PX1 FM Synth vs PolyQuad
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
PX1 FM Synth
Create rich, wide stereo sounds with a dual-engine FM synthesizer. Explore classic 1980s digital synth tones, from electric pianos to metallic bells, with extensive operator and envelope controls. It functions as a standalone app or an AUv3 plugin for music production.
- Dual independent 6-operator FM engines
- 32 classic FM algorithms
- Per-operator envelopes and pan
- Five macro knobs for sound shaping
- Built-in reverb
- AUv3 plugin support
- Random patch generator
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PX1 is a dual-engine FM synthesizer inspired by the classic 6-operator digital synths of the 1980s. Each engine features six operators, 32 algorithms, and full envelope control — giving you everything from glassy electric pianos and punchy basses to evolving pads and metallic bells. What makes PX1 special is the dual-engine architecture. Two completely independent FM voices run side by side. Copy one engine to the other, make subtle changes, then use the Spread control to place them across the stereo field. The result is a lush, wide sound that a single FM engine simply cannot produce. FEATURES • Two independent 6-operator FM engines • 32 classic FM algorithms • Per-operator envelopes (4 rates + 4 levels) • Per-operator pan for detailed stereo placement • Five macro knobs — Brightness, Touch, Attack, Decay, Spread • Copy/Paste between engines for instant layering • Random patch generator exploring the classic FM sound palette • Built-in reverb (Size, Damp, Amount) • Mono, Legato, and Portamento modes • LFO with triangle, saw, square, and random waveforms • Pitch bend range and transpose controls • Key velocity sensitivity per operator • Keyboard rate scaling and level scaling • Operator Key Sync on/off for consistent or organic attacks AUv3 PLUGIN PX1 works as a standalone instrument and as an Audio Unit v3 plugin. Load it directly inside GarageBand, Logic Pro, AUM, Cubasis, or any AUv3-compatible host. Full parameter automation is supported — record knob movements in your DAW and play them back. DESIGNED FOR MUSICIANS The interface stays close to the original FM programming model that experienced synthesists know, while macro controls make it approachable for anyone. Turn one knob and shape the entire sound; dive into individual operators when you want surgical control. LISTEN TO EXAMPLES Hear PX1 in action — sound demos are available at: https://soundcloud.com/peter-sj-gren/sets/px1-demo Requires no in-app purchases. No subscriptions. No ads. No tracking.
PolyQuad
Create complex analog-style synthesizer sounds using four independent voices. Design each voice with its own oscillator, filter, and envelopes, then combine them in various modes for massive layered textures, polyphonic chords, or unique stereo arrangements. Explore a vast library of presets or build your own from scratch.
- Four independent analog-style voices
- Multiple oscillator and filter types per voice
- Dual envelope generators per voice
- Three voice combination modes (UNI, POLY, 2x2)
- Extensive LFO modulation capabilities
- Integrated effects unit (reverb, delay, chorus, phaser, drive)
- 160 factory presets and user preset management
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PolyQuad is one synthesizer built from four complete voices — and the instrument is what they make together. Each of the four channels is a full analog-style voice: its own oscillator, its own resonant filter, its own envelopes, its own amplifier, its own place in the stereo field. Design each channel for a role — a sub, a body, a sparkle, a slow swell — then play them as one. Three voice modes decide how they combine. UNI stacks all four on every note for one massive layered sound. POLY spreads chords across the channels, so every note of a chord lands on its own instrument. 2×2 plays note pairs on matched couples. Add glide, retrigger control and detune spread on top. THE CHANNELS - Four oscillators: triangle, sawtooth, pulse with PWM, sine — per channel, with octave and fine tune - Four resonant filters with envelope amount and FM depth per channel - Two envelopes per channel (filter and amp), each with three time ranges from snappy to minutes-long - Per-channel VCA with velocity amount and curve, level, pan, AUX send, solo and mute - Per-channel oscilloscope displays, and keys that light up with the voice that took them MOTION - Four LFOs with five shapes, routed to pitch, pulse width, filter FM, resonance, amplitude, pan or send - Each channel decides how much modulation to accept — one LFO can wobble one channel and leave another still - One effect unit — reverb, delay, chorus, phaser, drive — fed by per-channel AUX sends with a master return PRESETS - 160 factory presets in eight categories: Pads, Keys, Strings, Bass, Lead, Drone, Texture, Percussion - Every preset uses the four channels as four different instruments — layered stacks, rotating timbres, per-drum kits - Channel presets: capture one channel's design and load it into any channel of any patch - Your presets are plain JSON files in the Files app — back them up, share them, drop new ones in IN THE STUDIO - AUv3 instrument for AUM, Drambo, Logic Pro, GarageBand and other hosts - MIDI 2.0 with 16-bit velocity; MIDI 1.0 hosts are translated automatically - Every knob on the panel is a host parameter — full automation and session recall - Standalone app with keyboard, so it plays on its own too No account, no ads, no tracking, no network. Your sounds stay on your device.
Screenshots
Verdict
The clearest difference is price: PolyQuad at $6.99 against PX1 FM Synth's $7.99. On rating, 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
PX1 FM Synth costs $7.99 and PolyQuad $6.99 up front. Neither carries in-app purchases, so what you see is what you pay.
On the App Store both sit at effectively the same score — 5.0 for PX1 FM Synth against 5.0 for PolyQuad. Both are backed by a comparable volume of ratings — 2 and 3 respectively.
Both ship on a similar rhythm, roughly every 2 weeks. The most recent releases landed on October 19, 2026 and October 18, 2026 respectively.
| Parameter | PX1 FM Synth | PolyQuad |
|---|---|---|
| Price | $7.99 | $6.99 — better |
| Rating | 5.0 (2 ratings) | 5.0 (3 ratings) |
| Number of ratings | 2 | 3 — better |
| Update frequency | Every 2 weeks | Every 2 weeks |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, Mac — better | iPhone, iPad |
| Requires iOS | 17.6 | 17.0 — better |
| Further details — not scored | ||
| Size | 121 MB | 4 MB |
| Age rating | 4+ | 4+ |
| Developer | Peter Sjogren | LASZLO DOBROVOLSZKI |
Customer experience
PX1 FM Synth
PolyQuad
In-app purchases
PX1 FM Synth
No in-app purchases
PolyQuad
No in-app purchases









