Are Synthesizers Considered Musical Instruments?

Along with the modern age in the twentieth century came the modern instruments to make modern music. In that vein, synthesizers were among mankind’s most epic creations, one that would change the musical landscape forever. Yet, can such a powerful device be called a musical instrument?

Are synthesizers considered musical instruments? Synthesizers are electronic musical instruments that belong to the “electrophone” category. Synthesizers generate sound using electricity to convert energy into sound and are different than the conventional, organic instruments that translate the energy of plucking, strumming, or blowing into sound.

The short answer is that every synthesizer is a musical instrument. Would you like to dive a little deeper into this complex topic and understand synthesizers’ structure and physiognomy better? Read on because that’s what’s coming up next.

What Is An Electrophone?

An electrophone, the musical instrument category synthesizers belong to, is a musical instrument that requires electronic means to generate sound. In other words, an electrophone utilizes electricity to make sounds. In the same vein, aerophones utilize a vibrating mass of air going through a specific shape to make sounds. Also, chordophones utilize the vibration of stretched strings to make a sound.

Other types of electrophone are:

  • The Theremin
  • The Ondes Martenot
  • Electronic organs (Hammond, Wurlitzer)
  • Mellotron
  • Some electronic drums (non-sample-based)

How Do Synthesizers Work?

As stated above, synthesizers transform electric current into sound. But how does it happen exactly?

Well, traditional synthesizers utilize oscillators to create sound. Still, you might be wondering what an oscillator is. It is a single-cycle waveform looped to a specific pitch usually determined by the key pressed in the keyboard (if your synthesizer is operated with one). Oscillators can be digital or voltage-controlled (VCO), depending on the synthesizer.

Let’s go a little deeper into the subject.

Addition Or Removal

Synthesizers can work with additive synthesis or subtractive synthesis. Both utilize either digital or analog oscillators in their genesis.

Additive synthesis: This is the name given to sound produced by multiple sine, square, and sawtooth wave oscillators stacked upon each other. These different frequencies add up to create what is known as “timbre”. The more oscillators involved in the creation of the sound, the more layered, complex, and unique the sound will be.

Subtractive synthesis: Subtractive synthesis is the exact opposite of additive synthesis in the sense that it removes frequencies from oscillator audio signals to create a different timbre. So, instead of building a sound up from layers of waves, this type of synthesis filters a specific layer (or several) to create a unique sound.

Understanding Filters

Speaking of which, what are filters in the synthetic music-making world? An audio filter is a frequency-dependent amplifier (or attenuator) circuit that works within (and beyond) the audio frequency range of 20 Hz to 20,000 Hz. There is a wide variety of filters that amplify/boost, attenuate/cut and/or pass defined frequency ranges/bands.

Filters shape the sound of the synth’s oscillators by carving out frequencies from the resulting audio signal.

Filters are typically low-pass, high-pass, band-pass or band-reject. Let’s distinguish each of these types:

Low-pass filter (LPF): “passes” the low-frequencies below their cutoff frequency while progressively attenuating frequencies above their cutoff. In other words, low-pass filters remove high-frequency content from an audio signal above a defined cutoff point.

High-pass filter (HPF): “passes” the high-frequencies above their cutoff frequency while progressively attenuating frequencies below the cutoff frequency. In other words, high-pass filters remove low-frequency content from an audio signal below a defined cutoff point.

Band-pass filter (BPF): “passes” a band of frequencies (a defined range above a low cutoff frequency and below a high cutoff frequency) while progressively attenuating frequencies below the low cutoff and above the high cutoff.

Band-reject filter (BRF): works by removing frequencies in a specified band within the overall frequency spectrum. It allows frequencies below the low cutoff frequency to pass along with frequencies above the high cutoff frequency.

A very well-known example that can shed some light on the concept is the wah pedal. Indeed, a wah pedal filters low frequencies when pushed with the toes and filters high frequencies when pushed with the heel (or vice versa).

The same principles apply to the filter knob on a synthesizer’s interface.

Related articles:
Audio EQ: What Is A Low-Pass Filter & How Do LPFs Work?
Audio EQ: What Is A High-Pass Filter & How Do HPFs Work?
Audio EQ: What Is A Band-Pass Filter & How Do BPFs Work?
Audio EQ: What Is A Band-Reject Filter & How Do BRFs Work?
What Are Wah-Wah Guitar Effects Pedals & How Do They Work?

Other Common Synthesizer Controls

Although oscillators and filters are a synthesizer’s main controls, some extra knobs and sliders can help tame the audio and get that specific sound you hear in your head. Let’s go through some of them so it is easier to understand how to set them to your liking.

Attack: Simply put, this knob will allow you to fine-tune the amount of time that it takes for a signal to reach its volume peak when triggered. If you are playing a synthesizer with a keyboard, it would be the amount of time elapsed since you hit the key until the sound peaks.

Decay: Decay is the opposite of attack in the sense that it’s the amount of time it takes for the signal to go from peak level to a lower, constant level known as sustain volume.

Sustain: The sustain knob modifies the volume level that the sound remains at after reaching its peak level and until the trigger (key in most cases) is released.

Release: The release control sets the amount of time that it takes for a sound to go from sustain level to silence.

Synthesizers Vs. MIDI Controllers

A very common mistake is confusing synthesizers with MIDI controllers. This is because, in most cases, they share a similar physiognomy, looks, and controls. Yet, the big difference between them is that while synthesizers are sound generators, MIDI controllers can’t create sound as a standalone unit. In this sense, a MIDI controller works as an interface to control other sound sources, like, usually, a computer. As such, it is not a musical instrument.

But is it possible to use a MIDI controller to play synthetic sounds? Well, the answer is yes, if you happen to have a synthesizer with a MIDI output and input, you can control it via a MIDI controller just as you would any sound-creation software.

Still, a MIDI controller always needs a brain to work; it can’t generate sounds on its own. Thus, it doesn’t make it to the “musical instrument” category.


Whether or not synthesizers are musical instruments is a difficult topic that can generate controversy among musicians. This is because purists do not accept the definition of electrophone as a category within musical instruments.

According to the evidence above, synthesizers are electrophones capable of synthesizing sounds to mimic other instruments or create unique sounds. And, the truth is, modern music has been and still is heavily shaped by synthesizers. Moreover, they are part of a trend that is not going anywhere but to the top of the charts.

When buying a synthesizer, it can be challenging to choose the most ideal option within your budget. For this reason, I’ve created My New Microphone’s Comprehensive Synthesizer Buyer’s Guide. Check it out for help choosing the best synth for your applications.

Choosing the right MIDI controller for your workflow and budget can be a challenging task. For this reason, I’ve created My New Microphone’s Comprehensive MIDI Controller Buyer’s Guide. Check it out for help in determining your next MIDI controller purchase.

This article has been approved in accordance with the My New Microphone Editorial Policy.


Arthur is the owner of Fox Media Tech and author of My New Microphone. He's an audio engineer by trade and works on contract in his home country of Canada. When not blogging on MNM, he's likely hiking outdoors and blogging at Hikers' Movement ( or composing music for media. Check out his Pond5 and AudioJungle accounts.

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