Qithesizer vs GSDSP Quantum Delay
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Qithesizer
This advanced music synthesizer combines virtual analog, wavetable, and physical modeling sound engines. It offers extensive modulation capabilities, a built-in sequencer, and on-screen keyboard for creating complex sounds.
- Multiple sound engines (virtual analog, wavetable, physical modeling)
- Extensive modulation sources and destinations
- Full MIDI mapping
- 16-step sequencer with pattern editor
- Waveform and dynamic visualizations
- On-screen keyboard
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Meet Qithesizer, a powerful multi-engine hybrid software synthesizer. Designed with wind controller in mind, it combines virtual analog, wavetable, and physical modeling in one. 【Features】 ∙ Multiple sound engines: basic waveforms, hundreds of digital waveforms, multiple physical models ∙ 11 modulation sources, 27 modulation destinations ∙ Full midi mapping ∙ 16-step sequencer with powerful pattern editor, save patterns by preset ∙ Waveform and dynamic visualizations ∙ Full-size, on-screen keyboard Our site: www.robkoo.com Facebook Page: @RobkooMusic Twitter: @Robkoo_Music Feedback: cuimingwei@robkoo.com
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 rating: GSDSP Quantum Delay at 4.8 against Qithesizer's 4.1. GSDSP Quantum Delay also leads on review sentiment (100% vs 77%) and iOS requirement (12.0 vs 15.0). Qithesizer's advantage is update cadence (fortnightly vs every 5 weeks) and price ($12.99 vs $14.99). 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
Qithesizer costs $12.99 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 4.1. Both are backed by a comparable volume of ratings — 11 and 17 respectively. Written reviews point the same way: 77% of Qithesizer's written reviews are positive against 100% of GSDSP Quantum Delay's.
Qithesizer ships an update fortnightly, GSDSP Quantum Delay every 5 weeks. Both last shipped on September 22, 2026.
| Parameter | Qithesizer | GSDSP Quantum Delay |
|---|---|---|
| Price | $12.99 — better | $14.99 |
| Rating | 4.1 (11 ratings) | 4.8 (17 ratings) — better |
| Positive reviews | 76.9% of reviews | 100.0% of reviews — better |
| Number of ratings | 11 | 17 — better |
| Update frequency | Fortnightly — better | Every 5 weeks |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.0 | 12.0 — better |
| Further details — not scored | ||
| Size | 29 MB | 94 MB |
| Age rating | 4+ | 4+ |
| Developer | Robkoo Information & Technologies Co., Ltd. | Gustav Scholda |
Customer experience
Qithesizer
GSDSP Quantum Delay
In-app purchases
Qithesizer
No in-app purchases
GSDSP Quantum Delay
No in-app purchases









