Musikality Net

Today we are going to talk about a topic that causes great confusion to beginning computer musicians: synthesizers and their components

When you start learning about this stuff you’ll eventually have to choose your first synthesizer, be it virtual or physical. Most of the music you’re going to write is based on a some type of synthesis, even if the instrument is not considered an actual synthesizer. Additionaly, it is a good idea to choose a synthesizer, even if you are planning to use only audio instruments. All synthesizers share some common traits which are fundamental in digital audio. By studying a synthesizer you actually get grip of what is going on with digital audio and you’ll gain knowledge that you’ll be able to transfer to other domains.

In this article, we will discuss about the basic types of synthesis. When I started learning about these things, and as I had to choose a synthesizer to start writing music, I was utterly confused. However, as my experience increased, I quickly understood that things are much simpler than it seems.

First of all, every kind of synthesis is based on an oscillator. An oscillator is anything that produces a repetitive signal, that is actually a wave.

The number of oscillators in a synthesizer can be an important factor in shaping the sound. Most synthesizers use 2 or more oscillators. The way that the oscillator produces sound depends on the type of synthesis it follows. There are many types of synthesis and we should cover them in another article, but here are some

• Subtractive Synthesis
• FM Synthesis
• Granular Synthesis
• Additive Synthesis
• Wavetable Synthesis
• Physical Modelling

Subtractive synthesis for example, which was one of the first kinds of synthesis, takes a certain waveform and subtracts harmonic content via filter, while additive synthesis adds waveforms together to create additional harmonic content.

Another component that you’ll meet in synthesizers are filters. Filters can have many forms and shapes (that will cover in another article). The purpose of every filter is to attenuate frequencies (well, actually filters can make some frequencies sound louder through resonance, but this is another subject). Filters are used to shape the sound in various way. A very common use, is to pass the signal through a low-pass or high-pass filter to give the sound a certain "frequency range". However, there are synthesizers like Native Instruments’ Massive, that uses some artistic filters, such as a scream filter, or an all-pass filter that reverses the phase of the signal.

A typical low-pass filter

Synthesizers also use to have effects. Built-in effects usually represent versions of effects you can find in many other VSTs, from various companies, like reverb and delay. However, some like Native Instruments’ Absynth, have effects with a certain artistic taste. Absynth 4 has only 4 effects, but each one is special. However, when you are choosing a synthesizer don’t get carried away with the preset sounds that are full of effects. Many VSTs for example can have in their demo versions, sounds that sound too impressive because of too much reverb. Always remember that you can add your own effects later. So, don’t choose a synthesizer based solely on effects (and demo presets ). On the other hand, some VSTs can have effects which can have their own sound, which is a good thing. Spectrasonic’s Omnisphere comes to mind and its various versions of distortion and compression.

Another very important component of synthesizers are modulation components. These are sources that are used to control other components in the synthesizer. The most common are LFOs and envelopes. LFO stands for Low Frequency Oscillator. It was once, when the circuits were still analog, an oscillator (that is a waveform) of low frequency, that was used as a modulator. Now, the oscillator doesn’t have to be of low frequency, but the basic principle is still the same. It is a waveform used to modulate components.

An ADSR envelope

Envelopes are modulators that define a certain progress of a value through time. The most common form is an ADSR envelope, which has the four basic envelope attributes: Attack, Decay, Sustain, Release. Envelopes are mostly used to control the amplitude of a note that is played. Attack defines the time it takes for the sound to reach its maximum amplitude value. Then decay determines the time it takes to reach the sustain. Sustain does not represent time, but an amplitude value. Release, determined the fade out of the note.

So for example, for piano, we’d have an attack of zero, a medium sustain and a somewhat big release time.

However, envelopes and LFOs are not the only modulation sources. Other synthesizers allow more modulator sources with various connections amon them.

So, these are the basic controls you’ll met in a synthesizer. Others might include an arpegiator, which is used excessively in trance to create arpegios, a trance gate, or other controls, like an analog knob, that adds an analog flavor to the signal.

This entry was posted on Thursday, January 8th, 2009 at 6:23 am and is filed under Tutorials. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.