Comparison

S vs PaSSBot

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

Head to head
About

S

This semi-modular synthesizer app for iPad offers a hands-on sound design experience with a single-screen interface for intuitive patching. It delivers a warm, vintage sound inspired by 1970s synthesizers, featuring dual oscillators, resonant filters, and multiple modulation sources.

Highlights
  • Single-screen interface
  • Fast, hands-on patching
  • Vintage 1970s synth sound
  • Dual oscillators
  • Resonant ladder filter
  • Multiple modulation sources
Features
Read full description

S-Modular is a semi-modular synthesiser for iPad, designed for fast, hands-on patching without clutter. Everything is presented on a single screen, making sound design immediate and intuitive. Simply drag from one jack to another to create connections. S-Modular delivers a distinctive vintage sound inspired by classic 1970s synthesis — warm, rich, and full of character. Features Dual oscillators 24 dB/oct ladder filter Resonant high-pass and low-pass filters Two LFOs Four-step CV sequencer Four-track mixer Audio and CV splitter Two AHR envelope generators Delay effect

About

PaSSBot

This app is a stochastic filter bank audio processor for iPad, offering advanced sound manipulation with various filter types and powerful stochastic generators. It allows for precise control over filter parameters and harmonic distribution, ideal for creating complex audio textures.

Highlights
  • Stochastic filter bank audio processor
  • Multiple filter types (Biquad, Ladder, SEM, Resonators)
  • Up to 64 filters in stereo
  • Powerful stochastic generators
  • Individual filter parameter control
  • Harmonic distribution options
  • Precision DSP rendering (<1ms control rate)
Read full description

PaSSBot is a unique stochastic filter bank audio processor. The desktop VST/AU version of PaSSbot has already arrived in February 2020 and this iOS version is equivalent to the latest version 2.1. PaSSBot filter types are Biquad, StateVariableFilter, Ladder, SEM and Resonators. With behaviors of bandpass, Lo + Hipass, Notch and up to 64 of them in true stereo ! The user can set values of center frequency, gain and resonance of the each filter, which will be then eloborated with powerful stochastic generators ( 4 independent GENs for each filter ) with continuous or discrete probabilistic distributions but also with standard waveforms. One can set each filter parameters individually, but also distribute them in harmonic order, again the harmonic spread ratio can be set by the user or even can be modulated by a GEN. Precision DSP rendering, less than 1milisec. control rate precision. The filters can run continuously or be triggered manually. In that case, each filter will be applied an independent AR envelope with configurable random duration. Important notes : - A recent iPAD model is being recommended and also setting the host buffer size to 128 or higher greatly helps to the CPU needs which also heavily depends on the number of parallel filters being used. - The resonators can be sensitive to input signal level. - The PaSSBot manual can be found at this link. https://www.sonic-lab.com/PaSSBot_files/PassBot_manual.pdf sonicLAB PaSSBot youtube playlist : https://www.youtube.com/playlist?list=PLP0cOkraQHDYUoMG6BETTN1eGm-Kq5z0T

Screenshots

S2 screens

Verdict

The call

The clearest difference is review sentiment: PaSSBot at 100% against S's 31%. PaSSBot also leads on rating (5.0 vs 2.6) and iOS requirement (11.0 vs 15.6). S's advantage is price ($2.99 vs $34.99) and device support (3 vs 1). On ratings volume, update cadence, 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

S costs $2.99 and PaSSBot $34.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

PaSSBot holds the better App Store score, 5.0 against 2.6. Both are backed by a comparable volume of ratings — 11 and 8 respectively. Written reviews point the same way: 31% of S's written reviews are positive against 100% of PaSSBot's.

UpkeepUpdate frequency

S ships an update every 7 months, PaSSBot every 4 months. The most recent releases landed on September 19, 2026 and June 30, 2026 respectively.

Scorecard5 real differences · 5 level
S versus PaSSBot: the parameters behind the verdict, then further details
ParameterSPaSSBot
Price$2.99 — better$34.99
Rating2.6 (11 ratings)5.0 (8 ratings) — better
Positive reviews31.3% of reviews100.0% of reviews — better
Number of ratings11 — better8
Update frequencyEvery 7 monthsEvery 4 months — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
DevicesiPhone, iPad, iPod — betteriPad
Requires iOS15.611.0 — better
Further details — not scored
Size7 MB11 MB
Age rating4+4+
DeveloperPaul BetowskiSonicPlanet Audio Video Teknolojileri Anonim Sti.

Customer experience

S

All ratings11 ratings
Positive27.3%
Neutral27.3%
Negative45.5%
Written reviews16 reviews
Positive31.3%
Neutral25.0%
Negative43.8%

PaSSBot

All ratings8 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

S

No in-app purchases

None

PaSSBot

No in-app purchases

Questions

Is S free?
S costs $2.99, with no in-app purchases.
Is PaSSBot free?
PaSSBot costs $34.99, with no in-app purchases.
Which has better reviews, S or PaSSBot?
PaSSBot is rated higher. S averages 2.6 out of 5 from 11 ratings, while PaSSBot averages 5.0 from 8 ratings.
Do S or PaSSBot have ads?
Neither S nor PaSSBot shows ads.
Which is updated more often, S or PaSSBot?
S ships an update every 7 months, and PaSSBot every 4 months. Most recently, S was updated on September 19, 2026 and PaSSBot on June 30, 2026.

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