Comparison

Voice Spectrogram Logger vs Mandel Draw

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

Head to head
About

Voice Spectrogram Logger

Visualize voice frequencies in a spectrogram from 20-2500Hz. Adjust display with sliders and log recordings to export as PNG files. Functions fully offline and supports background processing.

Highlights
  • Real-time voice spectrogram display
  • Adjustable frequency range (20-2500Hz)
  • Zoomable spectrogram with pinch gestures
  • Customizable spectrogram gradation
  • Logging mode with history export
  • Offline functionality
Features
Read full description

1. DESPLAY The spectrogram of voice is displayed in the range of 20 - 2500Hz. You can zoom in/out the spectrogram by pinching in/out smoothly. Also landscape orientation is supported. 2. USEFUL By moving "vivid" slider, the gradation of spectrogram is controlled. The gradation is also controlled by moving "baseline" slider in "Setting" tab and selecting "Mean" or "RMS" as the way of smoothing the spectrogram out. 3. LOGGING When "log" switch is ON, this app runs in the logging mode. To choose a past log from "History" tab, you can pull it from iPhone via email as a PNG file. 4. AVAILABLE Without cellular data service, the full functions are available. The background processing is supported. 5. TECHNICAL NOTE Sample rate: 44.1kHz Bit depth: 32bit float FFT window function: Blackman FFT samples: 4096

About

Mandel Draw

Explore the infinite beauty of fractals with this intuitive drawing app. Generate Mandelbrot and Julia sets with numerous functions and color palettes. Enjoy simple touch controls for navigation and advanced settings for high-resolution output and iCloud syncing.

Highlights
  • Mandelbrot and Julia set generation
  • 80+ fractal functions
  • 20+ color palettes
  • Intuitive touch controls (drag, pinch, tap)
  • High-resolution output
  • iCloud Sync for favorites and palettes
Features
Read full description

Mandel Draw is an application that allows you to enjoy fractals, Mandelbrot sets and filled Julia sets, in a fast and comfortable way. The app allows you to draw an infinite number of fractal images from up to 80 different functions, 20+α color palettes, and freely configurable Julia parameters. Operation is simple. Drag to move, pinch to zoom in and out. Double- and triple-tap operations are also available. Convenient settings are also available. - Use DF64 operation: Double the float operation to make it possible to zoom in more. (Disabled in the Appendix 1,2) - Select render version: Two types of rendering methods can be selected. - Display coordinates and magnification: The current coordinates and magnification will be displayed on the screen. - Output detailed information: Add detailed information to the text when sharing. - High-resolution output: Outputs at 4 times the vertical and horizontal resolution when sharing. - iCloud Sync: Share favorites and My Palette with another iPhone or iPad. In addition, all functions are available when unlocked with in-app purchase. 1) All functions are selectable 2) All palettes can be selected 3) Up to 2000 favorites can be saved 4) Maximum number of My Palettes that can be saved is now 30. Now, please enjoy the wonderful and mysterious world of fractals. What is a fractal? Simply put, a fractal is a self-similar figure that does not lose its complexity no matter how much it is enlarged. (Though computers have their limitations.) There are various fractal shapes, such as the Koch curve, Sierpinski's gasket, and Menger's sponge. The Mandelbrot set and the filled Julia set are fractals drawn computationally on the complex plane.

Screenshots

Voice Spectrogram Logger4 screens
Mandel Draw4 screens

Verdict

The call

The clearest difference is review sentiment: Mandel Draw at 53% against Voice Spectrogram Logger's 0%. Mandel Draw also leads on rating (4.5 vs 1.0) and update cadence (weekly vs every 15 months). Voice Spectrogram Logger's advantage is monetization model (free vs free with in-app purchases). On price, ads, in-app purchases 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

Both are free to download. Voice Spectrogram Logger sells 1 one-off in-app purchase and Mandel Draw 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

Mandel Draw holds the better App Store score, 4.5 against 1.0. That said, the two scores are not equally well evidenced: Mandel Draw has 147 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 0% of Voice Spectrogram Logger's written reviews are positive against 53% of Mandel Draw's.

UpkeepUpdate frequency

Voice Spectrogram Logger ships an update every 15 months, Mandel Draw weekly. The most recent releases landed on October 2, 2026 and October 14, 2026 respectively.

Scorecard5 real differences · 5 level
Voice Spectrogram Logger versus Mandel Draw: the parameters behind the verdict, then further details
ParameterVoice Spectrogram LoggerMandel Draw
PriceFreeFree
Rating1.0 (1 ratings)4.5 (147 ratings) — better
Positive reviews0.0% of reviews53.3% of reviews — better
Number of ratings1147 — better
Update frequencyEvery 15 monthsWeekly — better
AdsNoNo
In-app purchasesYesYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.5 — better16.0
Further details — not scored
Size7 MB22 MB
Age rating12+4+
DeveloperYukiko IwaiKouji Mori

Customer experience

Voice Spectrogram Logger

All ratings1 ratings
Positive0.0%
Neutral0.0%
Negative100.0%
Written reviews1 reviews
Positive0.0%
Neutral0.0%
Negative100.0%

Mandel Draw

All ratings147 ratings
Positive87.1%
Neutral4.8%
Negative8.2%
Written reviews30 reviews
Positive53.3%
Neutral20.0%
Negative26.7%

In-app purchases

1 purchases

Voice Spectrogram Logger

One-time1
  • Remove Ads$3.99
1 purchases

Mandel Draw

One-time1
  • Unlock$1.99

Questions

Is Voice Spectrogram Logger free?
Voice Spectrogram Logger is free to download, with in-app purchases available.
Is Mandel Draw free?
Mandel Draw is free to download, with in-app purchases available.
Which has better reviews, Voice Spectrogram Logger or Mandel Draw?
Mandel Draw is rated higher. Voice Spectrogram Logger averages 1.0 out of 5 from 1 ratings, while Mandel Draw averages 4.5 from 147 ratings.
Do Voice Spectrogram Logger or Mandel Draw have ads?
Neither Voice Spectrogram Logger nor Mandel Draw shows ads.
Which is updated more often, Voice Spectrogram Logger or Mandel Draw?
Voice Spectrogram Logger ships an update every 15 months, and Mandel Draw weekly. Most recently, Voice Spectrogram Logger was updated on October 2, 2026 and Mandel Draw on October 14, 2026.

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