Stellr vs GSDSP Quantum Delay
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Stellr
Create deep, ethereal ambiance with a pitch-shifter, dual delays, and reverb. Explore sonic possibilities with 15 presets, randomization, and parameter automation. Enhance your music with a new dimension of sound.
- Pitch shifter with fine-tuning or semitone snap
- Two independent delays for complex feedback
- LFO modulation and various reverb types
- Pre-gain and dry/wet level control
- Audio Unit Extension, Audiobus, Inter-App Audio support
- 15 built-in presets with import/export
- Realtime frequency spectrum visualizer
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Stellr is a pitch-shifter/delay/reverb sound processor aimed to recreate the classic shimmer effect. It makes deep ethereal ambiance on top of your sound, providing you with a wide variety of sonic possibilities. Add a new dimension to your music. The effect features 20 ready to use presets which can be shared between devices as well as randomize button for endless variations. When loaded as Audio Unit effect, all parameters can be automated via host app. Stellr main features: – Pitch shifter which can be fine-tuned or snapped to semitone – Two separate delays for creating a complex feedback effect – LFO modulation and different types of reverb – Set pre-gain and dry/wet levels – Audio Unit Extension support – 20 built-in presets – Low-pass and High-pass filters – Ability to save and randomize parameters – Import and export of user presets – Realtime frequency spectrum visualizer
GSDSP Quantum Delay
This app offers a vintage-inspired stereo delay effect with advanced modulation, flexible filtering, and precise timing controls. It allows users to sculpt unique echo textures, from warm analog sounds to complex, evolving soundscapes.
- Vintage-inspired stereo delay
- Deep modulation system
- Flexible filtering (LPF, HPF, BPF)
- Precise timing controls (BPM, ms)
- Switchable stereo/dual mono modes
- Advanced modulation sources (LFO, Random, Envelope)
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A vintage-inspired delay supercharged with deep modulation, flexible filtering, and creative timing that pushes echoes into new dimensions. Classic Delay, Reinvented Quantum Delay takes the charm of a vintage stereo delay and fuses it with our next-level modulation system. Switch between the warm character of Tape mode and the pristine clarity of Fade mode, lock to BPM (including 5-tuplets) or dial in precise times in milliseconds. Use the Fine control for subtle push-and-pull micro-timing — or modulate your delay lines in ways traditional delays could only dream of. Sculpted Echoes Shape your repeats with switchable lowpass, highpass, and bandpass filters placed directly in the feedback path. Add modulation to create evolving tones, gentle movement, or drifting, frequency-shifting echoes. From warm analog-style rolls to shimmering, swirling textures, it’s all there. Feedback with Precision Control your delay tail behavior using either traditional % feedback or our modern dB-per-second decay system — ideal for predictable, musical decay even when the feedback path becomes complex. Enable Crossfeed for classic ping-pong stereo bounce, or push into Over-Feedback to create dense, self-building echoes that drift toward infinity. Stereo or Dual Mono Every section of Quantum Delay — delay, filter, and feedback — can switch between stereo and dual mono modes. Create tight, controlled stereo images or break them apart for wide, offset, unpredictable spaces. Dual mono modulation unlocks complex stereo interplay and beautifully asymmetric echoes. Modulation Without Limits Quantum Delay integrates our advanced modulation system, letting you modulate nearly anything: delay time, filters, feedback parameters, stereo controls, and more. Use LFOs, Random Generators, 2D modulators, Envelope Followers, Macros, and even chaotic systems to push your echoes far beyond traditional delay behavior. Or use our parameter randomisation feature to explore the plugin’s sound at random. Quantum Delay is an AUv3 audio effect plugin compatible with Logic Pro, AUM, Cubasis, GarageBand and many more. A Desktop version is also available for Windows and macOS (VST3 / AU / AAX). More information here: https://gs-dsp.com/products
Screenshots
Verdict
The clearest difference is price: Stellr at $4.99 against GSDSP Quantum Delay's $14.99. GSDSP Quantum Delay's advantage is rating (4.8 vs 3.4) and review sentiment (100% vs 67%). On ratings volume, ads, in-app purchases and monetization model 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
Stellr costs $4.99 and GSDSP Quantum Delay $14.99 up front. Neither carries in-app purchases, so what you see is what you pay.
GSDSP Quantum Delay holds the better App Store score, 4.8 against 3.4. Both are backed by a comparable volume of ratings — 9 and 16 respectively. Written reviews point the same way: 67% of Stellr's written reviews are positive against 100% of GSDSP Quantum Delay's.
Stellr ships an update every 40 months, GSDSP Quantum Delay every 6 weeks. The most recent releases landed on October 19, 2026 and October 25, 2026 respectively.
| Parameter | Stellr | GSDSP Quantum Delay |
|---|---|---|
| Price | $4.99 — better | $14.99 |
| Rating | 3.4 (9 ratings) | 4.8 (16 ratings) — better |
| Positive reviews | 66.7% of reviews | 100.0% of reviews — better |
| Number of ratings | 9 | 16 — better |
| Update frequency | Every 40 months | Every 6 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 12.0 — better | 13.0 |
| Further details — not scored | ||
| Size | 26 MB | 94 MB |
| Age rating | 4+ | 4+ |
| Developer | BACKPULLVER SOFTWARE LTD OOD | Gustav Scholda |
Customer experience
Stellr
GSDSP Quantum Delay
In-app purchases
Stellr
No in-app purchases
GSDSP Quantum Delay
No in-app purchases









