Comparison

iOptigan vs GRFX

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

Head to head
About

iOptigan

Experience the unique lo-fi sound of a vintage optical organ on your iOS device. This app faithfully recreates the original instrument's sound and functionality, allowing you to play chord patterns and explore different musical styles. It includes a virtual spring reverb, metronome, and MIDI capabilities for expanded creative control.

Highlights
  • Authentic lo-fi optical organ sound
  • Virtual spring reverb
  • Optical metronome
  • MIDI in/out and chord detection
  • Sequencer with record/playback
  • Audio and MIDI file sharing
Features
Currently charting
Read full description

This is the Optigan for iOS. The Optigan, short for Optical Organ, was a chord organ from the early 1970’s. It is remembered today for its unique system of sound reproduction using optical discs. These LP-sized film discs were optically encoded with 57 concentric tracks, which contained loops of musical combos playing chord patterns in different styles. Each disc contained a specific style of music (Bossa Nova, Big Band etc) which the user could control by pressing the chord buttons. Changing the discs was as simple as putting a new record on your turntable. Think of it as the 1971 version of GarageBand. Despite this novel technology, the scratchy sound of the Optigan left a lot to be desired. The iOptigan we present here truthfully recreates that lo-fi sound. 25 of the original 40 discs are included, the remaining 15 can be purchased individually or all together in the Complete Pak. Specifications and Features: • Disc loading rigth-side-up or upside-down • Spring Reverb (virtual) • Optical Metronome • Audio Demo for each Disc • MIDI in/out • MIDI chord detection • MIDI File Import • Sequencer with Record and Playback • Sharing for songs as Audio and MIDI File • iTunes File Sharing • Inter-App Audio • Smart background audio • Help overlay • Headphone optimised stereo (optional) • Radio Mode for Chord Buttons or Keyboard • Comfortable speed control in semitones or BPM

About

GRFX

Transform ordinary audio into extraordinary sonic landscapes with real-time granular effects. Slice and reshape sound into evolving textures, rhythmic glitches, and haunting drones using an intuitive pitch controller and extensive modulation options.

Highlights
  • Granular engine for textures and rhythms
  • Harmonic Triangle pitch control
  • Multi-effect chain with probabilistic routing
  • Four self-modulating LFOs
  • Drag-and-drop modulation system
  • Rhythmic synchronization
Features
Read full description

GRFX is a powerful and creative granular effects processor that turns ordinary audio into extraordinary sonic landscapes. Slice your sound into grains and reshape them into evolving textures, shimmering chords, rhythmic glitches, haunting drones, and more. At the heart of GRFX is the Harmonic Triangle – an intuitive 3-way pitch controller that lets you morph simple tones into lush pads, arpeggiated patterns, or abstract gestures. Whether you’re aiming for organic soundscapes or synchronized stutters, GRFX gives you precise control over the flow of grains and modulation. Build complexity with four self-modulating LFOs, a multi-effect chain with probabilistic routing, and an elegant drag-and-drop modulation system. Shape your sound, modulate nearly every parameter, and sculpt immersive audio transformations in real time. Key Features: - Granular engine for creating textures, rhythms, chords, glitches, drones, ambiences, and more - Harmonic Triangle for 3-way pitch control, detuning, and microtonality - Built-in Chord Selector with 32 triads for instant harmonic richness - Grain envelope shaping for plucky, smooth, or abrupt grains - Buffer size, division, sync, and freeze controls - Rhythmic synchronization for tempo-synced effects and patterns - 4 LFOs with self-modulation and drag-and-drop assignment - Modulation panel & view mode for streamlined modulation management - 2 Multi-Effect slots (Filter, Distortion, Delay, Peak EQ, Chorus, Phaser, Bitcrusher, Reverb) with probability-based routing - Dedicated Send FX with Delay and Reverb in series or parallel mode - Flexible mixer section for sculpting wet/dry balance and routing AUv3 Audio Unit plugin – requires an AUv3-compatible host app such as Logic Pro, GarageBand, AUM, or Cubasis. Standalone version included.

Screenshots

iOptigan3 screens
GRFX4 screens

Verdict

The call

The clearest difference is in-app purchases: GRFX at none against iOptigan's 16. iOptigan's advantage is review sentiment (92% vs 78%) and ratings volume (114 vs 10). On rating, ads 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

iOptigan costs $5.99 and GRFX $6.99 up front. iOptigan sells 16 one-off in-app purchases. GRFX asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

iOptigan holds the better App Store score, 4.8 against 4.6. That said, the two scores are not equally well evidenced: iOptigan has 114 ratings behind it against 10, so its average is the more settled of the two. Written reviews point the same way: 92% of iOptigan's written reviews are positive against 78% of GRFX's.

Scorecard7 real differences · 4 level
iOptigan versus GRFX: the parameters behind the verdict, then further details
ParameteriOptiganGRFX
Price$5.99 — better$6.99
Rating4.8 (114 ratings) — better4.6 (10 ratings)
Positive reviews92.2% of reviews — better77.8% of reviews
Number of ratings114 — better10
Update frequency—Every 2 months
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchases — betterPaid
Best chart rank#98 — better—
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS8.0 — better17.0
Further details — not scored
Size179 MB117 MB
Age rating+44+
DeveloperStefan StenzelImaginando Lda

Customer experience

iOptigan

All ratings114 ratings
Positive93.0%
Neutral4.4%
Negative2.6%
Written reviews64 reviews
Positive92.2%
Neutral6.3%
Negative1.6%

GRFX

All ratings10 ratings
Positive90.0%
Neutral0.0%
Negative10.0%
Written reviews9 reviews
Positive77.8%
Neutral0.0%
Negative22.2%

Bugs and requests

iOptigan

Reported bugs

10 issues
  • Stuck/phantom keys on M1 iPad Pro
  • E major plays D Diminished sample
  • Bottom row of controls unresponsive
  • Audio level clipping, especially when slowing playback
  • Left-only headphone audio output
Show 5 more
  • InterApp Audio broken in Garageband
  • InterApp Audio buggy in n-Track Studio Pro
  • App doesn't fill modern screen sizes
  • Vamp loop section bug with 5th switch
  • Gay 90's Waltz disc has incorrect flasher count

Requested features

19 requests
  • Update codebase with AudioKit Engine
  • Allow app to run in background
  • Add AudioUnit Extension support
  • Include newly released sound packs
  • Clarify chord identification methods
Show 14 more
  • AUV3 version
  • Audiobus compatibility
  • Virtual MIDI support
  • Ableton Link support
  • MPE support
  • Stacking discs for combined playback
  • Add Orchestron sounds
  • Add iChliton
  • Add Talentmaker discs
  • Update for larger screen compatibility
  • Export WAV functionality
  • Limit loudness of pops and scratches (equalizer?)
  • Set release of keys
  • MIDI program changes support

GRFX

Not enough reviews yet to summarise bugs or requests.

In-app purchases

16 purchases

iOptigan

One-time16
  • Champagne Music$0.99
  • Country Waltz$0.99
  • Romantic Strings$0.99
Show 13 more
  • Big Top Marching Band$0.99
  • Polynesian Village$0.99
  • Singing Rhythm$0.99
  • Rollin’ Easy$0.99
  • Movin'$0.99
  • Cathedral Organ$0.99
  • Vox Humana$0.99
  • Country Sunshine$0.99
  • Down Home$0.99
  • Gospel Rock$0.99
  • Guitar Boogie$0.99
  • New Orleans Blues$0.99
  • Complete Disc Pak$5.99
None

GRFX

No in-app purchases

Questions

Is iOptigan free?
iOptigan costs $5.99, and also offers in-app purchases.
Is GRFX free?
GRFX costs $6.99, with no in-app purchases.
Which has better reviews, iOptigan or GRFX?
iOptigan is rated higher. iOptigan averages 4.8 out of 5 from 114 ratings, while GRFX averages 4.6 from 10 ratings.
Do iOptigan or GRFX have ads?
Neither iOptigan nor GRFX shows ads.

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