RF vs FormKey
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
RF
This app offers a versatile collection of algorithmic reverbs for creating diverse soundscapes, from intimate rooms to expansive modulated spaces. It features multiple reverb programs, extensive tweakable controls, and seamless integration with various audio hosts and interfaces.
- Multiple reverb programs
- Continuously variable size
- Variable pre-delay
- Diffusion and damping controls
- Modulation section
- AudioUnitV3, Inter-App Audio, Audiobus support
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RF-1 - Algorithmic Reverb (AU, AB, IAA, Standalone) RF-1 is a collection of algorithmic reverbs capable of creating a variety of effects ranging from small rooms to huge, heavily modulated spaces and everything in between. RF-1 comes packed with multiple reverb algortihms, a solid standalone application, carfully tuned factory presets and a plethora of tweak-able controls. What's more, RF-1 integrates with everything from AudioUnit Hosts over Audiobus to Inter-App Audio, Guitar- and USB Interfaces. Features: * 5 unique reverb programs (see below) * Continuously variable size * Variable pre-delay * Diffusion control * Damping control * Width control * High- and Low shelves (+/- 6db pre effect) * Mod section with depth and speed controls (Sine LFO 0.01hz to 5.0hz) Programs: 1. Hall Clean and bright sounding space with subtile modulation and gradually building density. 2. Plate Dark, highly diffused sound with high initial echo density and dark modulation. 3. EnsembleVerb Capable of huge, wide spaces with deep modulation. 4. TremoloVerb Large, bright and always moving with amplitude modulation at the output. 5. VintageVerb Dark, noisy and wonderfull sounding reverb modeled after the first digital reverbs from the late 70s. (10khz bandwidth / 12bit processing) Connectivity: * AudioUnitV3 Effect * Inter-App Audio Effect * Audiobus (Filter) * Ableton Link * USB Audio Interface (Standalone) * Guitar Interface (Standalone) * Microphone (Standalone)
FormKey
This app is an intuitive MIDI controller that helps musicians improve by using shapes for notes and colors for octaves. Its unique isomorphic keys aid in pattern recognition and chord discovery, making music creation more accessible.
- Shape-based note input
- Color-coded octaves
- Isomorphic key layout
- Pattern recognition aid
- Chord discovery assistance
- Future update commitment
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Unlock your music potential. FormKey is the first music suite that helps you become the musician you've always imagined being, just by using it. INTRODUCING FORM Form is a new way to read and create music. Notes become shapes. Octaves become colors. Duration becomes a simple to read fraction. You can learn to read and play music in minutes. FormKey is the first release of the Form notation language, an open licensed music language designed to create instant music literacy. With the goal being to become a standard you'll see everywhere. THREE MODES: CREATE, LEARN, AND CONTROL • Create mode gives you a 16-track sequencer built on the classic drum machine workflow, modernized for today. Use your own AUv3 plugins or the three we built in to create full tracks from the ground up. • Learn lets you play and read your way through classical pieces while Form teaches you exactly what the music is doing, note by note. • Control turns FormKey into a MIDI controller for your external workflows, so it fits right into the setup you already have. THREE BRAND NEW AUv3 PLUGINS • Tone is a fully interactive subtractive synth that makes synthesis make sense. Every knob and connection is something you can hear and understand, so the architecture of a sound stops being a mystery. • Wave is a file-based sampler that lets you chop audio samples from your device, designed to make Slicing, and rearranging samples feel effortless instead of technical. • Patt3rn is a suite of modeled instruments curated to provide users with high quality options when looking for go to sounds every sequencer needs. • All 3 work in any host, so the instruments you learn in FormKey come with you wherever you go. SCALE MODE Reshape the keyboard to any of 26 scales, so every note you play stays in key. Choose from: • Major and minor: Major, Natural Minor, Melodic Minor, Harmonic Minor • Modes: Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, Locrian • Pentatonic and blues: Major Pentatonic, Minor Pentatonic, Blues • Symmetric: Whole Tone, Whole-Half Diminished, Half-Whole Diminished, Augmented Hexatonic • World and exotic: Hungarian Minor, Neapolitan Minor, Byzantine, Enigmatic, Hirajoshi, In Sen, Kumoi, Iwato We've refined the interface across the app, making FormKey easier and more enjoyable to use. Every feature in FormKey is free to try. In celebration of our launch, $14.99 unlocks everything for the life of the app. We hope you love it as much as we do.
Screenshots
Verdict
The clearest difference is price: FormKey at Free against RF's $5.99. FormKey also leads on update cadence (fortnightly vs every 8 months). RF's advantage is in-app purchases (none vs 1) and review sentiment (67% vs 57%). On rating, ratings volume, ads 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
FormKey is free to download; RF costs $5.99 up front. FormKey sells 1 one-off in-app purchase. RF asks for nothing beyond the download.
On the App Store both sit at effectively the same score — 4.6 for RF against 4.5 for FormKey. Both are backed by a comparable volume of ratings — 12 and 8 respectively. Written reviews are what separate them: 67% of RF's written reviews are positive against 57% of FormKey's.
RF ships an update every 8 months, FormKey fortnightly. The most recent releases landed on November 6, 2026 and November 3, 2026 respectively.
| Parameter | RF | FormKey |
|---|---|---|
| Price | $5.99 | Free — better |
| Rating | 4.6 (12 ratings) — better | 4.5 (8 ratings) |
| Positive reviews | 66.7% of reviews — better | 57.1% of reviews |
| Number of ratings | 12 — better | 8 |
| Update frequency | Every 8 months | Fortnightly — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, iPod — better | iPad |
| Requires iOS | 9.0 — better | 18.6 |
| Further details — not scored | ||
| Size | 15 MB | 88 MB |
| Age rating | 4+ | 4+ |
| Developer | Kai Aras | Polyhedra |
Customer experience
RF
FormKey
In-app purchases
RF
No in-app purchases
FormKey
- FormKey Full Unlock$14.99









