the volume can reduce distortion when playing all voices at once.
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Paraphonic Mode
TherapSID has two voicing modes: unison and paraphonic. In unison mode, you can
play a single note at a time. This will trigger the 3 voices at once. Paraphonic mode
allows you to play up to three different notes simultaneously by splitting the 3 voices
into separate notes.
To activate paraphonic mode, hold a waveform button on voice 1 for two
seconds. The LED display will show "PA" to indicate that paraphonic mode is
active. Voices 2 and 3 will now mirror the parameters of voice 1. To switch
back to monophonic mode, hold a waveform button on voice 1 again for two
seconds. The LED display will show "OF" to indicate that monophonic mode is
active.
Fat Modes
TherapSID also supports a second SID chip, and there are several "Fat
Modes" available that allow you to take advantage of both chips. To switch
between the different Fat Modes, hold down the filter button and press the arp
mode button. The corresponding Fat Mode number will be displayed on the
screen. Note that some Fat Modes may exhibit different behaviours depending
on whether or not paraphonic mode is active.
Here are the available Fat Modes:
Mirror Mode (F1): Both chips have the exact same data transmitted.
Octave Mode (F2): Chip #1 is one octave above Chip #2.
Slightly Detuned Mode (F3): The two chips are slightly out of phase, creating
nice panorama effects.
Heavily Detuned Mode (aka Super Fat Mode) (F4): Six saw oscillators create
an incredibly thick and fat sound.
Polyphonic Modes (F5): When paraphonic mode is active, you can play up to
six notes at once, spread across both chips. When paraphonic mode is
deactivated, you can play two notes at once, each consisting of three voices in
unison.
Two-Voice/Three-Note Mode (F6, only available in paraphonic mode): This
mode enables you to play up to three notes at once, each consisting of two
voices (1 and 2). In this mode, you have access to the parameters of both
voice 1 and voice 2 to craft your sound.
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Auto Chord
To use the auto chord feature on the TherapSID, please follow these
instructions:
1- Hold down a chord on your MIDI keyboard.
2 - While still holding the chord, press and hold the arp mode and press the
retrig button to engage the auto chord feature.
To free up your hands for pressing buttons, we recommend using the sustain
pedal.
If you wish to disengage auto chord, simply repeat the same button presses
as before.
Note that if you activate auto chord without holding down any keys, the
TherapSID will select a chord from its built-in selection.
Glide
Adds glide aka portamento to the synth’s pitch.
More glide=longer portamentos/slides.
Sync
When set on voice1, Synchronizes the fundamental frequency of Oscillator 1
with the fundamental frequency of Oscillator 3, producing “Hard Sync” effects.
Varying the frequency of Oscillator 1 with respect to Oscillator 3 produces a
wide range of complex harmonic structures from Voice 1 at the frequency of
Oscillator 3. In order for sync to occur Oscillator 3 must be set to some
frequency other than zero but preferably lower than the frequency of Oscillator
No other parameters of Voice 3 have any effect on sync.
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Ring Mod
When set to voice 1 or 3, replaces the Triangle waveform output of that voice
with a “Ring Modulated” combination of Oscillators 1 and 3.
When set to voice 2, replaces triangle waveform output of voice2 with a “Ring
Modulated” combination of Oscillators 2 and 1.
Varying the frequency of Oscillator 1 with respect to Oscillator 3 produces a
wide range of non-harmonic overtone structures for creating bell or gong
sounds and for special effects. In order for ring modulation to be audible, the
Triangle waveform of Oscillator 1 must be selected and Oscillator 3 must be
set to some frequency other than zero. No other parameters of Voice 3 have
any effect on ring modulation.
Volume Envelopes - ADSR
The "attack" and "decay" of a sound have a great effect on the
instrument's sonic character. ADSR envelope is specified using four
parameters:
• Attack time is the time taken for initial run-up of level from nil to
peak, beginning when the key is first pressed.
• Decay time is the time taken for the subsequent run down from the
attack level to the designated sustain level.
• Sustain level is the level during the main sequence of the sound's
duration, until the key is released.
• Release time is the time taken for the level to decay from the
sustain level to zero after the key is released.
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Filter
The SID chips are equipped with a multimode resonant filter.
The filter is the analog section of the circuit and its warm/dirty sound
contributes to the authentic SID character.
Filter Modes
Press the filter button to toggle through the 4 filter states:
Off, Low Pass, Band Pass, High Pass, Low Pass+ High Pass (notch)
Cutoff
The cut knob adjusts the filter cutoff frequency
Resonance
The res knob adjusts the filter’s resonance
Note: The resonance is more or less pronounced depending on the type of
SID chip.
Filter Routing
One can connect or disconnect any of the three voices to and from the filter.
To do so, hold down the filter mode button, which will display the voices that
are currently connected to the filter. When a voice is connected, the waveform
LEDs will light up. To connect or disconnect a voice from the filter, press any
of its waveform buttons.
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Modulation (LFO)
TherapSID has 3 LFOs to bring your synth to life!
Note: the LFO values can also be transmitted as midi CCs to modulate other
MIDI capable instruments.
LFO Waveforms
There are 5 LFO types to choose from:
Square, Triangle, Saw, Noise and Env3 (ADSR envelope of voice 3).
-Move either of the 3 LFO’s depth or rate knobs to select that LFO.
-Press the lfo shape buttons to change the selected LFO’s shape.
You can also assign no shape at all by pressing a readily lit shape.
In this case the LFO’s depth knob becomes a manual controller.
Assigning LFOs to knobs
You can link any of the three available LFOs to the following knobs:
Filter Cutoff, Filter Resonance, Tune1, Tune2, Tune3, Fine1, Fine2, Fine3,
Width1, Width2, Width3, LFO Depth1, LFO Depth2, LFO Depth3, LFO Rate1,
LFO Rate2, LFO Rate3, Arpeggiator Scrub, Arpeggiator Range, Arpeggiator
Rate
Simply manipulate the desired knob and then press the chain button
of the LFO you wish to link to it. The chain LED will light up,
indicating that the LFO is now linked to the selected knob.
Should you need to unlink the LFO, simply press the link button
again, and the chain LED will deactivate. It's important to note that
you can link a single LFO to multiple knobs!
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