Genesis
In the beginning, there were lots of sounds. Now the sounds were diverse and interesting, but the patch bay was empty and silent, and the Spirit of Electronic Music was nowhere to be seen.
And Robert Moog and Don Buchla said, "Let there be oscillators"; and there were oscillators. There were sine waves, and triangle waves, and square waves, and sawtooth waves - the first Voltage Controlled Oscillator. But the VCO was silent, for it's waves had not yet been amplified.
Synthesis starts with oscillators. Oscillators produce a repeating signal at a particular frequency, and can be a variety of different shapes. Common oscillator shapes are sine, square, triangle, and sawtooth.
Play around with the different shapes and frequency dial and see how the produced signal changes. You can interact with the oscilloscope (the waveform display) to pause and unpause it.
Amplifiers
Soon, they gathered the frequencies together and said, "Let amplitude emerge," and thus the Voltage Controlled Amplifier was born. And from the VCA, the waves became sound and flowed forth through the air.
A signal generated by an oscillator can be fed to an amplifier. Amplifiers are circuits which take an input signal and increase its amplitude by a certain proportion, called gain. I've hooked the output of the oscillator to the amplifier, and the output of the amplifier to your browser's audio.
Be careful, but adjust the gain and see how that affects the volume of your oscillator's sound. Now, you can hear the actual waveforms!
Keyboard
more of the bible thing
You may have now noticed that we should have a better way of controlling the frequency of the oscillator and stopping the sound. To do that, we will connect a piano keyboard controller.
Attaching a keyboard let's us do two things. First, we can have the keyboard trigger the signal - in other words, only start the synth signal when the keys are being played. In analog synths, this is either done with V-trigger (having voltage be 0 until a key is pressed, at which point voltage is set high) or S-trigger (the opposite).
Secondly, the keyboard can send a control voltage (CV) to the oscillator to adjust its frequency.
Play around with the keyboard! For now, this is where the demo ends. I'll soon add filters, MIDI keyboard support, envelopes, LFOs, and more!