Comparison

SynthMaster One vs ButterSynth

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

Head to head
About

SynthMaster One

This powerful wavetable synthesizer app offers an intuitive workflow for creating unique sounds. It features a rich library of wavetables, inspiring presets, and a semi-modular architecture for deep sound design. Easily sync data across devices and integrate with DAWs.

Highlights
  • Wavetable synthesis
  • Semi-modular architecture
  • 650 factory presets
  • AUv3 support
  • Cross-platform cloud sync
  • Real-time modulation feedback
  • 32-step arpeggiator/sequencer
Read full description

SynthMaster One iOS is KV331 Audio's first full blown universal synth app on iOS platform. 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 iOS is a joy. SynthMaster One iOS is feature wise identical to the desktop version except the following: * 16 voice polyphony (32 for the desktop version) * Comes with 650 presets (1250 for the desktop version) FEATURES * Universal App: SynthMaster One is now a universal standalone/AUv3 synth app running on iPhone 7 and above. * 650 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 * Bluetooth LE MIDI Controllers * AirDrop

About

ButterSynth

This powerful synthesizer app offers a hybrid approach, combining wavetable, FM, and sample-based synthesis. Create unique sounds with a vast sonic range, advanced modulation, and a built-in effects rack. It caters to both experienced sound designers and beginners with extensive presets.

Highlights
  • Hybrid 6-oscillator synthesis (wavetable, FM, sample)
  • Built-in wavetable editor
  • FM engine with 4 operators
  • Sample and Granulator engines
  • 32-slot modulation matrix
  • Internal FX rack with 16 modules
  • Extensive preset library
Features
Currently charting
Read full description

ButterSynth is a hybrid 6-oscillator wavetable/FM/sample-based AUV3 and standalone synthesizer with a vast sonic range, from gentle pads to screaming leads and basslines. Mix any combination of wavetable, FM, sample and other synthesis engines for one truly massive sound. For the more advanced users, you'll love using ButterSynth's thoughtfully designed interface, incredibly powerful modulation matrix, fully-featured internal FX rack, factory waveform and sample libraries, and almost limitless scope for fun, experimentation and sound design. For less experienced synth programmers, ButterSynth includes a library of hundreds of ready-to-use presets, sparking your creativity to start making music right away. Headline features include - Mix and match any combination of 6 synthesis engines to either emulate your favourite synths of yester-year or build a synth ready for the future. - Dual-wavetable engines also feature 9 phase modes, wave folding, and deep unison controls modelled on vintage hardware synths. - Built-in wavetable editor gives you the ability to tweak, morph, and hand-draw your own custom wavetables, with each wavetable supporting up to 256 frames. - FM engine offers 4 operators with a selection of 12 modulation paths. Each operator can be loaded with any waveform from the factory or user library, and can also self-modulate via the feedback dial. - Sample and Granulator engines both let you load samples (either imported or from the factory library) and control precisely how they are chopped, triggered and layered. Both also feature the same powerful unison modes available in the WT engine. - Highly configurable 32-slot modulation matrix featuring precise mix/max ranges, self-modulation (via the amount target), plus configurable response curves and layer modes. Simply long-tap any parameter to set it as a Mod destination! - Full suite of versatile control sources which includes: 4x MSEG-style looping curve envelopes, 4x LFOs, 4x step sequencers, X/Y pad with motion recording, 8x Macro dials and a powerful arpeggiator inspired by Kirnu Interactive’s Cream. - The EFX rack lets you build your own insert effects chain using any combination of the 16 built-in FX modules. Modules available at launch include delay, reverb, distortion, chorus, OTT compression etc. Note - FX parameters can also be targeted by the mod matrix, unlocking the possibility to program ‘per voice’ modulated effects. - All presets, wavetables, samples and other settings are stored in the Files app, making bulk import/export, backup and community sharing quick and easy. - All of this is housed in an irresistibly designed 4-tab UI that makes synth programming quick and fun.

Screenshots

SynthMaster One4 screens
ButterSynth4 screens

Verdict

The call

The clearest difference is price: SynthMaster One at $9.99 against ButterSynth's $19.99. SynthMaster One also leads on rating (4.7 vs 4.0) and ratings volume (743 vs 62). ButterSynth's advantage is in-app purchases (none vs 11) and chart position (#190 vs unranked). On review sentiment, update cadence, 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

SynthMaster One costs $9.99 and ButterSynth $19.99 up front. SynthMaster One sells 11 one-off in-app purchases. ButterSynth asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

SynthMaster One holds the better App Store score, 4.7 against 4.0. That said, the two scores are not equally well evidenced: SynthMaster One has 743 ratings behind it against 62, so its average is the more settled of the two. Written reviews point the same way: 64% of SynthMaster One's written reviews are positive against 60% of ButterSynth's.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly every 2 months. The most recent releases landed on September 22, 2026 and September 16, 2026 respectively.

Scorecard7 real differences · 4 level
SynthMaster One versus ButterSynth: the parameters behind the verdict, then further details
ParameterSynthMaster OneButterSynth
Price$9.99 — better$19.99
Rating4.7 (743 ratings) — better4.0 (62 ratings)
Positive reviews63.8% of reviews — better59.6% of reviews
Number of ratings743 — better62
Update frequencyEvery 2 monthsEvery 2 months
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchases — betterPaid
Best chart rank—#190 — better
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS10.0 — better14.0
Further details — not scored
Size402 MB468 MB
Age rating4+4+
DeveloperKV331 AudioArto Vaarala

Customer experience

SynthMaster One

All ratings743 ratings
Positive92.9%
Neutral2.6%
Negative4.6%
Written reviews207 reviews
Positive63.8%
Neutral10.6%
Negative25.6%

ButterSynth

All ratings62 ratings
Positive72.6%
Neutral8.1%
Negative19.4%
Written reviews57 reviews
Positive59.6%
Neutral10.5%
Negative29.8%

User reviews

SynthMaster One

From 743 App Store ratings

What we love

  • 🚀 Powerful synth engine
  • 👍 Extensive preset library
  • 🎨 Versatile sound design capabilities
  • 💡 Free desktop version expansions on iPad
  • 🎹 Excellent sound quality and tone

Room to improve

  • 🐛 Crashes and stability issues
  • 🔋 Battery drain in background
  • 🤔 Confusing in-app purchase system
  • 👎 UI/UX could use improvement
  • 🔇 Audio issues and no sound

ButterSynth

From 62 App Store ratings

What we love

  • ✨ Deep sound design capabilities
  • 🎛️ Versatile modulation matrix
  • 🔊 Great sound quality
  • 💡 Innovative wavetable generator
  • 🌟 Serum-like experience

Room to improve

  • 📱 Fiddly on small screens
  • 🐛 Crashes frequently
  • 🐛 Disappears in Cubasis
  • 🐛 Spikes CPU usage
  • 🐛 Crashes on patch change

Bugs and requests

SynthMaster One

Reported bugs

4 issues
  • Stuck notes and MIDI issues
  • Preset loading crashes
  • Restore purchases not working
  • Incompatibility with certain DAWs

Requested features

4 requests
  • Add custom wavetable support
  • Improve MIDI mapping and MPE functionality
  • Optimize performance on older devices
  • Streamline preset management and browsing

ButterSynth

Reported bugs

39 issues
  • App crashing with AUM
  • Disappears in Cubasis randomly
  • Crashes all the time inside Logic
  • Changing a patch spikes CPU to 99%
  • Crashes on every patch change
Show 34 more
  • No audio when rendering or freezing track
  • Keyboard doesn't load on iPhone
  • iOS18 broke ButterSynth (audio recording issues)
  • Failed to load as Auv3
  • Crashes as soon as a preset is selected
  • Some patches hanging/sounding without input
  • CPU spikes to 100% on preset switching
  • Audio crackles on preset switching
  • Sample module has consistent buzz
  • LFOs are extremely simple (no phase offset)
  • Square wave LFO is not square (has slew)
  • Step sequencer always has glide/slew
  • Cannot save custom presets
  • No undo function in wave table editor
  • AUv3 plugin resets when ButterSynth crashes
  • Does not show up as auv3 in Cubasis, AUM, or Audio Evolution
  • Crashes regularly even on newest iPad
  • Preset changes every time play is pressed
  • Not resizing appropriately on smaller screens
  • Crashes with unison function in AUM
  • White noise on crash with unison
  • Sound continues after song stops in GarageBand
  • Preset changes on stop, rewind, or play in GarageBand
  • Keeps crashing in GarageBand (AUv3)
  • Patches in standalone sound different as AUv3
  • Crashes when hitting play with arpeggiator/sequencer on iPhone
  • No keyboard appears in iPhone standalone mode
  • Audio Unit Extension quit error on export
  • Lots of crashes in standalone and hosted in AUM
  • MIDI not working
  • Automation still doesn’t work in Logic Pro
  • Random LFO is great for recording sequences
  • Preset browser closes each time a new preset is selected
  • Works as AUv3 after starting in standalone mode

Requested features

20 requests
  • MPE popup possible on top of the auv3
  • Button to hide built-in keyboard
  • Buffer size option
  • Additional MIDI mappings (e.g., arpeggiator toggle)
  • Sustain pedal support
Show 15 more
  • Longer LFO speed for evolving soundscapes
  • Alternative skins/color themes
  • Pinable preset browser
  • Virtual keyboard to remain active while browser is pinned
  • Make app take up whole screen (no black borders)
  • Master detune
  • Parameter lock
  • More presets
  • Fix square wave LFO to be truly square
  • Fix step sequencer glide/slew for discrete steps
  • Undo function in wave table editor
  • Filter key follow button
  • Adjust envelope curves (especially release)
  • Easier way to adjust modulation matrix amount
  • Phase distortion inclusion

In-app purchases

11 purchases

SynthMaster One

One-time11
  • BigTone Club Construction Set$4.99
  • True Trance Sounds Volume 1$4.99
  • Vandalism Future House$4.99
Show 8 more
  • NatLife Retrowave Sounds Vol.1$4.99
  • Demis Hellen Euphoric Trance$4.99
  • Venus Theory Trap Sounds$4.99
  • Vandalism Shocking Future Bass$4.99
  • NatLife Progressive&Deep Vol.1$4.99
  • Bluffmunkey Cinematic Sounds$4.99
  • Desktop Presets Upgrade$7.99
  • SM One Expansions Bundle$24.99
None

ButterSynth

No in-app purchases

Questions

Is SynthMaster One free?
SynthMaster One costs $9.99, and also offers in-app purchases.
Is ButterSynth free?
ButterSynth costs $19.99, with no in-app purchases.
Which has better reviews, SynthMaster One or ButterSynth?
SynthMaster One is rated higher. SynthMaster One averages 4.7 out of 5 from 743 ratings, while ButterSynth averages 4.0 from 62 ratings.
Do SynthMaster One or ButterSynth have ads?
Neither SynthMaster One nor ButterSynth shows ads.
Which is updated more often, SynthMaster One or ButterSynth?
SynthMaster One ships an update every 2 months, and ButterSynth every 2 months. Most recently, SynthMaster One was updated on September 22, 2026 and ButterSynth on September 16, 2026.

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