Synthesis

For this week's assignment in the Introduction to Music Production class on Coursera, I'm going to demonstrate the usage of various controls on a synthesizer.  I will be using the Analog synthesizer in Ableton Live.

First is the oscillator - this is the part of the synthesizer that generates the sound.  The oscillator generates sound by producing one of four waveforms: sine, sawtooth, square, or white noise.  In the following video, I demonstrate the first three waveforms (I will use the white noise setting in the next section).  Then, I show how the frequency of the waveform can be modified at three different levels of granularity by turning the Octave, Semitone, and Detune knobs:

Next is the filter - this component shapes the sound coming out of the oscillator.  The four most common filter types are:

• Low-pass: filters out sound above a given frequency
• Band-pass: filters out sound above and below a given band of frequencies
• Notch: filters out sound at a given frequency
• High-pass: filters out sound below a given frequency

In the following video, I play some white noise and filter it using one of these filters at a time.  After selecting each filter type, I sweep the filter frequency to demonstrate the filter's effect.  Then, I demonstrate the resonance control, which uses feedback to add a peak in the spectrum at the filter's frequency:

Finally, we have the amplifier - this component modulates the amplitude of the sound.  The amplifier applies an envelope to the sound that has four attributes:

• Attack Time: the amount of time it takes for the sound to reach its peak amplitude after a note is played
• Decay Time: the amount of time it takes for the sound to reach its sustain level after the attack phase
• Sustain Level: the level at which the amplitude will remain from the end of the decay phase to the release of the note
• Release Time: the amount of time it takes for the amplitude to reach zero after a note is released

In the following video, I start by increasing the attack time in order to make the sound fade in slowly when a note is played.  Then, I decrease the sustain level to make the sound more percussive, and I demonstrate how the decay time affects the transition from attack to sustain.  Finally, I play around with the release time, initially making the sound end abruptly when a note is released, and then making the sound fade out slowly when a note is released:

Thanks for watching!