microTERA vs Sirens' Chor
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
microTERA
Explore unique sonic textures with this waveshaping synthesizer. Generate novel sound patches randomly or program them with detailed controls. Includes a variety of built-in effects and advanced sequencing capabilities.
- Waveshaper with user programmable shape
- Random sound patch generation
- Sequencer with programmable steps
- Built-in effects (Chorus, Phaser, Reverb, etc.)
- Over 150 factory sounds
- Audiobus and Ableton Link compatible
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Waveshaping Synthesis is a type of distortion synthesis that can create dynamic spectra in a controlled way. In waveshaping, it is possible to change the spectrum with the amplitude of the sound. A simple example of this method is the clipping caused by overdriving an audio amplifier. These simple method creates an astonishing variety of sounds which are very unique and can't be reproduced by any other contemporary synth! microTERA gives you also a method of getting randomly generated sound patches in a way you never experienced before: roll the dice! Every single try gives you a new unique sound patch, really every try, promised… Waveshaping Synthesis • Wavehaper with user programmable shape • Spectral shape specification • Three sine oscillators • Feedback input for noise components • 4 Low frequency oscillators • 4 Envelopes with tempo sync • 64 time/level segments per envelope • Monophonic or polyphonic with 16 voices. • Over 150 factory sounds • Uses programmable sequences with up to 32 steps. • Can trigger single notes and chords. • Unique randomizer generates Arpeggios with 100% usability. • 32 Arpeggios included, unlimited useer arpeggios possible. • For each step you can program tie, accent, transposition and note order Effects • Chorus • Phaser • Distortion (Tape/Tube/...) • Echo/Delay • Reverb Global • Audiobus compatible (Input slot) with state saving • Support for Ableton Link. • Inter App Audio compatible. • CoreMIDI / Virtual MIDI • Audio recorder with Metronome. • Upload to SoundCloud and File Export. • Audio pasteboard.
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
Screenshots
Verdict
The clearest difference is rating: microTERA at 4.9 against Sirens' Chor's 4.0. microTERA also leads on update cadence (every 4 months vs every 39 months) and price ($1.99 vs $3.99). Sirens' Chor's advantage is review sentiment (100% vs 81%) and device support (3 vs 1). On ads, in-app purchases, monetization model and iOS requirement 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
microTERA costs $1.99 and Sirens' Chor $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.
microTERA holds the better App Store score, 4.9 against 4.0. Both are backed by a comparable volume of ratings — 9 and 2 respectively. Written reviews complicate that: 81% of microTERA's written reviews are positive against 100% of Sirens' Chor's, so the app with the better star average is not the one people write more warmly about.
microTERA ships an update every 4 months, Sirens' Chor every 39 months. The most recent releases landed on November 1, 2026 and November 7, 2026 respectively.
| Parameter | microTERA | Sirens' Chor |
|---|---|---|
| Price | $1.99 — better | $3.99 |
| Rating | 4.9 (9 ratings) — better | 4.0 (2 ratings) |
| Positive reviews | 81.0% of reviews | 100.0% of reviews — better |
| Number of ratings | 9 — better | 2 |
| Update frequency | Every 4 months — better | Every 39 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPad | iPhone, iPad, iPod — better |
| Requires iOS | 11.0 | 10.0 — better |
| Further details — not scored | ||
| Size | 24 MB | 11 MB |
| Age rating | 4+ | 4+ |
| Developer | Harry Gohs | Aleksandar Mlazev |
Customer experience
microTERA
Sirens' Chor
In-app purchases
microTERA
No in-app purchases
Sirens' Chor
No in-app purchases









