Exploring the Commodore 64 MOS Technology 6581 Sound Interface Device

0:00 Preamble
2:30 Triangle wave - curved due to non-linearity in 6581 amplifiers
3:45 Sawtooth wave - kink at zero crossing
3:57 Pulse wave with pulse width control
4:05 Two oscillators - pulse wave
4:35 Filter - low pass, pulse wave
5:09 Non-linearity (distortion) in 6581 filter
6:52 Filter - band pass
6:59 6581 filter cutoff characteristics
8:18 Filter - high pass
9:20 Filter - low pass + band pass
9:44 Filter - notch (low pass + high pass)
10:58 Filter - band pass + high pass
11:48 Filter - resonance
12:26 Filter - second harmonic distortion
13:43 Filter - two oscillators
15:54 Filter - three oscillators
17:41 Filter - high distortion
19:30 Waveforms - combined waveforms
19:58 Waveforms - combined waveform (triangle and sawtooth)
20:21 Waveforms - combined waveform (triangle and pulse)
22:35 Waveforms - combined waveform (sawtooth and pulse)
23:56 Waveforms - combined waveforms, pulse width control
25:01 Waveforms - combined waveform (triangle and sawtooth and pulse)
25:12 Waveforms - ring modulation (triangle * square)
25:17 Waveforms - ring modulation and sync
25:22 Waveforms - triangle sync
25:27 Waveforms - sawtooth sync
25:36 Waveforms - combined waveform ring modulation (triangle and pulse, square)
26:32 Waveforms - combined waveform (sawtooth and pulse) sync

Exploring the Commodore MOS Technology 6581 Sound Interface Device (SID) using a Behringer BCR2000 control surface.

Please see my other video on the 8580R5 as well as this one.

Filming by 3DMtunes:

The PC contains a HardSID card which is controlled by a custom piece of software. The Yamaha V50 keyboard is plugged into the PC using MIDI and sends MIDI note on and note off messages. The Behringer BCR2000 control surface is also plugged into the PC using MIDI and sends MIDI controller change (CC) messages. The custom software receives both types of messages and writes SID chip register changes to the HardSID card.

The functions on the BCR2000 knobs and buttons are as follows:

Top row (from left to right)

Filter cutoff frequency
Filter resonance
Filter mode
Volume

Buttons (top row from left to right)

Filter oscillator 1 on/off
Filter oscillator 2 on/off
Filter oscillator 3 on/off

Buttons (second row from left to right)

Oscillator 1 on/off
Oscillator 2 on/off
Oscillator 3 on/off

Second row (Oscillator 1 from left to right)

Coarse tune
Fine tune
Waveform
Pulse width
Attack
Decay
Sustain
Release

Third row (Oscillator 2 from left to right)

Coarse tune
Fine tune
Waveform
Pulse width
Attack
Decay
Sustain
Release

Fourth row (Oscillator 3 from left to right)

Coarse tune
Fine tune
Waveform
Pulse width
Attack
Decay
Sustain
Release