Keyboard Collection vs Sirens' Chor
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Keyboard Collection
Practice playing piano, electric piano, and harpsichord on your mobile device. Features realistic instrument models, 4-octave keyboards, and multitouch support for chords.
- Realistic instrument models
- Interactive 3D view
- 4-octave keyboards
- Multitouch for chords
- Authentic polyphonic sound
- Optional note overlay
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Whether you're a complete beginner or a virtuoso, you can practise on the go with the Keyboard Collection, including Piano, Electric Piano and Harpsichord. Features * Realistic instrument models * Interactive 3D view * 4-octave keyboards * Multitouch for chords * Authentic polyphonic sound * Optional note overlay
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: Keyboard Collection at 4.8 against Sirens' Chor's 4.0. Keyboard Collection also leads on update cadence (every 4 months vs every 39 months) and price ($0.99 vs $3.99). On review sentiment, ratings volume, ads and in-app purchases 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
Keyboard Collection costs $0.99 and Sirens' Chor $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Keyboard Collection holds the better App Store score, 4.8 against 4.0. Both are backed by a comparable volume of ratings — 4 and 2 respectively. Written reviews split almost evenly too, at 100% and 100% positive.
Keyboard Collection ships an update every 4 months, Sirens' Chor every 39 months. The most recent releases landed on November 6, 2026 and November 7, 2026 respectively.
| Parameter | Keyboard Collection | Sirens' Chor |
|---|---|---|
| Price | $0.99 — better | $3.99 |
| Rating | 4.8 (4 ratings) — better | 4.0 (2 ratings) |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| Number of ratings | 4 — better | 2 |
| Update frequency | Every 4 months — better | Every 39 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 8.0 — better | 10.0 |
| Further details — not scored | ||
| Size | 61 MB | 11 MB |
| Age rating | 4+ | 4+ |
| Developer | Robert Swinburn | Aleksandar Mlazev |
Customer experience
Keyboard Collection
Sirens' Chor
In-app purchases
Keyboard Collection
No in-app purchases
Sirens' Chor
No in-app purchases
Questions
Is Keyboard Collection free?
Is Sirens' Chor free?
Which has better reviews, Keyboard Collection or Sirens' Chor?
Do Keyboard Collection or Sirens' Chor have ads?
Which is updated more often, Keyboard Collection or Sirens' Chor?
Other comparisons
