Comparison

Decibel X vs Audio Function Generator

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

Head to head
About

Decibel X

This app transforms your device into a professional sound level meter, precisely measuring ambient noise pressure. It offers advanced features like frequency analysis, historical data management, and dosimeter functions, making it useful for various applications and entertainment.

Highlights
  • Precise sound pressure level measurement
  • Frequency spectrum analysis (FFT, BAR graphs)
  • Historical data recording and export
  • Dosimeter with NIOSH, OSHA standards
  • Apple Watch and Health App integration
  • Customizable calibration and filters
Features
Currently charting
Read full description

"Decibel X" is one of very few noise meter apps on the market that has highly reliable, pre-calibrated measurements and supports dBA, dBC. It turns your iOS device into a professional sound level meter, precisely measures the sound pressure level (SPL) all around you. This extremely useful and beautiful tool will not only be a great tool for many uses but also bring you a lot of fun. Have you wondered how quiet is your room or how loud is a rock concert or sport event? "Decibel X" will help you answer all of those. WHAT MAKE IT GREAT AND STAND OUT FROM OTHER APPS: - Trusted accuracy: the app is tested and pre calibrated for all Apple devices. The precision is matching with real SPL devices - Apple Watch support: see noise level right from your wrist - Health App integration: export noise levels directly into Health app - Frequency weighting filters: ITU-R 468, A, B, C, Z - Powerful, smart history data management: + Recording data can be saved into a list of history records for future access and analysis + Each record can be exported as hi-res PNG graph or CSV text via sharing services + iCloud support which synchronize all history records across your Apple devices + Fullscreen mode to give overview the whole history of an record - Dosimeter with NIOSH, OSHA standards - Powerful calibration: Linear, Octave 1/1, 1/3, Load/save profile - FFT and BAR graphs to display real time FFT. Those are very useful for frequency analysis and musical tests. Real time predominant frequency is also displayed. - InstaDecibel to capture your dB report overlaid on photos and easily shared via popular social networks (Facebook, Instagram, Messages, etc.). - Support Live Activity, Dynamic Island - Support both Portrait and Landscape layouts - Beautiful, intuitive and carefully crafted UI design. Themes: LIGHT, DARK and CLASSIC OTHER GREAT FEATURES: - Standard time weightings (Response Time): SLOW (500 milliseconds), FAST (200 milliseconds) AND IMPULSE (50 milliseconds) - MIC Gain Offset from -50 dB to 50 dB - Standard measurement range from 30 dBA up to 130 dBA - HISTO graph for plotted history of the recorded values - WAVE graph with 2 display modes: Rolling & Buffer - SPECTROGRAPH - Real time scale level chart - Display Current, Average/Leq, and Max values with both nice and clear digital and analog layouts - Quick reference text to help you compare with real-life examples NOTES: - Please do not expect a quiet room reading will be 0 dBA. The range 30-130 dBA is the standard usable range and an average quiet room will be about 30 dBA. - Although all devices are pre-calibrated, custom calibration is suggested for serious purposes requiring higher precision and accuracy. You will need a real external device or calibrated sound meter as a reference, then adjust the trimming calibration until the reading matches with the reference. * Privacy Policy: http://www.skypaw.com/decibelx/privacy_policy.html * EULA: http://www.skypaw.com/decibelx/terms.html

About

Audio Function Generator

Generate various audio test tones, including sine, square, triangle, and sawtooth waves. Explore frequency and volume sweeps, noise generation, and custom preset creation. Advanced features like extended frequency ranges and multi-tone playback are available with an upgrade.

Highlights
  • Generate sine, square, triangle, and sawtooth tones
  • Frequency and volume sweep generation
  • Noise generation (white, pink, violet, etc.)
  • Custom preset creation and saving
  • Extended frequency range (PRO feature)
  • Multi-tone playback (PRO feature)
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 to use! AND THESE ARE THE ADVANCED SETTINGS/FEATURES (upgrade to PRO required): => 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 tutorial page: www.ee-toolkit.com/audio-function-generator

Screenshots

Decibel X4 screens
Audio Function Generator4 screens

Verdict

The call

The clearest difference is ratings volume: Decibel X at 162K against Audio Function Generator's 2.2K. Decibel X also leads on chart position (#207 vs unranked). Audio Function Generator's advantage is review sentiment (77% vs 61%) and update cadence (every 6 weeks vs every 3 months). On price, rating, 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

Both are free to download. Decibel X sells 5 in-app purchases, starting at $1.99 per 7 days and Audio Function Generator sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.6 for Decibel X against 4.7 for Audio Function Generator. That said, the two scores are not equally well evidenced: Decibel X has 162K ratings behind it against 2.2K, so its average is the more settled of the two. Written reviews are what separate them: 61% of Decibel X's written reviews are positive against 77% of Audio Function Generator's.

UpkeepUpdate frequency

Decibel X ships an update every 3 months, Audio Function Generator every 6 weeks. Both last shipped on September 24, 2026.

Scorecard5 real differences · 6 level
Decibel X versus Audio Function Generator: the parameters behind the verdict, then further details
ParameterDecibel XAudio Function Generator
PriceFreeFree
Rating4.6 (162K ratings)4.7 (2.2K ratings) — better
Positive reviews61.3% of reviews77.1% of reviews — better
Number of ratings162K — better2.2K
Update frequencyEvery 3 monthsEvery 6 weeks — better
AdsNoNo
In-app purchasesYesYes
MonetizationFree with in-app purchasesFree with in-app purchases
Best chart rank#207 — better
DevicesiPhone, iPad, Apple WatchiPhone, iPad, iPod
Requires iOS17.015.5 — better
Further details — not scored
Size90 MB14 MB
Age rating4+4+
DeveloperSkyPaw Co., LimitedThomas Gruber

Customer experience

Decibel X

All ratings161,895 ratings
Positive92.3%
Neutral3.5%
Negative4.2%
Written reviews804 reviews
Positive61.3%
Neutral4.2%
Negative34.5%

Audio Function Generator

All ratings2,191 ratings
Positive91.8%
Neutral3.1%
Negative5.1%
Written reviews271 reviews
Positive77.1%
Neutral6.3%
Negative16.6%

User reviews

Decibel X

From 162K App Store ratings

What we love

  • ⭐ Excellent app
  • 👍 Easy to use and understand
  • 🔍 Useful for various applications
  • 🎓 Helpful for hearing protection
  • 🔧 Accurate and reliable

Room to improve

  • 💰 Expensive subscription model
  • 🔒 Misleading free trial
  • 📢 Intrusive ads
  • 🤖 Inaccurate readings compared to professional meters
  • 🤔 Confusing interface

Audio Function Generator

From 2.2K App Store ratings

What we love

  • 👍 Great app
  • 🎶 Helps with Tinnitus
  • 💯 Best app I've paid for
  • 🔍 Highly recommended
  • 🎨 Attention to detail

Room to improve

  • 🐛 Crashes
  • 💰 Deceptive/Money hungry
  • 🔒 Basic features paywalled
  • 🔒 Limited without paying
  • 🔒 Removed functionality to push paid version

Bugs and requests

Decibel X

Reported bugs

3 issues
  • App crashes when deleting recordings
  • Microphone issues on certain devices
  • Saved files not accessible after updates

Requested features

5 requests
  • Add GPS coordinates to recordings
  • Improve reporting and data export
  • Provide more weighting options
  • Extend frequency range
  • Allow music playback while using the app

Audio Function Generator

Reported bugs

4 issues
  • Crashes on launch
  • Volume slider issues
  • Airplay not working
  • Sound distortion when display is active

Requested features

6 requests
  • Add download/save feature for custom sounds
  • Improve sweep function (continuous mode, better frequency control)
  • Add more multi-frequency rows
  • Implement 432Hz base frequency option
  • Add phase control for noise generators
Show 1 more
  • Improve accessibility (VoiceOver support)

In-app purchases

5 purchases

Decibel X

Subscriptions3
  • Weekly Membership$1.997 Days
  • Monthly Membership$5.991 Month
  • Annual Membership3 Days trial$49.991 Year
One-time2
  • ITU-R 468, A, B, C Weightings$1.99
  • Data Export$2.99
1 purchases

Audio Function Generator

One-time1
  • Upgrade to PRO$9.99

Questions

Is Decibel X free?
Decibel X is free to download, with in-app purchases available.
Is Audio Function Generator free?
Audio Function Generator is free to download, with in-app purchases available.
Which has better reviews, Decibel X or Audio Function Generator?
Audio Function Generator is rated higher. Decibel X averages 4.6 out of 5 from 162K ratings, while Audio Function Generator averages 4.7 from 2.2K ratings.
Do Decibel X or Audio Function Generator have ads?
Neither Decibel X nor Audio Function Generator shows ads.
Which is updated more often, Decibel X or Audio Function Generator?
Decibel X ships an update every 3 months, and Audio Function Generator every 6 weeks. Most recently, Decibel X was updated on September 24, 2026 and Audio Function Generator on September 24, 2026.

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