Comparison

Audio Function Generator PRO vs King of Digital D1

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

Head to head
About

Audio Function Generator PRO

Generate various audio test tones, including sine, square, and sawtooth waves. Explore frequency and volume sweeps, custom presets, and different types of noise. Advanced settings allow for fine-tuning signal parameters and creating complex multi-tone sequences.

Highlights
  • Generate sine, square, triangular, and sawtooth tones
  • Frequency and volume sweep generation
  • Customizable presets and configurations
  • Multiple noise types (White, Pink, Violet, etc.)
  • Advanced signal parameter control
  • Multi-tone and dual function generation
Features
Read full description

This is the highly recommended and praised Function Generator App - an amazingly great and powerful tone generator. Enriched with a vast amount of features yet it is extremely intuitive and designed for simplicity. Get to know this great App now! It is very well maintained and has received considerable upgrades over the past years. So, … what can you do with this App? • PLAY TEST TONES Sine, Rectangular, Triangular and Sawtooth. • PLAY FREQUENCY SWEEP TEST TONES in both directions (minimum to maximum frequency and maximum to minimum frequency). • PLAY VOLUME SWEEPS (from minimum to maximum volume). • Try the SWEEP REPEAT / WOBBLE function. • Try the MUSIC TONES PLAYBACK. • Experiment with the huge FINE TUNE SELECTON, PRESETS SELECTION! • Or create your own CUSTOM PRESETS! • And SAVE an endless amount of CONFIGURATIONS (Frequency, Sweep, Noise) for later quick access and direct playback function. • Even play back different kinds of NOISE – White, Pink, Violet, Grey, Brown, Blue is also supported. The Function Generator is AMAZINGLY INTUITIVE and SIMPLE! AND THESE ARE THE ADVANCED SETTINGS/FEATURES: => Extending The Frequency Range (1Hz - 21kHz) => Extending The Sweep Times (0.1s - 600s) => Changing Min/Max Slider Frequency Ranges => Changing Max Sweep Time Slider Range => Changing Signal Amplitude => Enabling Of The Sweep Repeat / Wobble Function => Frequency Slider Setting to Linear or Logarithmic => Left/Right Channel Individual Selection => Permanently Saving Custom Presets => Saving Of Endless Number Of Audio Configurations => Phase Out Setting (custom phase shift of the generated signal) => BPM (Beats per Minute) Feature => Dual Function Generator => MultiTone Generator (playback of up to eight individual tones) => Background Theme Selection (Light/Dark) Check out the new Tutorial page: www.ee-toolkit.com/audio-function-generator

About

King of Digital D1

This app is a virtual analog and PCM synthesizer inspired by iconic digital synths from the 80s, 90s, and 2000s. It offers over 900 presets, extensive sound design capabilities, and can be used as a plug-in in various DAWs.

Highlights
  • 64-voice Hybrid Digital PCM & VA Synth
  • 900+ Handmade Presets
  • Dual Layers per Voice
  • Vintage-style Step Sequencer
  • 3 LFOs with Fun Routings
  • Integrated FX Suite
  • AUv3 Plug-in Support
Features
Currently charting
Read full description

Epic 64-voice Virtual Analog / PCM iPad Synth Inspired by the Digital Synths of the 80s, 90s, 2000s FULLY LOADED w/ 900+ presets by Analog Matthew, Brice Beasley, DMT Cymatics, Moby Pixel, Red Sky Lullaby, Jakob Haq, Electronisounds (Dean Daughters), Sound of Izrael, Brian Funk, and more "A Perfect Synth" - App Advice "Fans of the D-50, JD-990, 01/W, Wavestation... Rejoice!" - Music Radar Includes iPhone, iPad and iOS AUv3 versions: Use as a plug-in in DAWs like GarageBand & Logic for iPad, Cubasis, AUM, and more! The Sound. Oh, the sound. You won't believe it. BONUS: This app is packed with 5 PCM banks of sounds, including the Digital D1 PCMs, and D1 Expanion bank. This is a Premium App: No iAP, No Ads, No subsciptions! One low price includes Lifetime License and all Expansions! KING OF DIGITAL • 64-voice Hybrid Digital PCM & VA Synth • 3+ Gigabyte of original samples recorded from analog & fm synths over 30+ years old • Space-saving Compression - The whole app is under 500mb! • Dual layers per voice. Keyboard splits • Vintage-style Step Sequencer that can be routed to specific layers. • 3 LFOs. Fun Routings. LFOs can modify other LFOs • iPad version has "stacked" views for maximum onscreen control! • Too many features to mention... ADDITIONAL FEATURES: • 900+ Handmade presets, lovingly crafted by human sound designers, no AI! • FX: Glorious Reverb, Phaser, Digital Delay, Distortion, Flanger, Chorus, Crush, and more. • Perfect with a MIDI Keyboard *** BONUS *** ************************************** FEATURES ALL THE SOUNDS OF DIGITAL D1: ************************************** "D1 Sounds awesome... Get this app!" - Sonic State, Featured D1 on Podcast & Live Video Stream "Digital D1 synth is pure ‘80s and ‘90s digital lushness" - Computer Music/Music Radar "Beautiful. Lush. Modern and Amazing… An Instant Classic." Easy to use. Easy to get great tone. You want great sound right away? It has tons of presets. Plus, the ability to easily manipulate sounds with filters, delays, and other FX. D1 SOUNDS, USER REVIEWS: "The Best Synth For iOS [period]" "I've been playing synths for 35 years. And, this is as good as it gets" "The Sound... Perfect!" "Breathtaking Presets, right out-of-the box" "The sound quality competes with hardware synths" • Mod Wheel can morph between layers. Start with an Electric Piano, and slowly bring in Strings with your MIDI controller. • Create beautiful live performances using a MIDI keyboard • Epic pads that will inspire you ** This app does not sample any PCM-based synths, including Roland or Korg digital keyboards. Additionally, this app does not have any business relationship with Roland, Korg, or any other 80s/90s Digital Synth manufacturers. *** All app sounds were created by pure analog synthesis and fm synthesis. We took these new sounds. Stacked them. Flipped them. And, processed the heck out of ’em. Resulting in a beautiful new sonic palette for you to enjoy.

Screenshots

Audio Function Generator PRO4 screens
King of Digital D14 screens

Verdict

The call

The clearest difference is chart position: King of Digital D1 at #112 against Audio Function Generator PRO's unranked. King of Digital D1 also leads on price ($7.99 vs $9.99) and ratings volume (1.3K vs 269). On rating, review sentiment, update cadence 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

Audio Function Generator PRO costs $9.99 and King of Digital D1 $7.99 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 — 4.8 for Audio Function Generator PRO against 4.9 for King of Digital D1. Both are backed by a comparable volume of ratings — 269 and 1.3K respectively. Written reviews are what separate them: 88% of Audio Function Generator PRO's written reviews are positive against 92% of King of Digital D1's.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly every 6 weeks. The most recent releases landed on October 29, 2026 and October 30, 2026 respectively.

Scorecard5 real differences · 6 level
Audio Function Generator PRO versus King of Digital D1: the parameters behind the verdict, then further details
ParameterAudio Function Generator PROKing of Digital D1
Price$9.99$7.99 — better
Rating4.8 (269 ratings)4.9 (1.3K ratings) — better
Positive reviews87.9% of reviews92.5% of reviews — better
Number of ratings2691.3K — better
Update frequencyEvery 6 weeksEvery 6 weeks
AdsNoNo
In-app purchasesNoNo
MonetizationFree — betterPaid
Best chart rank—#112 — better
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS16.014.4 — better
Further details — not scored
Size13 MB444 MB
Age rating4+4+
DeveloperThomas GruberAudioKit Pro

Customer experience

Audio Function Generator PRO

All ratings270 ratings
Positive94.8%
Neutral2.6%
Negative2.6%
Written reviews58 reviews
Positive87.9%
Neutral5.2%
Negative6.9%

King of Digital D1

All ratings1,248 ratings
Positive98.6%
Neutral0.8%
Negative0.6%
Written reviews146 reviews
Positive92.5%
Neutral4.1%
Negative3.4%

User reviews

Audio Function Generator PRO

From 269 App Store ratings

What we love

  • ✨ Superb craftsmanship and work
  • 🚀 Excellent performance on older devices
  • 💡 History feature is a great addition
  • 👍 Versatile and powerful app
  • 🎶 Great for binaural beats and sound creation

Room to improve

  • 📉 Linear sweep is useless
  • ❓ Missing PWM functionality
  • ❓ Missing Terzrauschen (third-octave noise)
  • 🐛 Volume button issues
  • 🐛 GUI is bad

King of Digital D1

From 1.3K App Store ratings

What we love

  • 🎨 Awesome sounds
  • 🎹 Lots of usable presets
  • 🎚️ Powerful and customizable
  • 💰 Great value for money
  • 🎶 Inspirational and creative

Room to improve

  • 🐛 Occasional crashes or bugs
  • 🔌 Compatibility issues with some DAWs
  • 🗂️ Favorites list can be unstable with many presets

Bugs and requests

Audio Function Generator PRO

Reported bugs

6 issues
  • Volume button issues (jumps up and down, displays wrong level)
  • Update crashes on iPad Air2 when changing screens
  • App opens AppStore repeatedly after purchase
  • Buttons don't respond, settings don't keep
  • Frequencies stick, program is useless
Show 1 more
  • App stops too much

Requested features

19 requests
  • Logarithmic sweeps and frequency slider scale
  • PWM functionality
  • Terzrauschen (third-octave noise)
  • Ping-pong sweeps in Multitone windows
  • Sweeping of noise/adding noise in Multitone sweep with sweeping bandpass filter
Show 14 more
  • Audio plugin (AU, AAX, VST)
  • Responsiveness for MacBook use
  • Simultaneous recording of generated signals
  • Panning function for tones and sweeps
  • Ability to save Multitone configurations
  • Phase shift functionality
  • Higher frequency range (up to 24kHz)
  • Dual mode sweep function
  • Taper function
  • Extended time for sweeps (6-8 hours)
  • Ability to stay at selected frequency for several minutes
  • Spectrum analyzer
  • Separate control for left and right channels
  • 8-hour program for sleep entrainment

King of Digital D1

Reported bugs

2 issues
  • High D key gets stuck on some devices
  • Presets dropdown menu doesn't retract properly

Requested features

3 requests
  • Add arpeggiator functionality
  • Improve sequencer and timing reliability
  • Allow use on Mac devices

In-app purchases

None

Audio Function Generator PRO

No in-app purchases

None

King of Digital D1

No in-app purchases

Questions

Is Audio Function Generator PRO free?
Audio Function Generator PRO costs $9.99, with no in-app purchases.
Is King of Digital D1 free?
King of Digital D1 costs $7.99, with no in-app purchases.
Which has better reviews, Audio Function Generator PRO or King of Digital D1?
King of Digital D1 is rated higher. Audio Function Generator PRO averages 4.8 out of 5 from 269 ratings, while King of Digital D1 averages 4.9 from 1.3K ratings.
Do Audio Function Generator PRO or King of Digital D1 have ads?
Neither Audio Function Generator PRO nor King of Digital D1 shows ads.
Which is updated more often, Audio Function Generator PRO or King of Digital D1?
Audio Function Generator PRO ships an update every 6 weeks, and King of Digital D1 every 6 weeks. Most recently, Audio Function Generator PRO was updated on October 29, 2026 and King of Digital D1 on October 30, 2026.

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