Comparison

Synesthesia Synth vs Callback Freeverb

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

Head to head
About

Synesthesia Synth

An experimental audio-visual instrument that allows users to sculpt evolving spatial audio by manipulating floating capsules. Position, rotation, and pulse changes affect tone, texture, and synchronized particle generation. It's a visual synthesizer, not a game.

Highlights
  • Experimental audio-visual instrument
  • Sculpt evolving spatial audio
  • Manipulate floating capsules
  • Control tone, texture, and particles
  • Visual synthesizer
Read full description

Synthaestesia is a free experimental audio-visual instrument. Three capsules float in space. Every contraction produces sound. Move them, rotate them, reshape their pulse — and sculpt evolving spatial audio. Position changes tone. Rotation alters texture. Delay generates synchronized particles. This is not a game. It’s a spatial synth you can see.

About

Callback Freeverb

This app offers a classic algorithmic reverb effect based on the Freeverb algorithm. It adds depth, space, and atmosphere to audio sources, creating lush, spacious ambience. Designed for mono use, it provides a smooth, musical reverb tail suitable for vocals and synthesizers.

Highlights
  • Classic Freeverb algorithm
  • Schroeder/Moorer reverb topology
  • Comb and allpass filters
  • Mono operation
  • Adds depth and space to audio
  • Smooth, musical reverb tail
Features
Read full description

A classic algorithmic reverb effect based on the Freeverb algorithm by Jezar at Dreampoint. A Freeverb-style Schroeder/Moorer reverb based on the classic 8-comb + 4-allpass topology, with simplified controls and no stereo spread. This reverb creates lush, spacious ambience through a network of comb and allpass filters. Freeverb is widely used in electronic music production, ambient music, and sound design to add depth, space, and atmosphere to audio sources. The algorithm provides a smooth, musical reverb tail that works well on everything from vocals to synthesizers. This reverb only functions in mono and provides no stereo imaging, and the user can expect the same behavior as a classic Freeverb implementation otherwise.

Screenshots

Synesthesia Synth2 screens
Callback Freeverb4 screens

Verdict

The call

Synesthesia Synth and Callback Freeverb are too close to call on the numbers: across 8 compared parameters — price, rating, ratings volume and ads among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

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

Both are free to download. 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 Synesthesia Synth against 5.0 for Callback Freeverb. Both are backed by a comparable volume of ratings — 2 and 1 respectively.

ScorecardNo meaningful differences
Synesthesia Synth versus Callback Freeverb: the parameters behind the verdict, then further details
ParameterSynesthesia SynthCallback Freeverb
PriceFreeFree
Rating5.0 (2 ratings)5.0 (1 ratings)
Number of ratings2 — better1
Update frequencyEvery 10 days—
AdsNoNo
In-app purchasesNoNo
MonetizationFreeFree
DevicesiPhone, iPadiPhone, iPad
Requires iOS16.0 — better17.0
Further details — not scored
Size141 MB7 MB
Age rating4+4+
DeveloperMICHELE ZACCAGNINICallback Audio, LLC

In-app purchases

None

Synesthesia Synth

No in-app purchases

None

Callback Freeverb

No in-app purchases

Questions

Is Synesthesia Synth free?
Synesthesia Synth is free to download, with no in-app purchases.
Is Callback Freeverb free?
Callback Freeverb is free to download, with no in-app purchases.
Which has better reviews, Synesthesia Synth or Callback Freeverb?
Synesthesia Synth and Callback Freeverb are both rated 5.0 out of 5 on the App Store, from 2 and 1 ratings respectively.
Do Synesthesia Synth or Callback Freeverb have ads?
Neither Synesthesia Synth nor Callback Freeverb shows ads.

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