Antares Harmony Engine harmony plug-in: features and spec-based rating

Antares’ Harmony Engine is a plug-in that makes up to four-voice harmonies from a single vocal in real time. You can make harmonies in three ways: specifying notes one by one, playing them on a MIDI keyboard, or choosing a chord and leaving the rest to it, and tone, vibrato, pan and octave can be changed for each voice.

A harmony and doubling plug-in makes harmonies from a single vocal, or gives it the thickness of several people singing.

In this article we compare Harmony Engine with 10 harmony and doubling plug-ins and rate how well it serves its purpose on three criteria. The basis is official manufacturer information.

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Image: from the Antares official website (product image)

Summary

Among the 10 harmony and doubling plug-ins, Harmony Engine is rank S. The ranks run S, A, B and C, and S is the top. Averaging the scores for the three criteria (out of 5) gives 5.0.

Strengths

• Range of effects (5 points): it can make a wide range of effects, such as harmonies, voice layering and width.
• Speed (5 points): you can get an effect quickly just by choosing, or from automatic creation.
• Per-voice adjustment (5 points): you can adjust each created voice in detail to finish naturally.

Who it suits: people who want to build harmony parts for a vocal by themselves.

Main features of Harmony Engine

Up to four-voice harmony from one voice

A harmony and doubling plug-in is a tool that makes voices at other pitches (harmonies) or same-pitch layers (doubling) from one voice. Harmony Engine makes up to four-voice harmonies on the spot from a single vocal or a single-note instrument. For each of the four voices you can change tone, vibrato, pan and octave.

Just choose a chord and leave it to the plug-in

You can have it make the harmonies just by choosing a chord, decide them by playing a MIDI keyboard, or build them one note at a time yourself. It also works together with AutoKey 2 and AutoKey Mobile, which detect the key. There is also an adjustment that adds human-like wobble.

Built-in Choir turns them into a chorus

With the built-in Choir technology, each of the four harmonies can be multiplied into 2, 4, 8 or 16 voices. Tone, vibrato and left-right spread can also be adjusted for each voice.

Video: “Tutorial: Introduction to AVOX Harmony Engine with Josh Carney” (official AutoTune YouTube channel; narration in English) Watch on YouTube

Where it is useful

• Adding harmony that follows the chord to the chorus of a song
• Making a four-part chorus from a single vocal
• Using Choir to give a harmony the thickness of a choir

Rating by criterion

Range of effects: 5 / 5

We check how many of harmonies, same-pitch voice layering (doubling), choir and stereo width it can make.

Besides up to four-voice harmony, the built-in Choir can multiply each harmony to 2 to 16 voices, and stereo width can also be adjusted (official page).

Speed: 5 / 5

We check whether you can get an effect quickly, for example by choosing or automatic creation.

You can leave harmony to the plug-in just by choosing a chord, and it works with AutoKey, which detects the key. You can also build notes one by one with MIDI or by hand.

Per-voice adjustment: 5 / 5

We check whether you can make the created voices sound natural (for example by shifting the timing or tone of each voice).

Tone, vibrato, pan and octave can be changed for each voice, and there is an adjustment for adding a human feel.

How we score (Harmony and doubling plug-ins)

Criterion	Basis	5 pt	4 pt	3 pt	2 pt	1 pt
Range of effects	Which of harmonies, same-pitch voice layering (doubling or choir) and stereo width are officially described	All three	—	Two of the three	One of the three	—
Speed	How quickly you can get an effect (automatic creation, just choosing, presets)	Parts can be created automatically (harmonies that follow the key or chord, or doubling from the original voice)	The effect is decided just by choosing the number or type of voices	Choose from presets	Detailed settings are needed	—
Per-voice adjustment	Features that make the created voices sound natural	Tone, vibrato, pan and more can be changed for each voice	Variation between voices, or per-voice volume and pan, can be adjusted	The tone and wobble of the whole effect can be adjusted	Volume and pan only	—

Each criterion is scored from 1 to 5 on how well the product serves one goal: adding harmonies, thickness and width to a vocal. Scores follow the conditions in the table above. So that products that make harmonies and products that double (layer the same pitch) can be compared by the same standard, there are three criteria: "Range of effects", "Speed" and "Per-voice adjustment". The basis is official manufacturer information. The naturalness of the sound has not been compared by ear, so it is not part of the score. Price is not part of the score. Features that cannot be confirmed from the manufacturer's or a retailer's description are scored as if absent. The "OBS (streaming)" column in the table shows whether the official page lists the VST2 format that the streaming software OBS Studio can use (○). OBS does not support the VST3 format. It is not part of the score.

Harmony Engine screens and images

Image: from the Antares official website (product image)

Harmony Engine system requirements and getting started

Operating system	Windows 10 and 11 / Mac (macOS 14 or later)
Plug-in formats	VST3, AU, AAX
Other	Available as a one-time purchase and also included in Auto-Tune Unlimited (a subscription)
Trial	Free to try (official site)
OBS (streaming)	Does not work as it is (VST3 only). It can be loaded through a bridge plug-in

Checked on the manufacturer’s official pages on September 27, 2026.

Compared with other harmony and doubling plug-ins

Click a heading to sort. On a phone, the table scrolls sideways.

Read next

• Choir: features and rating (rank A)
• Duo: features and rating (rank A)
• Quadravox: features and rating (rank B)
• MicroPitch: features and rating (rank B)