sumFX vs isxynth
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
sumFX
This app is a versatile audio effects processor for musicians. It offers a modular design with multiple high-quality FX modules and customizable slots, allowing for quick creation of unique sounds. Focus on your music with intuitive controls and visual feedback.
- Modular multi-FX processor
- 8 high-quality FX modules
- 8 FX slots with Wet/Dry control
- 2 LFOs per slot
- 50+ cross-platform presets
- Pre/post waveform view
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sumFX is a modular multi-FX processor for Mac/PC and iOS. Designed with simplicity in mind, to help keep you focused on the music and the sum of your efforts. Packed with 8 high quality FX modules and an available 8 slots, each loaded with Wet/Dry control, Global Wet/Dry, and 2 LFOs per slot, creating new unique sounds is quick and easy. 50+ cross-platform slot & chain presets are included to get you to any sound you need quickly and we’ve packed in an easy to use pre/post waveform view to help keep you focused on the result of your FX. Modules: -syncDynamics - Multimode dynamic FX with BPM sync attack/release (Noise Gate, Expander, Compressor, Limiter) -stereoFilter - Stereo filter with link or individual channel controls (LPF12, HPF12, BPF12, LPF24, HPF24, BPF24, Notch, & Formant options). -variMod - Multimode modulation FX with stereo offset (Chorus, Flanger, Vibrato, Phaser, Tremolo, & Auto Pan) -EQuator - Full high quality EQ module (3 Parametric Bands, High/Low Shelf, & HPF/LPF). -frostReverb - Multi-Mode (Original, Plate, Spring, Room) Stereo Reverb. -bucketDelay - Stereo Analog Style Delay with individual channel control. -variPitch - Stereo Pitch Shifter with 3X Modes (Doubler, Harmonizer, & Full Control) -powerPhase - Multimode Saturation, Utility Gain In/Out, Mono Maker, Channel msDelay, & Phase inverter.
isxynth
This music effect plugin allows spectral cross synthesis and morphing between two input signals. It separates noise and tone components, offering controls for blending, freezing, and time-based delays. Gestures on controls can be recorded and played back for dynamic sound shaping.
- Spectral cross synthesis
- Morphing between two input signals
- Noise and tone component blending
- Freeze control for spectral blurring
- 3-second delay lines per input
- Gesture recording and playback
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isxysnth is spectral cross synthesis / morphing plugin it gets two input signals, splits each one into 2 parts containing noise and tone components and then allows morphing between all these elements. Freeze control allows spectral blurring-like effect for both input signals, two 3 second delay lines allow selection of different signal in time and also provide "freeze" effect you can process left and right channels on stereo source or use this effect as multi-input AUv3 - in that case it will use 2 stereo inputs. Standalone mode currently works only in "mono" mode - three XY controls set balance between tone and noise components, amount of freeze and set up morphing - both inputs have 3-second delay line; freeze button ("*") toggles off recording. - gestures on all the main controls (3 xy pads and two sliders) can be recorded and played back when appropriate button with ">" label is toggled on - in current version standalone app supports only mono (L + R as inputs I and II) processing
Screenshots
Verdict
The clearest difference is review sentiment: isxynth at 100% against sumFX's 55%. isxynth also leads on price ($7.99 vs $9.99). sumFX's advantage is rating (4.4 vs 3.7) and update cadence (every 6 months vs every 34 months). On ads, in-app purchases, monetization model 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
sumFX costs $9.99 and isxynth $7.99 up front. Neither carries in-app purchases, so what you see is what you pay.
sumFX holds the better App Store score, 4.4 against 3.7. Both are backed by a comparable volume of ratings — 12 and 3 respectively. Written reviews complicate that: 55% of sumFX's written reviews are positive against 100% of isxynth's, so the app with the better star average is not the one people write more warmly about.
sumFX ships an update every 6 months, isxynth every 34 months. The most recent releases landed on September 7, 2026 and September 24, 2026 respectively.
| Parameter | sumFX | isxynth |
|---|---|---|
| Price | $9.99 | $7.99 — better |
| Rating | 4.4 (12 ratings) — better | 3.7 (3 ratings) |
| Positive reviews | 54.5% of reviews | 100.0% of reviews — better |
| Number of ratings | 12 — better | 3 |
| Update frequency | Every 6 months — better | Every 34 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 12.0 | 11.0 — better |
| Further details — not scored | ||
| Size | 44 MB | 8 MB |
| Age rating | 4+ | 4+ |
| Developer | OSC Audio | Alexey Nadzharov |
Customer experience
sumFX
isxynth
In-app purchases
sumFX
No in-app purchases
isxynth
No in-app purchases
