Comparison

Sirens' Chor vs VAPolyMT

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Sirens' Chor

This experimental audio effect app analyzes input audio to generate a secondary harmonic voice using sine wave oscillators. The generated voice can be mixed with the original or played solo, creating a chorus effect. It's CPU intensive and operates within a specific frequency range.

Highlights
  • Harmonic analysis of input audio
  • Sine wave oscillator synthesis
  • Adjustable chorus effect
  • Second voice generation
  • AUV3 plugin support
Features
Read full description

This one is quite experimental and CPU heavy app! While working on my Chord Detector app I came up with the idea to play the found harmonics with sine wave oscillators so I can hear what the algorithm is hearing :) It turns out to be an interesting output that led me to creation of this audio effect app. What happens here is that the input is analysed for main harmonics in the range of 80Hz to 1500Hz. Then a series of sine wave oscillators are set to play those harmonics with the exact frequency and volume and their output is added to create a second voice. This second voice can then be mixed with the input to create some kind of chorus or played alone. All this is CPU heavy process so it should be used with care... Also to make this effect possible I had to use limited range 80Hz to 1500Hz so it is not suitable for every instrument and you have to keep that range in mind when producing. Some very fast volume and frequency changes are applied to the oscillators. The app is AUV3

About

VAPolyMT

This powerful synthesizer app offers bi-timbral polyphony with analog-style sequencers and assignable macro controls. It functions as a standalone application or an AudioUnit Extension, supporting MIDI, Ableton Link, and audio export. Project files are savable via iCloud Drive for cross-platform access.

Highlights
  • Bi-timbral polyphonic synthesizer
  • Analog-style step sequencer per timbre
  • Assignable macro controls
  • AudioUnit Extension (AUv3) support
  • Ableton Link and MIDI support
  • iCloud Drive project sharing
  • Built-in effects and piano roll editor
Features
Read full description

VAPolyMT is a bi-timbral polyphonic synthesizer for iPhone, iPad and Mac. It features analog style step sequencer per timbre and assignable macro controls. It operates as a stand alone or as an AudioUnit Extension (AUv3). Stand Alone supports Ableton Link, MIDI and audio file export. Each synthesizer consists of two oscillators, mixer, resonant low pass filter, resonant hight pass filter and amplifier. The synthesizers can be layered or can be split. Built-in Effects include delay, chorus, flanger, reverb, eq and compressor. VAPolyMT also includes sequencer which features piano roll editor and parameter automation. Project files can be saved in iCloud Drive, so that the project can be accessed from iPhone, iPad or Mac. Main Features Bi-timbral polyphonic subtractive synthesizer. Analog Style Step Sequencer per timbre. Eight Assignable Controllers. Maximum 8 voice polyphony. it depends on performance of the device it is running. Built-in effects and piano roll sequencer. Support Audio Unit Extension (AUv3). Support MIDI 2.0. Support Foot Pedal and Per Note Control. Works on iPhone, iPad and Mac. Support iCloud Drive to share project files between the platforms. Audio Export. Linear PCM format (AIFF, WAV and CAF) and compressed format (AAC) Support Ableton Link, Bluetooth MIDI, MIDI In / Out. Include more than 200 Factory Presets. Improvements Support MIDI Foot Pedal (CC#11, CC#64) Support MIDI2.0 Per Note Control Messages MIDI CC Settings are saved. It will be recovered when the app launched in the next time. System Requirements iOS 17.0 or later macOS 14.0 or later Devices with Apple Silicon are recommended. A13 Fusion or above is highly recommended. if sound is distorted when using a device with less CPU power, reduce number of voices. AudioUnit Extension (AUv3) requires host application which support AudioUnit Extension. AudioUnit Extension is supported by Apple Logic and Apple Garage Band on iOS and macOS. For any other DAW, it depends on the application and some of them don’t support AudioUnit Extension.

Screenshots

Sirens' Chor3 screens
VAPolyMT4 screens

Verdict

The call

The clearest difference is price: Sirens' Chor at $3.99 against VAPolyMT's $14.99. Sirens' Chor also leads on iOS requirement (10.0 vs 16.6). VAPolyMT's advantage is rating (5.0 vs 4.0) and update cadence (every 11 months vs every 39 months). On ratings volume, ads, in-app purchases and monetization model there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Sirens' Chor costs $3.99 and VAPolyMT $14.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

VAPolyMT holds the better App Store score, 5.0 against 4.0. Both are backed by a comparable volume of ratings — 2 and 4 respectively.

UpkeepUpdate frequency

Sirens' Chor ships an update every 39 months, VAPolyMT every 11 months. Both last shipped on October 24, 2026.

Scorecard4 real differences · 6 level
Sirens' Chor versus VAPolyMT: the parameters behind the verdict, then further details
ParameterSirens' ChorVAPolyMT
Price$3.99 — better$14.99
Rating4.0 (2 ratings)5.0 (4 ratings) — better
Positive reviews100.0% of reviews—
Number of ratings24 — better
Update frequencyEvery 39 monthsEvery 11 months — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
DevicesiPhone, iPad, iPodiPhone, iPad, Mac
Requires iOS10.0 — better16.6
Further details — not scored
Size11 MB18 MB
Age rating4+4+
DeveloperAleksandar MlazevRyo Togawa

Customer experience

Sirens' Chor

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews3 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

VAPolyMT

All ratings4 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Sirens' Chor

No in-app purchases

None

VAPolyMT

No in-app purchases

Questions

Is Sirens' Chor free?
Sirens' Chor costs $3.99, with no in-app purchases.
Is VAPolyMT free?
VAPolyMT costs $14.99, with no in-app purchases.
Which has better reviews, Sirens' Chor or VAPolyMT?
VAPolyMT is rated higher. Sirens' Chor averages 4.0 out of 5 from 2 ratings, while VAPolyMT averages 5.0 from 4 ratings.
Do Sirens' Chor or VAPolyMT have ads?
Neither Sirens' Chor nor VAPolyMT shows ads.
Which is updated more often, Sirens' Chor or VAPolyMT?
Sirens' Chor ships an update every 39 months, and VAPolyMT every 11 months. Most recently, Sirens' Chor was updated on October 24, 2026 and VAPolyMT on October 24, 2026.

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