I’m Gabriel Marcondes, a computer engineer from Cachoeira Paulista, Brazil, and I play the electric guitar as my hobby. Following my crescent interest in music composition and production, I enrolled in Berklee’s Introduction to Music Production, via Coursera‘s MOOC platform, and I’m writing this as the sixth and final assignment.
This week’s main topic is Synthesizers, and this text is about the main modules: Oscillator, Filter, Amplifier, Envelope, and LFO.
The Voltage Controlled Oscillator, or Oscillator for short, is the the part of a synthesizer that generates the waveform for the sound. Choosing between different waveforms gives us different kinds of sound. Sine, sawtooth, square and triangle waves are the most used, but you can make sounds with virtually any kind of wave.
The Voltage Controlled Filter, or simply The Filter, is the part that shapes the spectrum of the sound. Usually it is a low-pass, very important to cut high-end and avoid excessively bright timbres; but other filters are also useful (band-pass, high-pass, notch and comb filters). Its main parameters are:
- cut-off frequency
- resonance, an amplification that gives emphasis on the cut-off frequency.
The Voltage Controlled Amplifier, or simply Amplifier, is the gain stage for the signal, generated by the oscillator and filtered by the filter. We control the amplification with an Envelope.
The Envelope is a kind of automatization of the volume control, applied at every note-on event, when the synth receives that event and then creates the signal. The parameters are:
- Attack Time, the time it takes from the note-on event until reach “full volume”
- Decay Time, the time it takes to go from full volume to the sustain level
- Sustain Level, the volume level for the note, until the note is released
- Release Time, the time it takes to go from sustain level to zero, after the key is released (note-off event)
The Low Frequency Oscillator is a secondary modulation that can be used to control other modules. It is configured with a low frequency, usually lower than the human ear range (below 20Hz), and we don’t hear the LFO itself; instead, we hear its effect on other modules, using it to control other parameters, for example the pitch of the oscillator waveform, or the cut-off frequency of the filter. It also has the parameter Amount, that defines how much the LFO wave will impact the other modules.
So these are the main points in this topic. Of course it is a lot more complicated in practice, I wanted to create a demonstration with some music of mine, but I had no time for that.
Thanks for reading. It was a really good course, what do you think?
Hope to have you reading me again in the future!
I usually write in portuguese here, some tales and chronicles about computers, music and trips. If you can read portuguese, go ahead and look at some of my texts, hope you enjoy!
Aos meus leitores brasileiros perguntando “que é isso???”, é um texto como lição de casa de um curso on-line que estou fazendo. Este foi o último.