Ultimate Synthesizers Guide

Imagining life without music is rather difficult because of the way we have come to depend on it like a drug. If music is your thing, therefore, then you probably know what a synthesizer is. However, if you don’t, worry not, you have come to the right place.

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So, what is a synthesizer?

A synthesizer, popularly known as a synth is an electronic device that falls under the category of a musical instrument. Its purpose is to generate audio signals that can be converted to sound. This instrument can imitate traditional musical instruments like the piano, the flute, even the vocal sounds as well as natural sounds that can be derived from the ocean waves. A synthesizer can also be used to generate novel electronic resonances. Like other musical instruments, synthesizers are played.

How are synthesizers played?

Synthesizers are mostly played using other musical instruments like a musical keyboard. However, they can also be controlled using other devices the likes of a music sequencer, instrument controller, guitar synthesizer, a wind controller, or a fingerboard.

There are synthesizers that have built-in controllers and those that do not. Those that do not have built-in controllers are known as sound modules. They are controlled using USB, MID or at times using CV/gate which would require you to use a controller device that is often in the form of a MIDI keyboard or any other form of a controller.

To generate sound, synthesizers use various methods. Such methods include physical modeling synthesis, sample-based synthesis, phase distortion synthesis, wavetable synthesis, subtractive synthesis, frequency modulation synthesis, and additive synthesis.

Methods of sound synthesis

  • Subtractive synthesis technique

This is a method of sound synthesis whereby parts of the audio signals that are rich in harmonics are attenuated to alter the sound’s timbre using a filter. This technique can be applied in any form of an audio signal. However, the sound that is most commonly associated with this technique of synthesis is similar to that produced by analog synthesizers that were used back in the 1960s and the 1970s. In the analog synthesizers, the harmonics of simple waveforms like the sawtooth, the pulse or the square waves are tempered with a resonant low-pass filter that is controlled by voltage. 

Synthesizers that use subtractive synthesis include virtual analog, digital, and software synthesizers. These synthesizers, at times, use this technique in collaboration with other techniques of sound synthesis.

  • Additive Synthesis technique

This is a sound synthesis technique that adds shine waves together to create timbre. Timbre, in regards to musical instruments, can be defined to consist of inharmonic partials or overtones or several harmonics. Each harmonic is a sine wave made up of different amplitude and frequency that with time, decays and swells as a result of modulation that is derived from an ADSR envelope or a low-frequency oscillator.

The sound developed by additive synthesis technique is derived from adding the output of several sine wave generators. If there ever is a need to make alternative alterations, implementations can be pre-computed in the wavetables or the inverse fast Fourier transform.

  • Wavetable synthesis technique

It is a method of sound synthesis that is used to create periodic forms of waves. It was developed in the early 1970s and published later in 1979 by Palm Product GmbH’s Wolfgang Palm. It is often used in the production of musical tones. From the time that it was produced, this technique has been adopted as the primary form of sound synthesis in synthesizers that were built by the Waldorf Music and PPG. For Ensoniq and Access, it has been used as a secondary or auxiliary sound synthesizing technique.

Currently, this mode of sound synthesizing is used in synthesizers that are software based for computers and tablets. It is also used in applications, especially those that are offered by Waldorf and or PPG among other brands.

  • Frequency modulation synthesis technique

Known to many as FM synthesis, this is a model where the frequency of a single waveform, usually known as a carrier is altered depending on the amplitude of the signal of modulation. This model can be used in the creation of both harmonic and inharmonic sounds. In the synthesis of harmonic sounds, the signal of modulation mush has a harmonic relationship with the carrier signal, which happens to be the original signal. The continued increase in the amount of frequency modulation leads to the development of a complex sound that gets more progressive with the increase of FM. Inharmonic signals, on the other hand, are created using modulators that have frequencies that are not integral multiples of the initial carrier signal.

This technique may be challenging when used in analog oscillators as it may result in the production of unstable pitches. They can, however, be implemented digitally.

  • Phase distortion synthesis

This mode of sound synthesis was established in 1984 by one Casio. It is similar to the phase modulation synthesis method in that both these models change the harmonic content of the carrier waveform in a mostly dynamic way by using another modulator in the domain time. Despite these similarities, the result of these two applications results in sounds that are very different from each other.

  • The physical modeling synthesis technique

This is a sound synthesis model in which the waveform of the sound that is intended to be generated is computed with the use of a mathematical model. This means that a set of equations and algorithms are used with the aim of stimulating a physical sound source that is usually a musical instrument.

  • Sample-based synthesis technique

It is a mode of audio synthesis that works in contrast to additive synthesis and subtractive synthesis. The main difference with this sample-based synthesis is the fact that the seed waveforms are sounds that are sampled or rather, instruments rather than the fundamental waveforms the likes of sine and saw waves that are used in other modes of synthesis.

Understanding the process through which a synthesizer works

An oscillator

This is the way that a synthesizer creates a basic sound. The oscillator is also known as a tone generator. It gives out a pulsing electrical signal that creates a waveform. The number of times the pulses go to positive and negative, and returns (frequency) is what is used to determine the pitch of the sound. An oscillator can be set to come up with a basic waveform which helps to imitate the timbres.

A filter

Filter is used to varying the basic waveforms to a certain extent. It is a form of an electric circuit that works by choosing increasing or decreasing frequencies of a specific region and smoothing the edges of the initial waveform. Once you apply a filter to a waveform, you can remove some overtones making the waveform appear more rounded. The waveform becomes more rounded with the continued removal of overtones. The final product is a sine-wave.

A sine-wave is referred to as the simplest waveform that occurs naturally and does not have even the slightest overtone. It is free from any form of edge — kind of like the sound that is made by a flute.  

The amplifier

This one is used to control the volume of the sound produced in the synthesizer. When the sound created is passed through the amplifier circuit, the volume is controlled. It can raise or lower the height of a waveform, which results in alterations in the volume of the waveform. What happens is that the user can create a waveform by simply pressing a key on the oscillator, the waveform is then passed through the filter, and finally, it is then amplified using the amplifier.

The envelope

Natural sounds cannot be switched on and off. These sounds are also not static as they keep changing their character as time passes. A real-life sound comes with a fade in and a fade out period. Several sounds can change their pitch from the onset to the fade out. This is called the envelope of the sound. By controlling each synthesizer circuit’s envelope, we can simulate the effects. The oscillator envelope controls the way the pitch transforms through the duration of the sound. The envelope of the amplifier, on the other hand, controls the changes that the sound undergoes through the period of the time. The filter also has its envelope. This envelope is used to manage the changes that the dullness or the brilliance of the sound goes through.

Synthesizer envelopes have four stages that control four different parts of the envelope. These are:

  • The attack, which is the onset of the sound
  • The decay, which is the first fading of the sound
  • The sustain, which is the point where the sound is held the longest as the key is pressed
  • And the release, which is the fade out of the sound.

The low-frequency oscillator

Almost all synthesizers come with a wheel controller that is placed to the left of the keyboard. It is often labeled as the modulator. Its work is to allow for the performer to be able to mix in an extremely slow oscillation to a sound that creates a vibrato or a filter sweep effect.

The voices

Having gone through the above processes, we now have a synthesizer voice that is usable. However, this is a single voice that cannot be played using cords yet. Initially, with the monophonic synthesizers, you could not play more than one chord. Therefore, you needed more than one synthesizer for different chords. The addition of more oscillators, amplifiers, and filters to a single oscillator made it possible to play more than one sound at a go. There are those synthesizers that can play between 2, 32, 64, and a hundred and twenty-eight voices at the same time.

Waveforms and samples

Hybrid synthesizers often come with banks of samples of audios known as waveforms. These are digital sound clips that can be used in the place of simple tones of the oscillator. The modules of the synthesizer include the filters, envelopes, LFOs, and others. They can be applied to create a myriad of sounds. Natural sounds can also be recorded using samplers and an attached microphone. Such sounds can later be converted and used in the form of waveforms. It is also possible to create complex sounds by combining wave samples and the voices in the oscillator.

The origin of sound synthesizers

A man by the name Moog is referred to as the first designer of the synthesizer. His first design was called the Moog Modular Synthesizer, and it was developed between 1963 and 1964. Beginning in the late 1960s, miniaturized solid-state components of a synthesizer were developed by one Harald Bode. With this development, the synthesizer became a self-contained and portable instrument. By the beginning of the 1980s, companies had begun dealing synthesizers that were both compact and modestly priced. It wasn’t long before digital synthesizers and samples were developed and sold to the public.

With the development of (MIDI), integrating and synchronizing synthesizers with other electronic instruments was made possible. This led to a revolution in the mode of music composition, allowing room for creativity and innovation in regards to composition.

Synthesizers Conclusion

It is impossible to create and manipulate sounds the way a synthesizer does physically hence the importance of synthesizers in composing music. Synthesizers are commonly used in the composition of electronic music, synth pop music and most significantly in electronic dance music popularly known as EDM. Synthesizers can be used in the studios as well as during live performances and events. Learning how to use a synthesizer is not as technical as advertised. However, it takes skills, passion, and prowess. Regardless, learning how to use a synthesizer can go a long way in helping a musician be able to create music in an innovative and creative manner. When it comes to a keyboard synthesizer, it may look like a piano in several ways; however, as explained above, it works entirely different as compared to a piano.

Seriously, what would we do if these legends had not developed synthesizers and revolutionized music for good!

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