Comparison

501 Chorus Echo vs GSDSP Quantum Distortion

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

Head to head
About

501 Chorus Echo

This audio plugin meticulously models the iconic Roland RE-501 Chorus Echo, offering authentic analog warmth with modern digital flexibility. It provides producers with classic tape delay, BBD chorus, and spring reverb sounds, enhanced by DAW tempo sync and expanded controls for any music genre.

Highlights
  • Authentic analog sound reproduction
  • Extended creative control with DAW sync
  • Intuitive user interface
  • Versatile for any music genre
  • Independent SOS timings
  • Linear preamp option
Features
Read full description

"Legendary Analog Warmth: Authentic Spring Reverb, Classic Tape Delay, and Lush BBD Chorus in a Cutting-Edge Plugin" Rediscover the iconic sound of the Roland RE-501 Chorus Echo*, now reborn as the NA 501 Chorus Echo plugin by Nembrini Audio. This meticulously modeled plugin captures the essence of the legendary tape echo, BBD chorus, and spring reverb, enhanced with modern digital functionality for today's music producers. Ideal for adding rich, analog textures to any genre, the NA 501 is a versatile tool for musicians and producers seeking that classic sound with contemporary flexibility. Key Features:: 1 - Authentic Sound Reproduction: Delivers the classic warmth and character of the Roland RE-501 through precise digital modeling. 2 - Extended Creative Control: Offers advanced features like DAW tempo sync, expanded chorus and delay parameters, and independent SOS timings. 3 - Intuitive User Interface: Designed for ease of use, blending vintage aesthetics with modern digital efficiency. 4 - Versatility for Any Genre: Whether you're producing rock, electronic, ambient, or beyond, the NA 501 fits seamlessly into any musical project. Equipped with features tailored for modern production, the NA 501 includes DAW tempo synchronization, a wide parameter range for the BBD chorus and analog tape delay, separate left and right SOS timings, and a linear preamp option. These technical enhancements ensure that the NA 501 not only emulates the classic sound but elevates it to new levels. Works as a standalone app, AudioUnit v3 effect, or Inter-App Audio effect Legal Disclaimer: RE-501 Chorus Echo is a registered trademark of Roland Inc. NA 501 Chorus Echo was developed by Nembrini Audio SRL based on its modeling techniques. Roland has not endorsed nor sponsored the NA 501 Chorus Echo in any manner, nor licensed any intellectual property for use in this product.

About

GSDSP Quantum Distortion

Explore four distinct distortion effects—Saturation, BitCrush, Ring Modulation, and Downsampling—blended and controlled via an intuitive XY pad. Shape harmonics, reduce digital resolution, introduce inharmonic motion, and create classic digital degradation for unique audio textures.

Highlights
  • Four distortion algorithms (Saturation, BitCrush, Ring Modulation, Downsampling)
  • Intuitive XY pad for blending effects
  • Custom waveshaping saturation
  • BitWarp for tonal variation
  • Tunable oscillator for ring modulation
  • Adjustable downsampling rate and jitter
  • AUv3 audio effect plugin
Features
Read full description

Four complementary distortion algorithms — Saturation, BitCrush, Ring Modulation, and Downsampling — blended and shaped through an intuitive XY pad. Saturation Shape harmonics using Quantum Distortion’s custom waveshaping saturation. Adjust Drive to set the intensity from subtle warmth to strong coloration, and use Asymmetry to introduce controlled even-harmonic emphasis of vintage tube characteristics. BitCrush Reduce digital resolution using BitCrush and reshape the crushed signal with BitWarp, which bends the quantization curve for additional tonal variation. This combination allows precise control over both the amount of reduction and the character of the resulting digital artifacts. Ring Modulation Introduce inharmonic motion using ring modulation, generated by multiplying the input with a tunable oscillator. Adjust frequency and amount in real time to create anything from light metallic shading to dense, shifting sidebands. Downsampling Lower the sample rate using Downsampling, reducing temporal resolution for classic digital degradation effects. Set the rate down to 200 Hz or introduce Jitter for controlled randomness, adding instability and movement to the downsampled signal. XY Pad Blending Navigate between the four distortion algorithms using the XY pad, allowing smooth transitions or static blends across the processing modes. The background updates to reflect the current region, providing clear visual feedback while exploring hybrid distortion shapes and interactions. Quantum Distortion 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

501 Chorus Echo1 screens
GSDSP Quantum Distortion3 screens

Verdict

The call

The clearest difference is review sentiment: GSDSP Quantum Distortion at 100% against 501 Chorus Echo's 0%. GSDSP Quantum Distortion also leads on rating (5.0 vs 4.5) and update cadence (every 5 weeks vs every 17 months). On price, ratings volume, ads and in-app purchases 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

501 Chorus Echo costs $14.99 and GSDSP Quantum Distortion $14.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

GSDSP Quantum Distortion holds the better App Store score, 5.0 against 4.5. Both are backed by a comparable volume of ratings — 8 and 10 respectively. Written reviews point the same way: 0% of 501 Chorus Echo's written reviews are positive against 100% of GSDSP Quantum Distortion's.

UpkeepUpdate frequency

501 Chorus Echo ships an update every 17 months, GSDSP Quantum Distortion every 5 weeks. The most recent releases landed on October 13, 2026 and October 9, 2026 respectively.

Scorecard4 real differences · 6 level
501 Chorus Echo versus GSDSP Quantum Distortion: the parameters behind the verdict, then further details
Parameter501 Chorus EchoGSDSP Quantum Distortion
Price$14.99$14.99
Rating4.5 (8 ratings)5.0 (10 ratings) — better
Positive reviews0.0% of reviews100.0% of reviews — better
Number of ratings810 — better
Update frequencyEvery 17 monthsEvery 5 weeks — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS1512.0 — better
Further details — not scored
Size23 MB80 MB
Age rating4+4+
DeveloperNembrini AudioGustav Scholda

Customer experience

501 Chorus Echo

All ratings8 ratings
Positive87.5%
Neutral0.0%
Negative12.5%
Written reviews1 reviews
Positive0.0%
Neutral0.0%
Negative100.0%

GSDSP Quantum Distortion

All ratings10 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews3 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

501 Chorus Echo

No in-app purchases

None

GSDSP Quantum Distortion

No in-app purchases

Questions

Is 501 Chorus Echo free?
501 Chorus Echo costs $14.99, with no in-app purchases.
Is GSDSP Quantum Distortion free?
GSDSP Quantum Distortion costs $14.99, with no in-app purchases.
Which has better reviews, 501 Chorus Echo or GSDSP Quantum Distortion?
GSDSP Quantum Distortion is rated higher. 501 Chorus Echo averages 4.5 out of 5 from 8 ratings, while GSDSP Quantum Distortion averages 5.0 from 10 ratings.
Do 501 Chorus Echo or GSDSP Quantum Distortion have ads?
Neither 501 Chorus Echo nor GSDSP Quantum Distortion shows ads.
Which is updated more often, 501 Chorus Echo or GSDSP Quantum Distortion?
501 Chorus Echo ships an update every 17 months, and GSDSP Quantum Distortion every 5 weeks. Most recently, 501 Chorus Echo was updated on October 13, 2026 and GSDSP Quantum Distortion on October 9, 2026.

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