Comparison

Poseidon Synth vs OPL AUv3 FM Synth

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

Head to head
About

Poseidon Synth

Explore vast sonic landscapes with this advanced synthesizer. It combines analog synthesis with spectral modeling for unique sound design, offering powerful filters, spatialization, and a vast library of presets and sound models.

Highlights
  • Spectral model oscillator
  • F-Domain Filter with variable slope
  • Spatializer for stereo movement
  • Extensive sound browser
  • Arpeggiator with programmable sequences
  • Built-in effects suite
Read full description

Poseidon Synth - The Ocean of Sound For all creatures in the ocean of sound - Sonic textures from other worlds, Analog signature sounds,  Cut-through-the-mix leads and silkily smooth pads: Poseidon sets a new standard for sound design and ease of use. All of this was made possible through a combination of the familiar, conceptual simplicity of the analog synthesis and our frequency domain based Spectral modelling synthesis technology. Spectral model oscillator Select a basic sound model from over hundred delivered with Poseidon. The basic sound model determines the sound characteristic you want to start: taking a artificial model like “Sawtooth” gives you analog style sounds. Use complex models from analyzed samples for earth shaking ambients and evolving pads. Model parameters High level controls allow for changing the spectral shape, the harmonicity and balances the level of residual noise and spectral amount of the oscillator model. F-Domain Filter The newly developed F-Domain filter allow for drastic changes in the resulting sound spectrum. Five filter types including lowpass/highpass characteristic can be used to shape the sound. They have the usual controls like cutoff but also very unusual ones like a variable slope ranging from 0 dB to 72 dB / Octave and independent controls for resonance and bandwidth! This kind of controls are only possible in the context of our F-Domain synthesis technology. This results in an extremely clear filter sound with breathtaking fast modulation possibilities.

The filter type “Inverse” interprets the sound model as a "Source" and a resonant body "Filter". The cutoff parameter shifts the filterbase - this is the equivalent to making the instrument body smaller or bigger. Spatializer This simple control gives your sound a distinctive moving distribution in the stereo panorama. Every atomic sound particle has it´s own path through the space ! Sound browser The sound browser in Poseidon gives you a fast selection of sounds based on category and timbre. Spectral modelling synthesis • Harmonic/Inharmonic/Noise sound models • 512 oscillators per voice • 300 Sound models / 600 factory presets Unique sound control • Pitch modulation / Harmonicity control • Time machine • Timbre control • Frequency Domain Filter • Spatializer Arpeggiator • Uses programmable sequences with up to 32 steps.  • Can trigger single notes and chords. • Unique randomiser generates Arpeggios with 100% usability. • 32 Arpeggios included, unlimited user arpeggios possible. • For each step you can program tie, accent, transposition and note order Effects • Chorus • Phaser • Flanger • Distortion (aliasing free!) • Equalizer • Echo/Delay • Reverb Global • Audiobus 3 compatible (Input slot) • Audio Unit AUv3 • Inter-app audio compatible (Instrument/Generator) • CoreMIDI / Virtual MIDI / Tempo Sync / MIDI Learn • Audio recorder with Metronome. • Audio pasteboard / File sharing. • Ableton Link support • Bluetooth audio A2DP

About

OPL AUv3 FM Synth

Emulates the iconic Yamaha OPL2 chip for classic game soundtracks and electronic music. Offers FM and additive synthesis with over 2000 presets and 16x oversampling for clear audio. Requires a MIDI keyboard for standalone use.

Highlights
  • OPL2 chip emulation
  • FM and additive synthesis
  • Distinctive percussion mode
  • 16x oversampling
  • Over 2000 presets
  • Standalone MIDI keyboard support
Read full description

The Yamaha OPL chips, introduced in 1985, shaped the sound of 80s and 90s video game soundtracks. discoDSP OPL emulates their FM and additive synthesis, including the distinctive percussion mode. With up to 16x oversampling for crystal-clear sound and over 2000 included presets, discoDSP OPL is ideal for classic game soundtracks, electronic music, or crafting unique sounds. Play it with the built-in on-screen keyboard on iPad, a MIDI controller, or your DAW. On iPhone, connect a MIDI keyboard or run it as a plugin. CORE FEATURES • YMF262 (OPL3) FM engine with all eight waveforms per operator. • Percussion mode with bass drum, snare, tom, cymbal, and hi-hat. • Over 2000 SBI instruments, organised by category. • Two operators with wave, multiplier, envelope, and attenuation. • Selectable oversampling from 1x to 16x, with a separate bounce setting. • Key-tracking stereo panning that places notes across the field by pitch. • AN1x-style unison with 32-step detune and stereo spread. • MPE support with pressure and slide routable to synth parameters. • On-screen keyboard with pitch and modulation wheels (iPad, standalone). • Analog modeled wave shaper on the carrier. • SBI instrument import and export through the Files app. • Bluetooth MIDI device discovery. • AUv3 plugin for GarageBand, AUM, Cubasis, BeatMaker, and Drambo. THE OPL SOUND Two-operator FM is the sound of Adlib and Sound Blaster era games. Each voice pairs a modulator and a carrier, each with its own waveform, frequency multiplier, envelope, and attenuation. Route them in FM for the metallic, bell-like timbres the chip is known for, or in additive to stack the two operators as independent tones. Feedback on the modulator pushes the tone from clean to gritty, and all eight OPL3 waveforms are available on every operator: sine, half sine, absolute sine, quarter sine, alternating sine, camel sine, square, and logarithmic sawtooth. They are the chip's own, not approximations. PERCUSSION MODE The rhythm section repurposes the last channels into five dedicated drum voices: bass drum, snare, tom, cymbal, and hi-hat. It is how the chip made drums without samples, and it is included here in full. INSTRUMENTS Over 2000 SBI instruments are included, sorted into categories: bass, drum, FX, guitar, keys, and more. Load one from the menu, step through them with the previous and next buttons, or import your own SBI files from the Files app. Anything you edit can be exported back out as SBI. OVERSAMPLING The chip is emulated at up to 16 times the host sample rate, which stops the FM sidebands folding back into the audio band as aliasing. Playback and offline bounces have separate settings, so you can run a lighter factor while playing and render at the highest quality. ON-SCREEN KEYBOARD The standalone app on iPad includes a keyboard with pitch and modulation wheels, so you can play without any external hardware. The mod wheel drives a vibrato LFO with continuous depth, going well beyond the original chip's fixed two-position vibrato. Hide the keyboard from the settings menu when you would rather give the panel the whole screen. STANDALONE OR AUV3 Load OPL inside GarageBand, AUM, Cubasis, BeatMaker, Drambo, or any AUv3 host, with settings saved in your project. Or run it standalone with a MIDI controller, over Bluetooth MIDI, or with the on-screen keyboard.

Screenshots

OPL AUv3 FM Synth1 screens

Verdict

The call

The clearest difference is rating: OPL AUv3 FM Synth at 4.4 against Poseidon Synth's 4.0. OPL AUv3 FM Synth also leads on review sentiment (73% vs 59%) and device support (3 vs 1). Poseidon Synth's advantage is price ($7.99 vs $9.99) and iOS requirement (12.0 vs 15.0). On ratings volume, update cadence, ads and in-app purchases 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

Poseidon Synth costs $7.99 and OPL AUv3 FM Synth $9.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

OPL AUv3 FM Synth holds the better App Store score, 4.4 against 4.0. Both are backed by a comparable volume of ratings — 33 and 24 respectively. Written reviews point the same way: 59% of Poseidon Synth's written reviews are positive against 73% of OPL AUv3 FM Synth's.

UpkeepUpdate frequency

Poseidon Synth ships an update every 4 months, OPL AUv3 FM Synth every 3 months. The most recent releases landed on August 4, 2026 and September 20, 2026 respectively.

Scorecard5 real differences · 5 level
Poseidon Synth versus OPL AUv3 FM Synth: the parameters behind the verdict, then further details
ParameterPoseidon SynthOPL AUv3 FM Synth
Price$7.99 — better$9.99
Rating4.0 (33 ratings)4.4 (24 ratings) — better
Positive reviews58.8% of reviews72.7% of reviews — better
Number of ratings33 — better24
Update frequencyEvery 4 monthsEvery 3 months — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
DevicesiPadiPhone, iPad, iPod — better
Requires iOS12.0 — better15.0
Further details — not scored
Size328 MB35 MB
Age rating4+4+
DeveloperHarry GohsDiscoDSP LLC

Customer experience

Poseidon Synth

All ratings33 ratings
Positive72.7%
Neutral12.1%
Negative15.2%
Written reviews51 reviews
Positive58.8%
Neutral15.7%
Negative25.5%

OPL AUv3 FM Synth

All ratings24 ratings
Positive87.5%
Neutral0.0%
Negative12.5%
Written reviews11 reviews
Positive72.7%
Neutral9.1%
Negative18.2%

In-app purchases

None

Poseidon Synth

No in-app purchases

None

OPL AUv3 FM Synth

No in-app purchases

Questions

Is Poseidon Synth free?
Poseidon Synth costs $7.99, with no in-app purchases.
Is OPL AUv3 FM Synth free?
OPL AUv3 FM Synth costs $9.99, with no in-app purchases.
Which has better reviews, Poseidon Synth or OPL AUv3 FM Synth?
OPL AUv3 FM Synth is rated higher. Poseidon Synth averages 4.0 out of 5 from 33 ratings, while OPL AUv3 FM Synth averages 4.4 from 24 ratings.
Do Poseidon Synth or OPL AUv3 FM Synth have ads?
Neither Poseidon Synth nor OPL AUv3 FM Synth shows ads.
Which is updated more often, Poseidon Synth or OPL AUv3 FM Synth?
Poseidon Synth ships an update every 4 months, and OPL AUv3 FM Synth every 3 months. Most recently, Poseidon Synth was updated on August 4, 2026 and OPL AUv3 FM Synth on September 20, 2026.

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