SimpleFFT vs Ka
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
SimpleFFT
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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.
Ka
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Ka-ching SecondScreen provides the opportunity of a customer-facing screen in-store when using Ka-ching POS. Registration of products and discounts will be visible to the customer on the screen. In case of signing a membership, customers will be able to apply their e-mail addresses themselves.
Screenshots
Verdict
The clearest difference is in-app purchases: Ka at none against SimpleFFT's 1. Ka also leads on ads (none vs shown) and update cadence (every 2 months vs every 18 months). On price, device support and iOS requirement 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
Both are free to download. SimpleFFT sells 1 one-off in-app purchase. Ka asks for nothing beyond the download.
SimpleFFT ships an update every 18 months, Ka every 2 months. The most recent releases landed on October 10, 2026 and October 3, 2026 respectively.
| Parameter | SimpleFFT | Ka |
|---|---|---|
| Price | Free | Free |
| Update frequency | Every 18 months | Every 2 months — better |
| Ads | Yes | No — better |
| In-app purchases | Yes | No — better |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 15.0 — better | 16.0 |
| Further details — not scored | ||
| Size | 5 MB | 30 MB |
| Age rating | 4+ | 4+ |
| Developer | HIROFUMI MARUO | Ka-ching ApS |
In-app purchases
SimpleFFT
- Premium Functions$0.49
Ka
No in-app purchases
