CC Harp vs GSDSP Quantum Delay
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
CC Harp
This app simulates a 10-hole diatonic harmonica, offering expressive sound capabilities with intuitive touch controls. It allows for pitch bends, tremolo effects, and even chord play. Additional features like multiple keys, a tuner, and various sound effects are available through in-app purchases.
- 10-hole diatonic harmonica simulation
- Independent and adjacent sound touches
- Smart chord play with two fingers
- Pitch bends and sound muffling
- Adjustable tremolo effect
- Left-handed screen reversal
- Dark mode support
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10-hole diatonic harmonica (sometimes called "blues harp") is a small but powerful instrument with great expressiveness. CC Harp is a musical instrument application designed to take full advantage of the deep characteristics of harmonica, and is also pursued for rich usability in live. Since it uses a synthetic sound source method, it can handle various sounds with a small footprint of memory. Features - Interface is modeled after the harmonica holes. - Make sound with up to two independent touches. - Make adjacent sounds with a single touch. - Easy chord play with two finger by smart chord feature. - Various splitting performances with 2 fingers touch. - Pitch bends based on actual harmonicas are possible. - You can muffle the sound just as you would with a harmonica. - You can apply a tremolo effect with variable speed. - The screen can be reversed for left-handed people. - Change the screen color to your liking. - Supports dark mode. - A detailed user guide is built-in and ready to use. The following features are added with in-app purchases: - All 12 harmonica keys are available. - Built-in pitch tuner. - Lower the pitch by one octave is available. - Various harmonica tunings are built-in. - Reverb effect is available. - Adjustable airy noise that is unique with harmonica playing. - Touch vibrato with adjustable sensitivity. - Volume expression can be made by tilting the device. - Accurate pitch bend is possible. - You can make bends that are impossible with a real harmonica. - Slide operation like a chromatic harmonica is possible. - Note name and interval display that is convenient for playing. - Concise banner shows the settings at a glance. - Preset settings like a pocket with several different harmonica in it. - Several built-in synthetic sounds including harmonica-like tones, flute, stringed, etc. - Simple sound synthesizer where you can create new sound. - You can Play-along with a song in your iPod library. - Sound data can be exported and imported via the device clipboard. - You can design your own harmonica tuning and import it. You can try out extra features for two weeks by purchasing the "Free Trial" in-app purchases. Any interworking functions such as Inter-App Audio, AUv3, and MIDI, and function for recording and playback the performance are currently not supported. Detailed features and usage of CC Harp are explained in the User Guide on the web below. https://chord-city.com/cc_harp/user_guide/ If you have any questions or concerns, feel free to contact us at support@chord-city.comIf you have any questions or concerns, feel free to contact us at support@chord-city.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 price: CC Harp at Free against GSDSP Quantum Delay's $14.99. CC Harp also leads on rating (5.0 vs 4.8). GSDSP Quantum Delay's advantage is in-app purchases (none vs 2) and update cadence (every 5 weeks vs every 4 months). On ads, device support 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
CC Harp is free to download; GSDSP Quantum Delay costs $14.99 up front. CC Harp sells 2 one-off in-app purchases. GSDSP Quantum Delay asks for nothing beyond the download.
CC Harp holds the better App Store score, 5.0 against 4.8. That said, the two scores are not equally well evidenced: GSDSP Quantum Delay has 17 ratings behind it against 1, so its average is the more settled of the two.
CC Harp ships an update every 4 months, GSDSP Quantum Delay every 5 weeks. The most recent releases landed on June 22, 2026 and September 22, 2026 respectively.
| Parameter | CC Harp | GSDSP Quantum Delay |
|---|---|---|
| Price | Free — better | $14.99 |
| Rating | 5.0 (1 ratings) — better | 4.8 (17 ratings) |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | 1 | 17 — better |
| Update frequency | Every 4 months | Every 5 weeks — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases — better | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 12.0 | 12.0 |
| Further details — not scored | ||
| Size | 17 MB | 94 MB |
| Age rating | 4+ | 4+ |
| Developer | Kazuo Kamata | Gustav Scholda |
Customer experience
CC Harp
GSDSP Quantum Delay
In-app purchases
CC Harp
- Extra Features TrialFree
- Extra Features$3.99
GSDSP Quantum Delay
No in-app purchases









