Comparison

Surreal Machines Diffuse vs GSDSP Quantum Filter

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

Head to head
About

Surreal Machines Diffuse

This audio effect plugin blends analog-modeled delay with classic digital reverb, allowing users to morph between the two for unique soundscapes. It offers intuitive control over smearing, echoes, and damping, inspired by vintage hardware.

Highlights
  • Analog-modeled delay
  • Classic digital reverb
  • Morphing between delay and reverb
  • Nonlinearities and tape-style delay
  • Intuitive control over smearing, echoes, damping
  • AUV3 plugin compatibility
Read full description

Diffuse is inspired by classic hardware delay and reverb effects from the 1970’s and 1980’s. It takes a Surreal Machines look at the frontier between delays and reverbs. It's an analog/digital hybrid - an analog modeled delay fused with a classic reverb design used in early digital units. In Diffuse you get more than the best of both worlds - you can morph between delays and reverbs, and find all kinds of fantastical sounds in between the two. You’ll also find plenty of nonlinearities and smooth tape-style delay changes. Diffuse gives you complete control over smearing, echoes and damping in the most intuitive ways possible. ****** Diffuse is an Audio Unit V3 plugin; it benefits from an AUV3 host like Logic, GarageBand, Cubasis, FL Studio Mobile, AUM, etc.

About

GSDSP Quantum Filter

This audio effect plugin offers analog-modeled filters with flexible routing and dynamic modulation for creative sound design. It provides extensive control over tone shaping and complex filtering with various filter types and configurations.

Highlights
  • Analog-modelled filters
  • 11 filter modes
  • Series and parallel routing
  • Dynamic modulation support
  • Stereo and dual mono modes
  • MIDI control integration
Features
Read full description

Analog warmth meets flexible routing and dynamic modulation in a filter workstation built for creative sound design. Analog-Modelled Filters Quantum Filter uses resonant, analog-modelled filter designs that behave smoothly and musically across the entire spectrum. With no cramping, stepping, or digital artefacts, the filters remain stable even under rapid modulation. At high resonance settings they can reach self-oscillation, similar to classic hardware circuits. Filter Types & Routing Choose from 11 filter modes, including Lowpass, Highpass, Bandpass, Notch, Shelving options, Bell, and Ladder Lowpass in 1–4 pole configurations. Combine filters in series (up to three stages) or parallel (up to two), resulting in over 2,000 possible routing combinations for detailed tone shaping and complex layered filtering. Built for Modulation Designed to handle fast, artefact-free modulation, Quantum Filter responds cleanly even under rapid parameter changes. Its stability makes it suitable for dynamic environments, rhythmic modulation, or complex movement across multiple filter stages. Stereo and Dual Mono Switch between stereo and dual mono modes to shape the stereo image. In dual mono mode, left and right channels can move independently, enabling asymmetric movement, wider imaging, or separate modulation paths for each side. MIDI Control Quantum Filter integrates ADSR & AR modulators that respond directly to MIDI, allowing envelope-driven filter motion that behaves like a synthesizer’s filter section. This integration adds expressive control for rhythmic gating, animated sweeps, and dynamic shaping based on your playing or sequencing. Quantum Filter 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

Surreal Machines Diffuse1 screens
GSDSP Quantum Filter3 screens

Verdict

The call

The clearest difference is price: Surreal Machines Diffuse at $7.99 against GSDSP Quantum Filter's $14.99. GSDSP Quantum Filter's advantage is iOS requirement (12.0 vs 14). 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

Surreal Machines Diffuse costs $7.99 and GSDSP Quantum Filter $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 — 5.0 for Surreal Machines Diffuse against 5.0 for GSDSP Quantum Filter. Both are backed by a comparable volume of ratings — 6 and 3 respectively. Written reviews split almost evenly too, at 100% and 100% positive.

Scorecard2 real differences · 8 level
Surreal Machines Diffuse versus GSDSP Quantum Filter: the parameters behind the verdict, then further details
ParameterSurreal Machines DiffuseGSDSP Quantum Filter
Price$7.99 — better$14.99
Rating5.0 (6 ratings)5.0 (3 ratings)
Positive reviews100.0% of reviews100.0% of reviews
Number of ratings6 — better3
Update frequency—Every 5 weeks
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS1412.0 — better
Further details — not scored
Size8 MB77 MB
Age rating4+4+
DeveloperSurreal MachinesGustav Scholda

Customer experience

Surreal Machines Diffuse

All ratings6 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

GSDSP Quantum Filter

All ratings3 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Surreal Machines Diffuse

No in-app purchases

None

GSDSP Quantum Filter

No in-app purchases

Questions

Is Surreal Machines Diffuse free?
Surreal Machines Diffuse costs $7.99, with no in-app purchases.
Is GSDSP Quantum Filter free?
GSDSP Quantum Filter costs $14.99, with no in-app purchases.
Which has better reviews, Surreal Machines Diffuse or GSDSP Quantum Filter?
Surreal Machines Diffuse and GSDSP Quantum Filter are both rated 5.0 out of 5 on the App Store, from 6 and 3 ratings respectively.
Do Surreal Machines Diffuse or GSDSP Quantum Filter have ads?
Neither Surreal Machines Diffuse nor GSDSP Quantum Filter shows ads.

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