Comparison

VariSpeed vs GSDSP Quantum Delay

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

VariSpeed

This app simulates a classic tape echo machine, replicating the functionality of a specific vintage hardware unit. It allows for variable delay times by altering the speed of the tape mechanism.

Highlights
  • Classic tape echo simulation
  • Variable delay time
  • AUv3 plugin compatibility
  • Replicates vintage hardware
Read full description

Please note: this is an AUv3 plugin that can be used with compatible host Apps. GSi VariSpeed is a simulation of the WEM Copicat IC-400 Belt Drive VariSpeed model, the first tape echo machine made by WEM with a DC capstan motor capable of changing speed, thus varying the delay time. GSi VariSpeed replicates the hardware instrument “as is” with all its pros and cons, without any additional feature. This can be considered as the second chapter of a tribute to the genius of Mr. Charlie Watkins that GSi began back in 2008 with the release of the freeware "WatKat", which was a simulation of the "Custom Copicat".

About

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.

Highlights
  • 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)
Features
Read 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

GSDSP Quantum Delay3 screens

Verdict

The call

The clearest difference is update cadence: GSDSP Quantum Delay at every 5 weeks against VariSpeed's every 41 months. GSDSP Quantum Delay also leads on device support (3 vs 1). VariSpeed's advantage is price ($11.99 vs $14.99). On rating, review sentiment, ratings volume and ads 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

CostPrice · In-app purchases · Ads · Monetization

VariSpeed costs $11.99 and GSDSP Quantum Delay $14.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.9 for VariSpeed against 4.8 for GSDSP Quantum Delay. Both are backed by a comparable volume of ratings — 8 and 17 respectively. Written reviews split almost evenly too, at 100% and 100% positive.

UpkeepUpdate frequency

VariSpeed ships an update every 41 months, GSDSP Quantum Delay every 5 weeks. The most recent releases landed on September 10, 2026 and September 22, 2026 respectively.

Scorecard3 real differences · 7 level
VariSpeed versus GSDSP Quantum Delay: the parameters behind the verdict, then further details
ParameterVariSpeedGSDSP Quantum Delay
Price$11.99 — better$14.99
Rating4.9 (8 ratings) — better4.8 (17 ratings)
Positive reviews100.0% of reviews100.0% of reviews
Number of ratings817 — better
Update frequencyEvery 41 monthsEvery 5 weeks — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
DevicesiPadiPhone, iPad, iPod — better
Requires iOS12.012.0
Further details — not scored
Size11 MB94 MB
Age rating4+4+
DeveloperGenuine SoundwareGustav Scholda

Customer experience

VariSpeed

All ratings8 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

GSDSP Quantum Delay

All ratings17 ratings
Positive94.1%
Neutral0.0%
Negative5.9%
Written reviews4 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

VariSpeed

No in-app purchases

None

GSDSP Quantum Delay

No in-app purchases

Questions

Is VariSpeed free?
VariSpeed costs $11.99, with no in-app purchases.
Is GSDSP Quantum Delay free?
GSDSP Quantum Delay costs $14.99, with no in-app purchases.
Which has better reviews, VariSpeed or GSDSP Quantum Delay?
VariSpeed is rated higher. VariSpeed averages 4.9 out of 5 from 8 ratings, while GSDSP Quantum Delay averages 4.8 from 17 ratings.
Do VariSpeed or GSDSP Quantum Delay have ads?
Neither VariSpeed nor GSDSP Quantum Delay shows ads.
Which is updated more often, VariSpeed or GSDSP Quantum Delay?
VariSpeed ships an update every 41 months, and GSDSP Quantum Delay every 5 weeks. Most recently, VariSpeed was updated on September 10, 2026 and GSDSP Quantum Delay on September 22, 2026.

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