# OTenkeyCalc vs Sound Amplifier +

The clearest difference is update cadence: Sound Amplifier + at every 4 days against OTenkeyCalc's every 2 weeks. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

OTenkeyCalc ships an update every 2 weeks, Sound Amplifier + every 4 days. The most recent releases landed on October 17, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | OTenkeyCalc | Sound Amplifier + |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[3.8 (15 ratings)](https://appshunter.io/ios/app/sound-amplifier-plus/id6782403208/reviews)** |
| Number of ratings | — | **15** |
| Positive reviews | — | 0.0% of reviews |
| In-app purchases | No | No |
| Ads | Yes | Yes |
| Update frequency | Every 2 weeks | **Every 4 days** |
| Monetization | — | Ad-supported |
| Size | 37 MB | 61 MB |
| Requires iOS | 16.7.10 | **16.4** |
| Devices | **iPhone, iPad** | iPhone |
| Age rating | 4+ | 17+ |
| Developer | [Hideaki Uchikoshi](https://appshunter.io/developer/1559575002) | [heekyung moon](https://appshunter.io/developer/6779193748) |

## What reviewers say

### OTenkeyCalc

[App page](https://appshunter.io/ios/app/otenkeycalc/id6502439720)

**Features:** macOS Compatibility

**In-app purchases:** none


### Sound Amplifier +

[App page](https://appshunter.io/ios/app/sound-amplifier-plus/id6782403208)

Enhance your hearing in everyday situations. This tool uses your phone's microphone to amplify nearby sounds and deliver them to your earphones in real time. Adjust sound with an equalizer, reduce background noise, and protect your hearing with a volume limiter.

**Highlights:** Live audio amplification, 3-band equalizer with presets, Speech boost and noise reduction, Left/right balance control, Safe-volume limiter, Offline functionality

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is OTenkeyCalc free?

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

### Is Sound Amplifier + free?

Sound Amplifier + is free to download, with no in-app purchases.

### Do OTenkeyCalc or Sound Amplifier + have ads?

Both OTenkeyCalc and Sound Amplifier + show ads.

### Which is updated more often, OTenkeyCalc or Sound Amplifier +?

OTenkeyCalc ships an update every 2 weeks, and Sound Amplifier + every 4 days. Most recently, OTenkeyCalc was updated on October 17, 2026 and Sound Amplifier + on October 24, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*