Sirens' Chor vs VAPolyMT
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
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.
- Harmonic analysis of input audio
- Sine wave oscillator synthesis
- Adjustable chorus effect
- Second voice generation
- AUV3 plugin support
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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
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.
- 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
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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
Verdict
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
Sirens' Chor costs $3.99 and VAPolyMT $14.99 up front. Neither carries in-app purchases, so what you see is what you pay.
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.
Sirens' Chor ships an update every 39 months, VAPolyMT every 11 months. Both last shipped on October 24, 2026.
| Parameter | Sirens' Chor | VAPolyMT |
|---|---|---|
| Price | $3.99 — better | $14.99 |
| Rating | 4.0 (2 ratings) | 5.0 (4 ratings) — better |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 2 | 4 — better |
| Update frequency | Every 39 months | Every 11 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Mac |
| Requires iOS | 10.0 — better | 16.6 |
| Further details — not scored | ||
| Size | 11 MB | 18 MB |
| Age rating | 4+ | 4+ |
| Developer | Aleksandar Mlazev | Ryo Togawa |
Customer experience
Sirens' Chor
VAPolyMT
In-app purchases
Sirens' Chor
No in-app purchases
VAPolyMT
No in-app purchases
Questions
Is Sirens' Chor free?
Is VAPolyMT free?
Which has better reviews, Sirens' Chor or VAPolyMT?
Do Sirens' Chor or VAPolyMT have ads?
Which is updated more often, Sirens' Chor or VAPolyMT?
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