Comparison

SimpleFFT vs Contour Detection

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

Head to head

Frequency analysis

About

SimpleFFT

Features

Read full description

This app can easily analyze the frequency of sound. For the sound of the recording file recorded at each refresh time interval, FFT is executed and displayed for the four voices collected one after another at each refresh interval.

About

Contour Detection

Features

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Detects the contours of the edges of an image.

Screenshots

SimpleFFT4 screens

Contour Detection2 screens

Verdict

The call

The clearest difference is in-app purchases: Contour Detection at none against SimpleFFT's 1. Contour Detection also leads on update cadence (fortnightly vs every 18 months). SimpleFFT's advantage is device support (3 vs 1) and iOS requirement (15.0 vs 17.7.2). On price 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

Both are free to download. SimpleFFT sells 1 one-off in-app purchase. Contour Detection asks for nothing beyond the download.

UpkeepUpdate frequency

SimpleFFT ships an update every 18 months, Contour Detection fortnightly. The most recent releases landed on October 10, 2026 and September 30, 2026 respectively.

Scorecard4 real differences · 2 level

SimpleFFT versus Contour Detection: the parameters behind the verdict, then further details
Parameter	SimpleFFT	Contour Detection
Price	Free	Free
Update frequency	Every 18 months	Fortnightly — better
Ads	Yes	Yes
In-app purchases	Yes	No — better
Devices	iPhone, iPad, iPod — better	iPhone
Requires iOS	15.0 — better	17.7.2
Further details — not scored
Size	5 MB	36 MB
Age rating	4+	4+
Developer	HIROFUMI MARUO	Hideaki Uchikoshi

In-app purchases

1 purchases

SimpleFFT

One-time1

Premium Functions$0.49

None

Contour Detection

No in-app purchases

Questions

Is SimpleFFT free?

SimpleFFT is free to download, with in-app purchases available.

Is Contour Detection free?

Contour Detection is free to download, with no in-app purchases.

Do SimpleFFT or Contour Detection have ads?

Both SimpleFFT and Contour Detection show ads.

Which is updated more often, SimpleFFT or Contour Detection?

SimpleFFT ships an update every 18 months, and Contour Detection fortnightly. Most recently, SimpleFFT was updated on October 10, 2026 and Contour Detection on September 30, 2026.