Sirens' Chor vs ERS_DimD
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
ERS_DimD
This audio plugin emulates the classic Roland Dimension D chorus effect, known for its subtle, airy stereo enhancement. It adds presence to sounds without compromising the original audio structure. Enhanced controls offer more flexibility than the original hardware.
- Emulates Roland Dimension D chorus
- Subtle stereoizing effect
- Adds presence and airiness
- Enhanced control options
- Preserves original sound structure
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The ERS DimD chorus audio plugin was originally designed and sold by Harrie Munnik and his Dutch company EmptyRoomSystems. DDMF is proud to carry on the legacy by distributing and further developing the set of ERS plugins. This plug-in has been developed to sound like the Roland Dimension D Chorus with enhanced controls (a hardware chorus that has been used on thousands of recordings worldwide). It has its own signature sound: it is famous for delivering a subtle, stereoizing enhancing, airy effect while adding more presence to a sound. Most chorus products give a lot of modulation and do not keep the original structure of the sound intact. This chorus is way more subtle and adds something rather than take away the original quality of the sound.
Screenshots
Verdict
The clearest difference is price: Sirens' Chor at $3.99 against ERS_DimD's $9.99. ERS_DimD's advantage is update cadence (every 8 months vs every 39 months). On rating, review sentiment, ratings volume and ads 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 ERS_DimD $9.99 up front. Neither carries in-app purchases, so what you see is what you pay.
On the App Store both sit at effectively the same score — 4.0 for Sirens' Chor against 4.0 for ERS_DimD. Both are backed by a comparable volume of ratings — 2 and 5 respectively. Written reviews split almost evenly too, at 100% and 100% positive.
Sirens' Chor ships an update every 39 months, ERS_DimD every 8 months. Both last shipped on November 3, 2026.
| Parameter | Sirens' Chor | ERS_DimD |
|---|---|---|
| Price | $3.99 — better | $9.99 |
| Rating | 4.0 (2 ratings) | 4.0 (5 ratings) |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| Number of ratings | 2 | 5 — better |
| Update frequency | Every 39 months | Every 8 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 10.0 | 9.3 — better |
| Further details — not scored | ||
| Size | 11 MB | 7 MB |
| Age rating | 4+ | 4+ |
| Developer | Aleksandar Mlazev | Christian Siedschlag |
Customer experience
Sirens' Chor
ERS_DimD
In-app purchases
Sirens' Chor
No in-app purchases
ERS_DimD
No in-app purchases









