What Is A Synthesizer Voice?


Synthesizers are among the most unique instruments in the world, with so many differences between one synth and the next. The number of voices a synthesizer has is one of the many differentiators in its performance and sound.

What is a synthesizer voice? A synth voice is a single audio path responsible for producing a single note. Each voice has its own independent audio path, complete with oscillator(s), filter(s), modulation(s), effect(s), amplifier(s), etc. Monophonic synths have one voice, and polyphonic synths have multiple voices.

In this article, we’ll discuss synthesizer voice in greater detail and consider a few real-world options of synths with a variety of different voice counts.


What Is A Synthesizer Voice?

A synthesizer voice is a single path of audio within a synth. A signal path starts with an oscillator (or multiple oscillators), goes through filters, effects and amplifiers, and finally reaches the output.

Generally speaking, the number of voices equals the number of notes a synth can play at once. So then, monophonic synthesizers have one voice since they can only produce one note at a time.

The Korg Monologue (link to check the price on Amazon) is a monophonic synth with one voice, though it has two oscillators and 25 keys.

Korg Monologue

Korg is featured in the following My New Microphone articles:
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A 16-voice polyphonic synthesizer, for example, will be capable of playing 16 simultaneous notes.

The Moog One (link to check the price at Sweetwater) comes in a 16-voice version whereby each of the 16 voices has three state-of-the-art analog VCOs, two independent analog filters (series or parallel), a dual-source variable analog noise generator, an analog mixer with external audio input, four LFOs, and three envelope generators.

Moog One

Moog is featured in the following My New Microphone articles:
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The best, most graphic comparison, perhaps, is a human choir. If you have only one singer, you can work with a single voice at a time. This singer needs to have all the elements to produce sounds such as vocal cords, lungs, mouth, tongue, etc. (analogous to the synthesizer signal path).

If we have, let’s say, an eight-person choir, then we have eight voices. With these voices, we can create, for example, a chord. This is because each of the singers has got all the elements to produce the needed sound.

Synthesizer voices work the same way; each available voice will have an oscillator (vocal cords), filters (mouth, tongue), and an amplification stage (lungs, diaphragm). If your synth has a single voice, you can only press a key at a time to create sounds. On the other hand, if you have multiple voices, you can add different notes to the mix.

By that token, a 6-string guitar has 6 voices, a grand piano has 88 voices, and a saxophone has 1 voice.


Synthesizer Voices & Polyphonic Synths

Polyphonic synthesizers have voices that can be played in unison to create multiple layers of harmony and chords. In this sense, the more available voices you have, the more complex the chord and resulting sound can be.

For example, an 8-voice synth can create chords that have a maximum of eight notes. Attempting chords with more than 8 notes will result in “note stealing”. This means that the moment you hit the ninth note, one of the eight ones you were pressing down will stop sounding. The “stolen” note could be the least recent note, the highest note, the lowest note, or some other defined note.

If we go back to the choir example, if you need a ninth note and only have eight singers, you need a singer to stop singing one note to sing a different one. No singer can sing two notes at the same time, nor can a synth voice.

It is the same scenario with polyphonic synths. If you have more keys held down than available voices, the extra notes will steal notes that were sounding before.


Beware Of Note Decay

One thing to keep in mind is note decay, which could more appropriately be called note release (in terms of envelopes).

A note in the state of decay is still playing through the synth’s engine. What does this mean? Well, it means that you can’t play another note unless you have a free voice to do it. Thus, if your sounds have a long release time (the time it takes for the sound to die out after a key is released completely), and you need to play another one abruptly after that, you’ll be stealing the note from the decaying sound.

In this sense, those who utilize synthesizers to play, for example, ambient music or complicated landscapes that require long tails in each note need a higher number of voices since some of them will be occupied for longer while the tails decay.


How Many Synth Voices Do I Need?

This is the natural next question after understanding what a voice is and what it does. This is not a question with a generic answer; it is mostly something that needs to be answered with the specifics of each case.

Let’s take a look at a few common scenarios to help us understand how many synth voices we need:

Piano and organ-like sounds: these synth patches tend to resemble the real instrument. In the case of a piano, it is an instrument with 88 voices (one per key). These instruments are often played with fast attack and decay. Therefore, the number of voices can be close to what our fingers can do (10). However, these instruments are also capable of more sustained playing, so perhaps a voice count well above 10 is appropriate for greater realism.

Atmospheric, trip-hop, and long-decay sounds: those who want to create more complex sonic pictures with their instrument will need a larger number of voices. For example, the “stacked mode” available in many synthesizer models uses two voices per note. Thus, to play 8 notes, you need 16 voices. In this regard, perhaps a digital synthesizer capable of producing 128 different voices simultaneously is the best option, like those from the Yamaha MODX Series (link to check the price at Sweetwater).

Lead and bass sounds: some single-note synthesizers (such as the aforementioned Korg Monologue) can work wonders to play the low register of a song, create a cool groove, or be the melody on top of a work progression. This is because being constricted to a single note at a time makes room for different ways of playing. Moreover, they are easier to integrate into a mix and tend to have a better, more defined sound since manufacturers only need to focus on one voice.

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Conclusion

Understanding synthesizer voices is paramount to trace your path in the synthesizer world with the gear that best suits your creativity. Furthermore, as you become more familiar with concepts and sounds in the synthetic realm, you’ll be able to narrow down your search and also experiment with new sounds to move the sonic barriers of your music further away.

In today’s music, technology plays a huge role. Moreover, it is becoming more complex and powerful every day. Following the advice above, you’ll have a better understanding of how many voices you need to have your own musical voice heard!


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.


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

Arthur

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 (hikersmovement.com) or composing music for media. Check out his Pond5 and AudioJungle accounts.

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