Comparison

RM vs FormKey

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

RM

This audio effect app offers versatile modulation capabilities, including ring, amplitude, phase, and frequency modulation. It features a built-in carrier oscillator, multimode filter, envelope follower, and LFO for creating unique sounds. It can be used standalone or with other audio apps.

Highlights
  • Multiple modulation types (Ring, AM, FM, Phase)
  • Built-in carrier oscillator
  • Multimode filter (LP, HP, BP)
  • Envelope follower and LFO
  • Standalone and IAA/Audiobus support
  • AUv3 plugin compatibility
Features
Read full description

RM-1 Wave Modulator RM-1 is a multi purpose audio effect designed around various types of modulation. Featuring a built-in carrier oscillator, multimode filter, envelope follower and low frequency oscillator, RM-1 creates new sounds by combining carrier waveform and the audio input in different ways. Types of modulation: - Ring Modulation (virtual analog) - Ring Modulation (digital) - Amplitude Modulation - Phase Modulation (DX-style FM) - Frequency Modulation (linear) Overview: - Built-in carrier oscillator with variable wave-shape (sine->square) - Built-in multimode Filter (LP, HP, BP) - Built-in Envelope Follower and LFO Connectivity: - Standalone (MIC, USB audio) - IAA / Audiobus - AUv3 Plugin

About

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.

Highlights
  • Shape-based note input
  • Color-coded octaves
  • Isomorphic key layout
  • Pattern recognition aid
  • Chord discovery assistance
  • Future update commitment
Features
Read full description

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 from your own device into something new. Slicing, shaping, and rearranging samples feel effortless instead of technical. • Pn0 is a modeled piano designed to sound rich while being incredibly simple to use • 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.

Verdict

The call

The clearest difference is price: FormKey at Free against RM's $9.99. FormKey also leads on update cadence (fortnightly vs every 10 months). RM's advantage is in-app purchases (none vs 1) and rating (4.6 vs 4.3). On ads, monetization model and device support 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

CostPrice · In-app purchases · Ads · Monetization

FormKey is free to download; RM costs $9.99 up front. FormKey sells 1 one-off in-app purchase. RM asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

RM holds the better App Store score, 4.6 against 4.3. Both are backed by a comparable volume of ratings — 18 and 6 respectively. Written reviews point the same way: 67% of RM's written reviews are positive against 50% of FormKey's.

UpkeepUpdate frequency

RM ships an update every 10 months, FormKey fortnightly. Both last shipped on September 19, 2026.

Scorecard7 real differences · 3 level
RM versus FormKey: the parameters behind the verdict, then further details
ParameterRMFormKey
Price$9.99Free — better
Rating4.6 (18 ratings) — better4.3 (6 ratings)
Positive reviews66.7% of reviews — better50.0% of reviews
Number of ratings18 — better6
Update frequencyEvery 10 monthsFortnightly — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationPaidPaid
DevicesiPadiPad
Requires iOS9.0 — better18.6
Further details — not scored
Size35 MB86 MB
Age rating4+4+
DeveloperKai ArasPolyhedra

Customer experience

RM

All ratings18 ratings
Positive94.4%
Neutral0.0%
Negative5.6%
Written reviews6 reviews
Positive66.7%
Neutral0.0%
Negative33.3%

FormKey

All ratings6 ratings
Positive66.7%
Neutral33.3%
Negative0.0%
Written reviews6 reviews
Positive50.0%
Neutral33.3%
Negative16.7%

In-app purchases

None

RM

No in-app purchases

1 purchases

FormKey

One-time1
  • FormKey Full Unlock$14.99

Questions

Is RM free?
RM costs $9.99, with no in-app purchases.
Is FormKey free?
FormKey is free to download, with in-app purchases available.
Which has better reviews, RM or FormKey?
RM is rated higher. RM averages 4.6 out of 5 from 18 ratings, while FormKey averages 4.3 from 6 ratings.
Do RM or FormKey have ads?
Neither RM nor FormKey shows ads.
Which is updated more often, RM or FormKey?
RM ships an update every 10 months, and FormKey fortnightly. Most recently, RM was updated on September 19, 2026 and FormKey on September 19, 2026.

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