Comparison

OB vs ButterSynth

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

Head to head
About

OB

This app emulates the classic Oberheim OB-X synthesizer, offering its rich sound and behavior with added enhancements. It focuses on sonic quality and includes micro random detuning for authentic analog warmth. External effects are recommended to further shape its versatile soundscapes.

Highlights
  • Oberheim OB-X emulation
  • Recreates original sound and behavior
  • Added enhancements to original design
  • Micro random detuning
  • Rich and good sound quality
Features
Read full description

OB-Xd is based on the Oberheim OB-X. It attempts to recreate its sound and behavior, but as the original was very limited in some important ways, a number of things were added or altered to the original design. OB-Xd was designed to sound as good and as rich as the original. It implements micro random detuning. Also, like many synths of the OB-X's generation, the OB-Xd has no internal effects so its sounds and textures can be greatly enhanced by the use of additional processing like chorus, reverb, delay, etc.

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
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

OB1 screens
ButterSynth4 screens

Verdict

The call

The clearest difference is rating: OB at 4.4 against ButterSynth's 4.0. OB also leads on price ($14.99 vs $19.99). On review sentiment, ratings volume, update cadence and ads 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

OB costs $14.99 and ButterSynth $19.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

OB holds the better App Store score, 4.4 against 4.0. Both are backed by a comparable volume of ratings — 65 and 63 respectively. Written reviews complicate that: 57% of OB's written reviews are positive against 59% of ButterSynth's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly every 2 months. The most recent releases landed on October 22, 2026 and October 21, 2026 respectively.

Scorecard3 real differences · 7 level
OB versus ButterSynth: the parameters behind the verdict, then further details
ParameterOBButterSynth
Price$14.99 — better$19.99
Rating4.4 (65 ratings) — better4.0 (63 ratings)
Positive reviews57.0% of reviews59.2% of reviews — better
Number of ratings65 — better63
Update frequencyEvery 2 monthsEvery 2 months
AdsNoNo
In-app purchasesNoNo
MonetizationFree — betterPaid
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.014.0 — better
Further details — not scored
Size25 MB468 MB
Age rating4+4+
DeveloperDiscoDSP LLCArto Vaarala

Customer experience

OB

All ratings65 ratings
Positive84.6%
Neutral4.6%
Negative10.8%
Written reviews86 reviews
Positive57.0%
Neutral12.8%
Negative30.2%

ButterSynth

All ratings63 ratings
Positive73.0%
Neutral7.9%
Negative19.0%
Written reviews71 reviews
Positive59.2%
Neutral11.3%
Negative29.6%

User reviews

OB

From 65 App Store ratings

What we love

  • 🎶 Incredible sound quality
  • ✨ Inspiring creative tool
  • 🎹 Faithful emulation of classic synth
  • 🎛️ Great for programming
  • 🎚️ Useful presets

Room to improve

  • 🐛 Unusable UI on older devices
  • 💻 Poor GUI scaling on iPad Pro
  • 🎛️ Controls unresponsive or misaligned
  • 📉 Limited functionality without updates
  • 🤷‍♂️ No clear upgrade path

ButterSynth

From 63 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

OB

Reported bugs

13 issues
  • Crashes in Audiobus
  • Cannot use in MIDI section of Audiobus
  • Preset browser issues (scrolling, cut off banks)
  • Automation bug with cutoff freq
  • UI issues on iPad Pro (buttons misaligned, text cut off)
Show 8 more
  • App suspends on iOS 14
  • No virtual keyboard in standalone app
  • AUv3 crashes when adding second instance
  • UI messed up in AU
  • Knobs don't line up with display
  • Wonky controls
  • Programmer page without menu, cannot save/open patches
  • LFOing filter cutoff jerky

Requested features

19 requests
  • Add last/high priority for mono patches
  • Increase polyphony to 8 voices
  • MIDI Learn functionality
  • Preset browser improvements (categories, scrolling)
  • Adjustable keyboard size
Show 14 more
  • GUI scaling/layout redesign for iPhone
  • Skins for GUI
  • MIDI keyboard in standalone mode
  • Effects
  • Preset manager
  • Zoom functionality for AUv3 on iPhone
  • Fix knob turning bugs
  • Add patch select in DAW apps
  • GUI color scheme options
  • Manual in settings
  • Import presets
  • Layering sounds (like original OBXa)
  • White pinstripes on blue background (cosmetic)
  • Mod wheel customization

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

None

OB

No in-app purchases

None

ButterSynth

No in-app purchases

Questions

Is OB free?
OB costs $14.99, with no in-app purchases.
Is ButterSynth free?
ButterSynth costs $19.99, with no in-app purchases.
Which has better reviews, OB or ButterSynth?
OB is rated higher. OB averages 4.4 out of 5 from 65 ratings, while ButterSynth averages 4.0 from 63 ratings.
Do OB or ButterSynth have ads?
Neither OB nor ButterSynth shows ads.
Which is updated more often, OB or ButterSynth?
OB ships an update every 2 months, and ButterSynth every 2 months. Most recently, OB was updated on October 22, 2026 and ButterSynth on October 21, 2026.

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