APCpp (Mono)¶
Description¶
APCpp stands for “Atari Punk Console plus plus”, i.e. the digital implementation of a popular electronics circuit with enhancements.
A little demotrack can be found here: https://soundcloud.com/taitekatto/apcpp-for-tbd
As with many simple Oscillators, the original hardware design is based on timerchips (two NE555 or one 556) https://de.wikipedia.org/wiki/NE555
To learn more about the original APC circuit please refer to: https://sdiy.info/wiki/Atari_Punk_Console
Here you can watch a video about how to build an (enhanced) APC in hardware and how it basically sounds: https://www.youtube.com/watch?v=1wTc4tqBpnw&feature=youtu.be
The enhancements for TBD are optional pitch-modulation, pulse-width-modulation, amplitude/ring-modulation, sinus waves for the oscillators and a volume-envelope. Details are explained with the parameters below.
Parameters¶
Section 1: “Atari-Punk-Console Oscillators / AM or PWM”
This is the section where you can find the two main oscillators and basic options on how to interact with them. Oscillators 1 and 2 are always modulating each other.
MOD 1 Frequency: Frequency of the optional modulator for OSC 1.
Frequency Osc 1: Frequency of OSC 1 - remember: this oscillator will always be modulated with the other Oscillator.
MOD 1 off/on: Apply modulation to OSC 1 or not.
MOD 1 is PWM n/y: You can choose between a kind of Pulse Width Modulation and Amplitude Modulation for OSC 1. PWM is applied with a sine wave, AM is applied with a rectangle here. The latter mode can result in interesting cut-effects to the sound. When the carrier wave is a sine the “PWM” is similar to a phase-modulation.
Smooth Oscillator 1 n/y: Typically for the APC the oscillator uses a rectangle wave and is modulated with the other oscillator with a kind of logical “not and” operation. In smoothed mode a sine wave is used instead and modulation with the other oscillator is amplitude modulation, also known as ring-modulation in case when the second oscillator is set to a sine wave.
Smooth Oscillator 2 n/y: See right above: “Smooth Oscillator 1 n/y”
MOD 2 is PWM n/y: You can choose between a kind of Pulse Width Modulation and Amplitude Modulation for OSC 2. PWM is applied with a sine wave, AM is applied with a rectangle here. The latter mode can result in interesting cut-effects to the sound. When the carrier wave is a sine the “PWM” is similar to a phase-modulation.
MOD 2 off/on: Apply modulation to OSC 2 or not.
Frequency Osc 2: Frequency of OSC 2 - remember: this oscillator always will be modulated with the other Oscillator.
MOD 2 Frequency: Frequency of the optional modulator for OSC 2.
Section 2: “Frequency Modulation”
Here additional pitch-modulation can be applied per oscillator
FreqMod 1 Amount / 0 to disable: When turned all the way to the left no pitch modulation will be applied to oscillator 1, all the way to the right up/down of a perfect fifth will be added in pitch.
Frequency-Modulation 1 Speed: Very slow to low audio-range frequency.
FreqMod 1 Square-Wave n/y: If set to on, oscillator 1 will be pitch-modulated by a square wave, a sine wave is used otherwise.
FreqMod 2 Square-Wave n/y: If set to on, oscillator 2 will be pitch-modulated by a square wave, a sine wave is used otherwise.
Frequency-Modulation 2 Speed: Very slow to low audio-range frequency.
FreqMod 2 Amount / 0 to disable: All the way to the left no pitch modulation will be applied to oscillator 2, all the way to the right up/down of a perfect fifth will be added in pitch.
Section 3: “VCA / Envelope”
Here the overall volume can be adjusted and an optional, loopable envelope generator applied to it.
Volume Amount: General volume and maximum amount of the volume envelope.
Please note: High settings, depending on the source-material may lead to distortion or even digital clipping. This is intentional to be able to amplify quieter sounds and also can be used in connection with the EG to obtain sounds that stay on a certain level for a longer period of time.
If in doubt, setting the volume to about the middle-position should be fine.
Use Envelope n/y: If activated the sound will be only audible when the volume envelope is triggered
Trigger Envelope: Triggers the envelope, which will loop if required.
Volume Attack: Modifies the time it takes to reach the peak in volume.
Volume Decay: Modifies the time for the sound to decay after the peak in volume had been reached.
Envelope Loop n/y: If on the envelope will trigger itself after it has reached its end.
Usage / Patch Ideas¶
This plugin is intended to let you experiment with all kinds of weird sounds.
To try out the original APC algorithm you should turn all options and modulations off, first.
Among other things, the APCpp can achieve self-playing sounds similar to those known from early SciFi movies like “Forbidden Planet”. For such sounds using the built in smooth options and adding echo and reverb or even a shimmer-verb is a good idea.
In general it’s always a good point to start with the two main oscillators alone. Remember that they are V/Oct. compatible, so in principle you can play tuned melodies. But the tuning is highly dependent on the modulation settings and the two oscillators modulate each other all the time, too, so some notes may be in tune, whereas others will not be, again experimenting is encouraged.
After you have set up the basic oscillators, choosing the suitable modulation may be the next step. In some cases, especially with “smoothed oscillators” and reverb, you may find sounds that remind you of “robotic vowels” when you change modulation frequencies on the fly.
If you want to make percussive sounds it’s good to make very dense basic sounds and to trigger them with a short envelope. On the other hand you can choose varying pad-like sounds by making basic sounds with slow evolution and use an envelope with a slow attack and a long decay.
It’s a good idea to attach the frequency of the main oscillators to CV-in and to use a CV-trigger for the envelope. For the pots of the TBD for instance tweaking the frequency or amounts of modulators can be interesting.