TGX vs GSDSP Quantum Delay
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
TGX
This app recreates a legendary synthesizer's sound with an extensive 18GB library. It offers standalone and AUv3 compatibility, allowing users to access factory presets, raw waveforms, and drum kits for professional music production.
- Virtual sample library of Yamaha SY99/77
- 18GB lossless sound library
- Includes all factory presets and raw waveforms
- Standalone and AUv3 compatible
- Advanced FM Technology (AFM)
- High-quality A/D converters
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Released in 1991 this one is probably our second favorite synthesizer next to the EX5. The thing that made this synth amazing was it's AFM (Advanced FM Technology). Not only could it read the DX7 patches, but the enhanced AFM allowed for even better FM EPs with a ton of expression. The other thing you will recognize from this synth is it's incredible A/D converters which really make the synthesizer sound warm and phat. You can still hear the digital edge, but it's mixed with a warm analog tone that made all of the patches just sound professional and organic. Highlights: • Standalone and AUv3 Compatible • Yamaha SY99/77 Virtual Sample Library • 18GB Library (11GB Lossless on Disk) • Includes all 256 Factory Presets • Includes all RAW Waveforms • Includes all Drum Kits --------- The Ultimate Recreation of a Legendary Synth Classic: • Factory Presets - You get 128 Factory SY99 Presets and 128 Factory SY77 Factory Presets • Raw Waveforms - We give you access to the RAW Waveforms so that you can re-create some of your favorite patches. Our synthesis is powerful enough to get very close! • Capturing Nostalgia - Most of our presets use the exact wave layers as the hardware, which allows you to tweak to your liking. When needed, we used the sampled version. • Taking it to Another Level - Because our synthesizer is a bit more powerful than the hardware, you can now create presets that rival the hardware. • We sampled the factory presets with the effects on to capture the "exact" nostalgia of the hardware. --------- Standalone vs Pure Synth® Expansion - Standalone version has the black skeuomorphic interface - Expansion Unlocks inside of Pure Synth® FREE Player (https://apps.apple.com/us/app/pure-synth-platinum/id1459688500#see-all/in-app-purchases) - The Expansion includes the iPhone Version and the standalone does not - The Expansion includes the dynamic modulation from Pure Synth® - The Expansion allows you to mix and match libraries with one single interface ------- Sample Size and Space ▪ 18GB RAW Sound Library Before Lossless Compression ▪ 11GB Actual Size on Device After Lossless Compression ▪ 2GB RAM or Higher Required ***Lossless compression is a way to compress audio files without losing quality. ---------------- Device Specifications: ▪ 2GHz ARM Processor Recommended - iPad Pro 12.9 and 9.7 in, iPad 5th Gen, iPad Pro 12.9 in. (Gen 2), iPad Pro 10.5 in., iPad 6th Gen, iPad Pro 11 in., iPad Pro 12.9 in. (Gen 3), iPad Air (Gen 3) ▪ For External Sample Streaming, we only recommend Fast External SSD Drives (Not USB Thumb Drives) ---------------- External Drive Storage Our app is one of the first apps ever to offer external Drive Storage. In order to save space, you can store all of the samples on an external SSD and it will stream and read the sounds in real-time.
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: GSDSP Quantum Delay at $14.99 against TGX's $19.99. GSDSP Quantum Delay also leads on rating (4.8 vs 4.5) and ratings volume (17 vs 4). On in-app purchases, monetization model and iOS requirement 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
TGX 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 4.5. Both are backed by a comparable volume of ratings — 4 and 17 respectively.
| Parameter | TGX | GSDSP Quantum Delay |
|---|---|---|
| Price | $19.99 | $14.99 — better |
| Rating | 4.5 (4 ratings) | 4.8 (17 ratings) — better |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | 4 | 17 — better |
| Update frequency | — | Every 5 weeks |
| Ads | — | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | — | iPhone, iPad, iPod — better |
| Requires iOS | 11.0 — better | 12.0 |
| Further details — not scored | ||
| Size | 317 MB | 94 MB |
| Age rating | 4+ | 4+ |
| Developer | MIDIculous LLC | Gustav Scholda |
In-app purchases
TGX
No in-app purchases
GSDSP Quantum Delay
No in-app purchases









