Comparison

SK vs SynthMaster One for iPhone

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

Head to head
About

SK

Experience the nostalgic sound of an 80s lo-fi sampler keyboard. This app recreates the iconic Casio SK-1 with sampling capabilities, a drum machine, and a variety of instruments. Explore demo patterns, record your voice, and create music with a vintage feel.

Highlights
  • Sampling features
  • Onboard drum machine
  • Multiple instruments
  • Demo drum patterns
  • Live recording (full version)
  • Audio Unit support
  • MIDI support
Read full description

SK-51 is Fingerlab's all-in-one emulation of the Casio SK-1 and SK-5 — an 8-bit lo-fi keyboard from the 80s with sampling features and onboard drum machine, available for iPhone, iPad & Mac. Called the "poor man's sampler" in its time, this iconic Casio keyboard was used by Fatboy Slim, Portishead, Autechre and Nine Inch Nails — and now it fits in your pocket. At Fingerlab, some of us composed our first songs with it as kids in the eighties. We wanted to bring back that unique feeling, so we built SK-51: a faithful recreation of the Casio SK-1 and VL-Tone, recorded note by note at professional audio quality (16bit / 44.1kHz). SK-51 is a universal purchase — one buy covers iPhone, iPad & Mac. Sample your voice, fire up the drum machine, play a chord — and you've got a track. Free version includes: • 3 instruments (Flute, Piano, Trumpet) • 14 drum kits & 6 drum pads • 4 sampling slots • 3 demo drum patterns • Full Mixer • AUv3 Audio Unit • Full MIDI & MIDI Mapping support • AudioBus & Inter-App Audio (iOS) • Ableton Link support Full Version (IAP) includes: • 19 instruments (Brass Ensemble, Vibraphone, Chorus and more) • 21 demo drum patterns • 5 FX: Tube Amp, Phaser, Delay, Reverb & Compressor • Live Recording Questions or feedback? We'd love to hear from you: contact@fingerlab.net Stay tuned! The Fingerlab Team

About

SynthMaster One for iPhone

This powerful wavetable synthesizer app offers an intuitive workflow for creating new sounds. It features a rich library of wavetables, inspiring factory presets, and real-time modulation feedback for sound design.

Highlights
  • Wavetable synthesis
  • 300 factory presets
  • AUv3 support
  • Files App integration
  • Real-time modulation feedback
  • Semi-modular architecture
  • 32-step arpeggiator/sequencer
Read full description

SynthMaster One for iPhone is KV331 Audio's first full blown synth app for iPhone. It's a powerful wavetable synth with an intuitive workflow. With its simple layout, rich wavetable/waveform content and inspiring factory presets library, designing new sounds with SynthMaster One for iPhone is a joy. SynthMaster One for iPhone is feature wise identical to the desktop version except the following: * 8 voice polyphony (32 for the desktop version) * Comes with 300 presets (1250 for the desktop version) FEATURES * 300 Factory Presets: SynthMaster One iOS comes with inspiring factory presets from a world class team of sound designers: Arksun, Aiyn Zahev, BigTone Studios, Brian Transeau, Bluffmunkey, Bulent Biyikoglu, Gercek Dorman, Dejavu Sound, Fragment Audio, Kurt Ader, Mirko Ruta, Nori Ubukata, Rob Lee, Ufuk Kevser, Selcuk Ergen, The Machine, Vandalism Sound, Venus Theory, Vorpalsound and Xenos Soundworks * AUv3: SynthMaster One iOS supports AudioUnits V3, allowing multiple instances to run under supporting DAW apps like GarageBand, Cubasis or Beat Maker. * Files App Integration: Easily import/export presets, waveforms or scales using the common file browser UI (requires iOS 11+). * Real-time Modulation Feedback: See in real-time how modulation sources and targets change. This is a very helpful feature when designing sounds! * Cross Platform Cloud Synchronization: Easily synchronize your SynthMaster One related data across multiple platforms (Windows, MacOS, iPad, iPhone) * Semi-Modular Architecture: For each SynthMaster One instance, there are 2 oscillators with 2 sub oscillators, 2 Filters, 4 ADSR Envelopes, 3 LFOs, a powerful 16 step arpeggiator/sequencer and also 11 different effects that can be inserted on to 6 FX insert slots. The sub oscillators can be connected to the oscillators in 5 different modes which let you use it as a regular sub oscillator or do complex modulations such as ring modulation, amplitude modulation, phase modulation or frequency modulation. * 32 Step Arpeggiator/Sequencer: The arpeggiator in SynthMaster One features classic arpeggiator modes such as Up, Down, UpDown, DownUp, UpDown2, DownUp2, AsPlayed as well as Sequence, Chord and Arpeggiate modes. * Wavetable Synthesis: SynthMaster One implements true wavetable synthesis which opens up new possibilities for sound design. It comes with a rich content library with hundreds of waveforms and wavetables. * Stereo Oscillators with up to 16 voices Unison: Each of the 2 oscillators in SynthMaster One have stereo output, and can have up to 16 voices "unison". Using the "voices", "voices mix", "detune curve", "detune spread", "pan stread", "tone spread" and "phase spread" parameters, each oscillator can generate a rich "supersaw" type sound. * Zero Delay Feedback Filters: All of the 4 filter categories in SynthMaster One are developed using the zero delay feedback filter technology. With advanced filter parameters like input gain, drive, acid, filter nonlinearities and up to 4 times oversampling you can get that "analog" sound from the filters! * Rich Set of Effects: SynthMaster One features 11 different effect types: Distortion, LoFi, Ensemble, Phaser, 6 Band EQ, Compressor, Vocoder, Delay, Chorus, Tremolo, Reverb. * Microtuning: SynthMaster One supports Scala tuning, so tuning can be set either for each preset or globally by loading from a Scala tuning file. SynthMaster One comes with 300+ scales ranging from 5 note equal tempered scales to 12 note alternate tuning scales. * Preset Browser: SynthMaster One features a comprehensive preset browser with separate search criterias for instrument type, preset attributes, music style or preset author. SUPPORTS * All 64-bit iPad devices * AUv3 Audio Unit Extensions * Note-per-channel MIDI controllers (MPE) * Ableton Link * Interapp Audio and AudioBus * Bluetooth LE MIDI Controllers * AirDrop

Screenshots

SK4 screens
SynthMaster One for iPhone4 screens

Verdict

The call

The clearest difference is rating: SynthMaster One for iPhone at 4.7 against SK's 4.1. SynthMaster One for iPhone also leads on update cadence (every 2 months vs every 4 months) and review sentiment (63% vs 55%). SK's advantage is device support (4 vs 2). On price, ads, in-app purchases 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. SK sells 1 one-off in-app purchase and SynthMaster One for iPhone sells 10 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

SynthMaster One for iPhone holds the better App Store score, 4.7 against 4.1. Both are backed by a comparable volume of ratings — 108 and 335 respectively. Written reviews point the same way: 55% of SK's written reviews are positive against 63% of SynthMaster One for iPhone's.

UpkeepUpdate frequency

SK ships an update every 4 months, SynthMaster One for iPhone every 2 months. The most recent releases landed on November 2, 2026 and November 7, 2026 respectively.

Scorecard6 real differences · 4 level
SK versus SynthMaster One for iPhone: the parameters behind the verdict, then further details
ParameterSKSynthMaster One for iPhone
PriceFreeFree
Rating4.1 (108 ratings)4.7 (335 ratings) — better
Positive reviews54.8% of reviews63.1% of reviews — better
Number of ratings108335 — better
Update frequencyEvery 4 monthsEvery 2 months — better
AdsNoNo
In-app purchasesYesYes
MonetizationFree with in-app purchasesFree with in-app purchases
DevicesiPhone, iPad, iPod, Mac — betteriPhone, iPod
Requires iOS15.010.0 — better
Further details — not scored
Size286 MB297 MB
Age rating4+4+
DeveloperFingerlabKV331 Audio

Customer experience

SK

All ratings106 ratings
Positive76.4%
Neutral5.7%
Negative17.9%
Written reviews62 reviews
Positive54.8%
Neutral11.3%
Negative33.9%

SynthMaster One for iPhone

All ratings331 ratings
Positive94.9%
Neutral2.1%
Negative3.0%
Written reviews65 reviews
Positive63.1%
Neutral6.2%
Negative30.8%

User reviews

SK

From 108 App Store ratings

What we love

  • 🎶 Amazing sound quality
  • 👍 Easy to use
  • 💡 Great for GarageBand
  • 🤩 Nostalgic and retro vibe
  • 💰 Good value for money

Room to improve

  • 💰 Paywalls and locked features
  • 📉 Instability and crashes
  • 🚫 MIDI mapping complexity
  • 🤔 Limited free version functionality
  • 🎛️ Some features not working

SynthMaster One for iPhone

From 335 App Store ratings

What we love

  • ✨ Excellent sound quality
  • 🤩 Incredible features for free
  • 👍 Easy to use interface
  • 🎛️ Versatile sound design capabilities
  • 🎵 Great for GarageBand integration

Room to improve

  • 🐛 Frequent crashes
  • 🔌 Issues with GarageBand integration
  • 💸 In-app purchase problems
  • 🔄 Presets not saving
  • 📉 App appears abandoned

Bugs and requests

SK

Reported bugs

17 issues
  • App crashes when changing rhythms
  • MIDI for desktop stopped working
  • App quits automatically on Intel machines
  • Crashes on start on iPad Pro / iPad OS 15
  • No output when recording
Show 12 more
  • Can't record individual drum sounds in Cubasis
  • Update removed full version purchase
  • AU won't open in NanoStudio 2
  • App crashes when hitting sample buttons or recording
  • Can't upload sample files
  • Game closes every time a sample is recorded
  • App crashes and disappears when selecting sample buttons
  • Not working in Cubasis - iOS 12.1.4
  • Keeps crashing
  • Sampler input works but not output
  • App crashes when trying to open
  • Won't open in BeatMaker 3

Requested features

17 requests
  • AAX or AU version for DAW
  • Bluetooth compatibility for speakers
  • Tap tempo feature
  • Separate FX for drums and keyboard
  • Rhythm fill-in button
Show 12 more
  • Ability to upload edited samples
  • Original SK-1 chord patterns
  • More sample memory for user samples
  • MIDI control for sampler and pads
  • Pitch control in AU mode
  • Play button in AU mode
  • More trigger pads like SK-5
  • Sustain for sounds
  • Different attack envelopes
  • Allow sample to play at same speed regardless of pitch
  • Prevent samples from clicking in loop mode
  • Version of CZ 101/1000 app

SynthMaster One for iPhone

Reported bugs

10 issues
  • App crashes when loading saved presets
  • App crashes when setting default sound
  • AUv3 option disappears in GarageBand
  • Inability to reload user patches without crashing
  • Inability to purchase certain IAP packs
Show 5 more
  • Cells don't save, revert to first synth
  • App doesn't function or open in GarageBand
  • Every note is 1 note or lower
  • GUI is cut off on iPhone SE
  • IAA not loading in FL mobile

Requested features

10 requests
  • Fix in-app purchase issues
  • Improve GarageBand AUv3 stability
  • Enable saving of custom presets
  • Address crashing when loading presets
  • Fix note pitch issues
Show 5 more
  • Ensure app is not abandonware
  • Improve UI scaling on smaller screens
  • Fix wavetable scrolling issues
  • Make IAA work properly
  • Allow recording of music

In-app purchases

1 purchases

SK

One-time1
  • Full Version$9.99
10 purchases

SynthMaster One for iPhone

One-time10
  • BigTone Club Construction Set$4.99
  • True Trance Sounds Volume 1$4.99
  • Vandalism Future House$4.99
Show 7 more
  • NatLife Retrowave Sounds Vol.1$4.99
  • Demis Hellen Euphoric Trance$4.99
  • NatLife Progressive&Deep Vol.1$4.99
  • Vandalism Shocking Future Bass$4.99
  • Venus Theory Trap Sounds$4.99
  • Desktop Presets Upgrade$9.99
  • SM One Expansions Bundle$24.99

Questions

Is SK free?
SK is free to download, with in-app purchases available.
Is SynthMaster One for iPhone free?
SynthMaster One for iPhone is free to download, with in-app purchases available.
Which has better reviews, SK or SynthMaster One for iPhone?
SynthMaster One for iPhone is rated higher. SK averages 4.1 out of 5 from 108 ratings, while SynthMaster One for iPhone averages 4.7 from 335 ratings.
Do SK or SynthMaster One for iPhone have ads?
Neither SK nor SynthMaster One for iPhone shows ads.
Which is updated more often, SK or SynthMaster One for iPhone?
SK ships an update every 4 months, and SynthMaster One for iPhone every 2 months. Most recently, SK was updated on November 2, 2026 and SynthMaster One for iPhone on November 7, 2026.

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