Comparison

iChromatic vs Audulus 4

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

Head to head
About

iChromatic

This app provides precise instrument tuning using your device's microphone and a visual strobe display. It offers frequency readouts and responsive waterfall strobes for accurate pitch matching. Configure reference frequencies and tune a wide range of notes.

Highlights
  • Visual strobe display for tuning
  • Frequency readout in Hz and cents
  • Accurate waterfall strobe panes
  • Concert A reference frequency adjustment
  • Wide tuning range
Read full description

The HotPaw iChromatic Strobe Tuner uses the built-in microphone on your iPhone to allow you to tune a musical instrument rapidly and precisely via an animated visual display. For your iPad, please see the iChromatic Strobe Tuner HD. For guitar tuning, please see the HotPaw inTuna Strobe Guitar Tuner. Both of these apps are also here in the iOS app store. iChromatic includes both a frequency readout and 3 highly accurate and responsive waterfall strobe panes which allow extremely precise tuning. When the waveform patterns line up vertically as well as stop moving sideways in the strobe panes, this indicates that the input pitch (or a strong harmonic of the pitch) matches the frequency of the nearest equal temperament note. With the waterfall strobe tuning window, even very slight differences in frequency between the pitch detected and the target perfect pitch will cause the abstract waveform to waver or move sideways as it cascades down the strobe window. iChromatic also includes a pitch frequency readout in Hz and cents. Configuration options include a Concert A reference frequency adjustment in both Hz and Cents. Please try the Free inTuna A440 app, also in the iOS App store, before purchasing iChromatic, to see if you appreciate the advantages of using a strobe tuner. Tuning range using the built-in iPhone microphone is from 2 octaves above middle-C to 2 octaves below.

About

Audulus 4

Create and shape sounds with a professional-grade modular synthesizer environment. Explore a vast library of modules for synthesis and sound design, with the option to expand your toolkit with premium instruments and effects. Available across Apple devices for seamless workflow.

Highlights
  • Modular synthesizer environment
  • Sound design tools
  • Real-time audio shaping
  • Extensive module library
  • Premium Pro Modules (in-app purchases)
  • Cross-device iCloud sync
  • AUv3 plugin support
Features
Read full description

Build synthesizers. Design sounds. Shape audio in real time. All with professional-grade, low-latency performance ready for live use — and it’s free. Audulus gives you a complete modular environment at no cost. Its clean, fluid interface stays out of the way so you can focus on what matters: exploring sound. A modular playground with room to grow — from first experiments to advanced designs. Looking for more? Discover the Pro Module series: premium instruments and effects that show what’s possible when world-class sound design meets true modular freedom. Each Pro Module is crafted specifically for Audulus, giving you new ways to expand your sonic toolkit. Available on iPhone, iPad, and Mac — your modular system travels with you. ▶ What People Are Saying: "gem for Apple platforms – gorgeous, fluid" — Peter Kirn, createdigitalmusic.com "stunning!" — Richard Devine, devinesound.net "Remarkable gesture control" — sequencer.de ▶ Join our forum and Discord community! ▶ What You Get: • Complete modular environment — free to download and explore • Pro Module series — premium modules available as in-app purchases • Available on iPhone, iPad, and Mac with iCloud sync • Standalone app or AUv3 plugin • Deep node library for building from scratch • Extensive module library for synthesis and sound design • Multi-channel signal flow for polyphony and complex routing • Next-gen multi-core audio processing • Smooth, high-performance graphics even with massive patches • MIDI I/O with MIDI learn • GLSL shader node for creating advanced visuals • Lua scripting for custom DSP and vector graphics Terms of Use: https://audulus.com/terms.html

Screenshots

iChromatic2 screens
Audulus 44 screens

Verdict

The call

The clearest difference is price: Audulus 4 at Free against iChromatic's $19.99. Audulus 4 also leads on rating (4.3 vs 3.0) and update cadence (monthly vs every 15 months). iChromatic's advantage is in-app purchases (none vs 27) and iOS requirement (12.0 vs 18.0). On ads and device support 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

Audulus 4 is free to download; iChromatic costs $19.99 up front. Audulus 4 sells 27 in-app purchases, starting at $4.99 per month. iChromatic asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Audulus 4 holds the better App Store score, 4.3 against 3.0. That said, the two scores are not equally well evidenced: Audulus 4 has 74 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 50% of iChromatic's written reviews are positive against 69% of Audulus 4's.

UpkeepUpdate frequency

iChromatic ships an update every 15 months, Audulus 4 monthly. The most recent releases landed on October 8, 2026 and October 22, 2026 respectively.

Scorecard8 real differences · 2 level
iChromatic versus Audulus 4: the parameters behind the verdict, then further details
ParameteriChromaticAudulus 4
Price$19.99Free — better
Rating3.0 (1 ratings)4.3 (74 ratings) — better
Positive reviews50.0% of reviews69.2% of reviews — better
Number of ratings174 — better
Update frequencyEvery 15 monthsMonthly — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationPaidFree with in-app purchases — better
DevicesiPhone, iPodiPhone, iPad, Mac — better
Requires iOS12.0 — better18.0
Further details — not scored
Size1 MB103 MB
Age rating4+4+
DeveloperHotPaw ProductionsAudulus LLC

Customer experience

iChromatic

All ratings1 ratings
Positive0.0%
Neutral100.0%
Negative0.0%
Written reviews4 reviews
Positive50.0%
Neutral50.0%
Negative0.0%

Audulus 4

All ratings74 ratings
Positive82.4%
Neutral4.1%
Negative13.5%
Written reviews78 reviews
Positive69.2%
Neutral10.3%
Negative20.5%

Bugs and requests

iChromatic

Not enough reviews yet to summarise bugs or requests.

Audulus 4

Reported bugs

13 issues
  • iOS 18 compatibility issues (app not working)
  • Save presets but no 'Load' button
  • Undo command issues with DAWs
  • CMD+Z causing data loss
  • Opt+drag not duplicating modules
Show 8 more
  • Plugin window not resizable
  • Menu filtering not functioning properly on iPhone
  • Select and Import buttons not working
  • Blank screen on open
  • App freezes on iPad Pro
  • Black screen on launch after update
  • No modules appearing after iOS 18 update
  • Patches not appearing after iOS 18 update

Requested features

7 requests
  • Add 'Load' button for presets
  • Improve DAW integration (Undo, duplicate)
  • Resizable plugin window
  • More modules (FFT/IFFT, granular buffering)
  • Add CC in module
Show 2 more
  • Sync to host as AUv3
  • Make upgrade path clearer from Audulus 3

In-app purchases

None

iChromatic

No in-app purchases

27 purchases

Audulus 4

Subscriptions2
  • Audulus Pro (1 Month)7 Days trial$4.991 Month
  • Audulus Pro (1 Year)7 Days trial$29.991 Year
One-time25
  • 1-shot Sample$1.99
  • P-Train$2.99
  • CLK RS-1$3.99
Show 22 more
  • CG-1 Chord Generator$3.99
  • CLK Clock Generator$4.99
  • MetaEnvelope$4.99
  • Modal Percussion$4.99
  • CLK: TimeWarp$4.99
  • CPR-1$4.99
  • LMT-1$4.99
  • MS-FUNC$5.99
  • CLK SS-516$7.99
  • J-23 Reverb$7.99
  • J-23 Effects$7.99
  • CLK GS-1$7.99
  • Chaos LFO Bundle$7.99
  • ARP-1$7.99
  • CPR-3$7.99
  • SynD-K1$7.99
  • TRIKOR VCO$9.99
  • CLK Tools Bundle$9.99
  • Essential Synth Bundle$9.99
  • VCF Bundle 1$9.99
  • J-23 Space Console$14.99
  • Patch Editing$29.99

Questions

Is iChromatic free?
iChromatic costs $19.99, with no in-app purchases.
Is Audulus 4 free?
Audulus 4 is free to download, with in-app purchases available.
Which has better reviews, iChromatic or Audulus 4?
Audulus 4 is rated higher. iChromatic averages 3.0 out of 5 from 1 ratings, while Audulus 4 averages 4.3 from 74 ratings.
Do iChromatic or Audulus 4 have ads?
Neither iChromatic nor Audulus 4 shows ads.
Which is updated more often, iChromatic or Audulus 4?
iChromatic ships an update every 15 months, and Audulus 4 monthly. Most recently, iChromatic was updated on October 8, 2026 and Audulus 4 on October 22, 2026.

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