amoenus externus vs PX1 FM Synth
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
amoenus externus
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amoenus externus transforms your headphone listening into a natural speaker experience. Using a carefully tuned arrangement of 9 ultra-short delays, it recreates the acoustic perception of a classic stereo speaker triangle — placing the sound naturally in front of you, slightly outside your head, rather than inside it. No artificial reverb. No coloration. Just a more natural, fatigue-free headphone sound. Compatible with foobar2000 (v2.25+), AUM, GarageBand, and all AUv3-compatible hosts on iOS.
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.
Screenshots
Verdict
The clearest difference is price: amoenus externus at $2.99 against PX1 FM Synth's $7.99. amoenus externus also leads on iOS requirement (12.0 vs 17.6). On update cadence, ads, in-app purchases 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
amoenus externus costs $2.99 and PX1 FM Synth $7.99 up front. Neither carries in-app purchases, so what you see is what you pay.
amoenus externus ships an update fortnightly, PX1 FM Synth every 2 weeks. The most recent releases landed on October 30, 2026 and November 5, 2026 respectively.
| Parameter | amoenus externus | PX1 FM Synth |
|---|---|---|
| Price | $2.99 — better | $7.99 |
| Rating | — | 5.0 (2 ratings) — better |
| Number of ratings | — | 2 — better |
| Update frequency | Fortnightly — better | Every 2 weeks |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | — | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Mac |
| Requires iOS | 12.0 — better | 17.6 |
| Further details — not scored | ||
| Size | 8 MB | 121 MB |
| Age rating | 4+ | 4+ |
| Developer | Erich Meier | Peter Sjogren |
In-app purchases
amoenus externus
No in-app purchases
PX1 FM Synth
No in-app purchases









