We all know that synthesizers allow us to make beautiful music. There are so many options available, right from beginner to advanced levels. They also come in at varying price points and brands. So, even with a tight budget, you can own one. However, have you ever asked yourself the question, how does a synth work? If yes, we will explain it to you in detail.
What Is A Synth?
The human ear captures and converts vibrations into sound. A synth uses the same process, only that it converts electrical signals into sound. You can speed up, slow down, or modify the sound in any way you wish.
The synth is an electronic keyboard, which you can use to generate any type of sound. You can also copy and mimic different sounds from different instruments. You could, for example, recreate piano or violin music easily. The whole basis of a synthesizer is to put together different pieces to generate something new.
You have the option of software or hardware when choosing a synthesizer. The latter are physical objects, which you can hold in your hands. Software or digital synthesizers are those you upload or link with a computer to get to their functionalities. They incorporate the use of pre-programmed algorithms and processors to create sound waves.
Understanding How a Synth Works
The best way to comprehend how a synth works are to understand each part’s critical role.
- Keyboard, which produces the actual note
- Knobs, buttons, and sliders for the perfect tone quality
- MIDI control allows for more dynamic sound by linking samplers, sequencers, digital workstations, and other software and devices
Other Parts You Need To Know
1. The Oscillators
Think about the oscillators, much like you would, building blocks if you were constructing a house. They produce sound through the creation of steady pitches at a given frequency through the shaping of voltage.
Depending on the synthesizer you buy, you can find 1, 2, or 3 oscillators. You can create unique sounds depending on the voltage or wave.
The oscillator works with different waveforms, namely the fundamental and harmonic frequencies. The perfect combination or balance of the waveforms is what creates that unique sound.
The waveforms or oscillation patterns are:
- A sine wave has no harmonics, is the purest and the basis for all the other waves
- The square wave has harmonics and contributes to the square shape
- Sawtooth wave contains the most harmonic content
- Triangle shares similarities with the square but with less powerful harmonics
The synth controls the shape, speed, structure, or size of a waveform to create the sound you desire. It could be a timbre, pitch, or tone, which goes through the speaker as an electrical signal to our ears.
2. Frequency
You may have heard people refer to frequency, and wonder what it means. Frequency is the speed at which a waveform will complete a cycle. The higher the pitch, the faster the frequency. The pitch will also go into octave if you double the frequency.
In musical terms, Note A is 440 Hz. Double the frequency, and you have note A on a higher octave. For a human ear to hear the sound, you can only go as low as 20 Hz.
3. The Filters (VCF)
The filter receives a signal from the oscillator. The VCF works much like a dust filter, which removes dust from the atmosphere. In the case of a synth, the filter has the task of removing frequencies from sound, while letting others pass through. You get a unique sound by emphasizing the frequency you select.
- Low pass and high pass filters both have cut off points. Only those frequencies below or above can pass through, respectively. You get warm or crispy sounds depending on the filter type. If, for example, you find that some of the sounds from your synth are very high, sharp or shrill, you can correct it with the low pass filter. The same applies in the case of high pass filters. If you feel that the bass is too heavy, the high pass filter will eliminate the low frequencies.
- Bandpass filters create nasal sounds. They work with frequency groups and can emulate voice frequencies.
- Notch filters give creative flexibility, and you use them to remove any frequency you do not want.
4. Amplifiers
Amplifiers boost or control volume. The envelope generator shapes sound along with different parameters or contours.
The parameters are decay, release, attack, or sustain.
- Attack refers to the time from when you press the keyboard, to when it reaches full volume.
- Sustain is the volume you get when you press the key.
- Decay is the length of time the maximum volume falls, to the level set by the sustain.
- The release is how long it takes for the volume to go back to zero when you release the key.
5. Modulation
Synthesizers come with different modulations that help determine the sonic property. Modulation implies movement or change within the synth.
- LFO or low-frequency oscillator work at very low frequencies. So low, in fact, that the human ear is not capable of picking up that sound. It basically has the role of modulating other sounds to achieve different effects. You can achieve vibrato on the oscillator, tremolo on amplitude, and wobble bass when you apply it to the filter.
- Ring modulators create new frequencies through the combination of two signal inputs.
- Subtractive synthesis filters out frequencies to achieve a new sound
Depending on the synth you buy, you can multiply or add different waves to achieve different sounds.
Final Thoughts
We have tried to answer the frequently asked question, How does a synth work? Synths provide flexibility with the type of sounds they can produce. It pays to have a basic understanding of how they work, and that’s what we have covered above.
The best way to learn is to experiment with different sounds. If you are a beginner, ask for help to understand some of the basic concepts. You will also find a lot of tutorials online that can help you learn how to use a synth.