GSiRotary vs GSDSP Quantum Delay
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
GSiRotary
This AUv3 plugin emulates the iconic sound of Leslie rotary speakers for iPad. It offers detailed control over speeds, ramp times, balance, and microphone placement, along with built-in tube overdrive and reverb. Achieve authentic vintage speaker tones with low CPU impact.
- AUv3 plugin for compatible host apps
- Emulates Leslie tube models (122, 147, etc.)
- Adjustable speeds for upper and lower speakers
- Adjustable ramp up and down times
- Adjustable balance between speakers
- Adjustable microphone position
- Built-in tube overdrive and digital reverb
Read full descriptionHide full description
Please note: this is an AUv3 plugin that can be used with compatible host Apps. GSiRotary for iPad is the portable version of the very same Rotary Speaker algorithm found in the software GSi VB3-II and in the hardware keyboards Crumar Mojo (Classic and Suitcase), Mojo Desktop, Mojo 61 as well as in the GSi Gemini. As a Rotary Speaker effect it reproduces the effect and the tonal characteristics of the famous Leslie speakers, specifically the tube models 122, 147, 142, 145 and 251. It's not based on one single model, because there's actually very little difference between these models. Changing some parameters can make it sound more like a model or more like another one, letting alone the fact that even two or more apparently identical Leslies of the same model would not sound really identical after more than 60 years. GSiRotary takes this into account and offers a parameter set that can help us reach the rotary speaker sound we have in mind. Main features: - very low impact on CPU and RAM - adjustable speeds for upper and lower speakers separately - adjustable ramp up and down times - adjustable balance between upper and lower - adjustable microphone position (angle and distance) - built-in tube overdrive and digital reverb - comes as AUv3 plugin - supports background audio
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)
Read full descriptionHide full description
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 GSiRotary's 3.7. GSDSP Quantum Delay also leads on update cadence (every 6 weeks vs every 17 months) and price ($14.99 vs $19.99). 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
GSiRotary costs $19.99 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 3.7. That said, the two scores are not equally well evidenced: GSDSP Quantum Delay has 17 ratings behind it against 3, so its average is the more settled of the two. Written reviews point the same way: 80% of GSiRotary's written reviews are positive against 100% of GSDSP Quantum Delay's.
GSiRotary ships an update every 17 months, GSDSP Quantum Delay every 6 weeks. The most recent releases landed on October 24, 2026 and October 27, 2026 respectively.
| Parameter | GSiRotary | GSDSP Quantum Delay |
|---|---|---|
| Price | $19.99 | $14.99 — better |
| Rating | 3.7 (3 ratings) | 4.8 (17 ratings) — better |
| Positive reviews | 80.0% of reviews | 100.0% of reviews — better |
| Number of ratings | 3 | 17 — better |
| Update frequency | Every 17 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 | 12 MB | 94 MB |
| Age rating | 4+ | 4+ |
| Developer | Genuine Soundware | Gustav Scholda |
Customer experience
GSiRotary
GSDSP Quantum Delay
In-app purchases
GSiRotary
No in-app purchases
GSDSP Quantum Delay
No in-app purchases
Questions
Is GSiRotary free?
Is GSDSP Quantum Delay free?
Which has better reviews, GSiRotary or GSDSP Quantum Delay?
Do GSiRotary or GSDSP Quantum Delay have ads?
Which is updated more often, GSiRotary or GSDSP Quantum Delay?
Other comparisons















