Comparison

iSEM Synthesizer vs Zeeon synth

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

Head to head
About

iSEM Synthesizer

This app is a touch-based emulation of the classic 1974 Oberheim SEM synthesizer, known for its warm analog sounds. It offers a wide range of sonic possibilities, from fat basses to lively leads, and includes over 500 preset sounds.

Highlights
  • Classic Oberheim SEM emulation
  • Two oscillators with PWM
  • 12dB/oct multi-mode filter
  • Added LFO, Noise, Sub oscillator, Arpeggiator, Portamento
  • Polyphonic playability
  • 500+ preset sounds
  • MIDI and AudioUnit v3 support
Features
Read full description

COMPATIBILITY Apple’s AudioUnit v3, Inter-App Audio connectivity, AudioBus 3, Korg’s WIST and Apple’s CoreMIDI are all supported. Furthermore, iSEM is fully compatible with the Audio Unit Extension format. It can be directly launched in any Audio Unit host applications. DESCRIPTION iSEM is a recreation of the classic 1974 Oberheim SEM (Synthesizer Expander Module), one of the world's first self-contained synthesizer modules and the first to bear the "Oberheim Electronics" name. The Oberheim SEM was made famous by artists and bands such as Lyle Mays, Jan Hammer, Joseph Zawinul, Supertramp, 808 State, Vince Clarke and Depeche Mode. Based on the TAE® technology found in our Oberheim SEM V software, iSEM brings back the sound and special characteristics of this iconic synth in an sonically accurate and expanded touch-based emulation. What you can do with the iSEM? The iSEM is a powerful instrument capable of producing a wide range of warm analog sounds.  Reproducing the unique SEM architecture, with its oscillator sync, characteristic filter shape and specific envelope response, the iSEM is able to generate the fat basses that have made the Oberheim brand so popular. Thanks to its simple and clever PW and pitch modulations, it is also very easy to produce moving and lively leads. Its remarkable 12 dB/oct multimode filter is a real blast from the past, becoming an awesome weapon in the context of current electronic music. This unique module can instantly tailor your sound to fat, crisp, or spectral textures with access to all the nuances in between… iSEM comes with over 500 sounds that you can browse through and play. You can also easily create your own sounds with the easy to use interface. Play iSEM's numerous sounds from the iPad keyboard or control iSEM from a MIDI keyboard or other app via CoreMIDI and integrate it into your studio or live performance. If you are an owner of of the Arturia SEM V software on your Mac or PC, you can even import and export sounds between your laptop or desktop SEM V and iSEM. FEATURES All the original parameters of the Oberheim SEM: two oscillators, each offering sawtooth wave and variable-width pulse wave with PWM, sine wave LFO, 12dB/oct multi-mode Filter with low-pass, high-pass, band-pass and notch, two ADS envelope generators. Added functionalities: New LFO, Noise, Sub oscillator, Arpeggiator, Portamento. Polyphonic playability 8 Voice Programmer module allows each voice to have different settings HOLD and CHORD modes. Virtual Analog Chorus. Virtual Analog Delay. Full user MIDI mapping of panel controls. Supports WIST sync to other iOS devices. Support of AudioUnit Extension, AudioBus 3 and Apple’s Inter-App Audio connectivity. The Oberheim™ name used here is a trademark of the Gibson Guitar Corp. The trademark is used by license to Arturia.

About

Zeeon synth

This app is a virtual analog synthesizer that recreates the sound and feel of classic hardware. It features a detailed circuit-modeling engine, powerful modulation, and multiple filter models for rich, organic soundscapes. Explore a vast array of presets and expand your sonic palette with additional sound banks.

Highlights
  • Circuit-modeling engine
  • Powerful modulation matrix
  • Dual oscillators with variable waveforms
  • Multiple filter models
  • Built-in effects unit
  • Audio Unit v3 support
  • Polyphonic step sequencer
Features
Read full description

Zeeon is a virtual-analog synthesizer built on a deeply detailed circuit-modeling engine. We’ve studied classic and modern analog synths to uncover what gives them their unmistakable character and recreated that essence with precision. The result is a unique instrument that delivers the warmth, movement, and organic depth of true hardware. While many emulations sound flat, Zeeon breathes. Every note is alive, with tight lows and shimmering highs. All audio and modulation are processed at 176 kHz (4× oversampling) for uncompromised quality across the entire spectrum. “Desktop-class sound engine … fidelity of this analog emulation goes beyond everything else on iOS.” – App Store review Features • Audio Unit v3 and standalone application with a simple polyphonic step sequencer • Powerful modulation matrix offering self-modulation and cross-layer modulation, 8 modulation slots, 17 signal sources and 41 targets available, both from modulation modules and audio signal path. This takes Zeeon into semi-modular territory. Imagine oscillator waveform, panning, filter cutoff, resonance or LP-HP mode modulated by oscillators or another layer! • 2 oscillators with continuously variable waveforms, hard-sync and sub-oscillator. Carefully simulated analog drift and PSU influence. • Filter: 3 models available: Transistor ladder low pass, OTA cascade low pass and State Variable Filter with continuously variable LP-HP + BP mode. • 2 low frequency oscillators and envelope generators per voice. • Overdrive: diode clipper, transistor saturation, wave folder, pre and post filter. • Up to 2 layers per voice. Layers can modulate each other. • Effects unit: Circuit modelled BBD chorus, bass booster, zero-delay Phaser, Stereo delay and Reverb. • 280 presets and Tutorials bank. 3 additional banks available as IAPs. Full manual and audio demos available at the BeepStreet website.

Screenshots

Zeeon synth3 screens

Verdict

The call

The clearest difference is rating: Zeeon synth at 4.8 against iSEM Synthesizer's 4.1. Zeeon synth also leads on update cadence (every 2 months vs every 5 months) and device support (3 vs 1). iSEM Synthesizer's advantage is in-app purchases (none vs 3) and price ($9.99 vs $14.99). On review sentiment 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

iSEM Synthesizer costs $9.99 and Zeeon synth $14.99 up front. Zeeon synth sells 3 one-off in-app purchases. iSEM Synthesizer asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Zeeon synth holds the better App Store score, 4.8 against 4.1. Both are backed by a comparable volume of ratings — 60 and 209 respectively. Written reviews point the same way: 74% of iSEM Synthesizer's written reviews are positive against 76% of Zeeon synth's.

UpkeepUpdate frequency

iSEM Synthesizer ships an update every 5 months, Zeeon synth every 2 months. The most recent releases landed on October 23, 2026 and October 29, 2026 respectively.

Scorecard8 real differences · 2 level
iSEM Synthesizer versus Zeeon synth: the parameters behind the verdict, then further details
ParameteriSEM SynthesizerZeeon synth
Price$9.99 — better$14.99
Rating4.1 (60 ratings)4.8 (209 ratings) — better
Positive reviews73.7% of reviews76.0% of reviews — better
Number of ratings60209 — better
Update frequencyEvery 5 monthsEvery 2 months — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationPaidFree with in-app purchases — better
DevicesiPadiPhone, iPad, iPod — better
Requires iOS12.1 — better15.6
Further details — not scored
Size80 MB27 MB
Age rating4+4+
DeveloperArturiaBeepStreet

Customer experience

iSEM Synthesizer

All ratings60 ratings
Positive75.0%
Neutral8.3%
Negative16.7%
Written reviews243 reviews
Positive73.7%
Neutral9.1%
Negative17.3%

Zeeon synth

All ratings209 ratings
Positive93.8%
Neutral2.4%
Negative3.8%
Written reviews167 reviews
Positive76.0%
Neutral7.2%
Negative16.8%

User reviews

iSEM Synthesizer

From 60 App Store ratings

What we love

  • 🎹 Fantastic sound quality
  • 💯 Faithful to the original Oberheim SEM
  • 🎨 Versatile sound design capabilities
  • 🎚️ Intuitive and responsive interface
  • 🔊 Rich, warm, and analog-like tones

Room to improve

  • 🐛 Frequent crashes and stability issues
  • 🔌 Poor integration with DAWs and MIDI controllers
  • 🕰️ Slow preset loading times
  • 🔇 Limited modulation options compared to hardware
  • 🤔 Uninspiring factory presets

Zeeon synth

From 209 App Store ratings

What we love

  • 🎨 Excellent sound quality
  • 🎹 Intuitive and well-designed interface
  • 🔧 Flexible and deep sound design capabilities
  • 💻 Seamless integration as an AUv3 plugin
  • 🎚️ Smooth and responsive controls

Room to improve

  • 🐛 Stability issues, crashes on some devices
  • 🔌 Compatibility problems with newer iOS versions
  • 📂 Preset management could be improved
  • 🔀 Lack of MIDI learn and sequencer features
  • 🖥️ UI scaling issues on larger iPad displays

Bugs and requests

iSEM Synthesizer

Reported bugs

5 issues
  • Preset loading issues
  • MIDI connectivity problems
  • Unexpected crashes when switching between presets
  • Envelopes causing clicks and pops in some patches
  • Unresponsive controls when used as an AUv3

Requested features

5 requests
  • Add MIDI program change support
  • Improve preset management and organization
  • Implement a global tuning option
  • Enhance MIDI mapping and automation capabilities
  • Provide more comprehensive AUv3 support

Zeeon synth

Reported bugs

4 issues
  • Preset settings not retained after app restart
  • Synth reverts to default settings when reopening Logic Pro project
  • Crashes and freezes on certain iOS 14+ devices
  • Inability to access in-app purchases from within the app

Requested features

5 requests
  • Add MIDI learn functionality
  • Implement a more robust preset management system
  • Include a built-in sequencer with save/load capabilities
  • Improve UI scaling and layout for larger iPad screens
  • Provide better integration with inter-app audio and Audiobus

In-app purchases

None

iSEM Synthesizer

No in-app purchases

3 purchases

Zeeon synth

One-time3
  • OI - Exploration Vol. 1$3.99
  • BB Z-Space$4.99
  • BB Synthwave$4.99

Questions

Is iSEM Synthesizer free?
iSEM Synthesizer costs $9.99, with no in-app purchases.
Is Zeeon synth free?
Zeeon synth costs $14.99, and also offers in-app purchases.
Which has better reviews, iSEM Synthesizer or Zeeon synth?
Zeeon synth is rated higher. iSEM Synthesizer averages 4.1 out of 5 from 60 ratings, while Zeeon synth averages 4.8 from 209 ratings.
Do iSEM Synthesizer or Zeeon synth have ads?
Neither iSEM Synthesizer nor Zeeon synth shows ads.
Which is updated more often, iSEM Synthesizer or Zeeon synth?
iSEM Synthesizer ships an update every 5 months, and Zeeon synth every 2 months. Most recently, iSEM Synthesizer was updated on October 23, 2026 and Zeeon synth on October 29, 2026.

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