# Audio Function Generator vs Hydro Calcs

The clearest difference is in-app purchases: Hydro Calcs at none against Audio Function Generator's 1. Hydro Calcs also leads on update cadence (every 5 days vs every 6 weeks). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. Audio Function Generator sells 1 one-off in-app purchase. Hydro Calcs asks for nothing beyond the download.

Audio Function Generator ships an update every 6 weeks, Hydro Calcs every 5 days. The most recent releases landed on October 20, 2026 and October 8, 2026 respectively.

## The numbers

| Metric | Audio Function Generator | Hydro Calcs |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (2.2K ratings)](https://appshunter.io/ios/app/audio-function-generator/id768229610/reviews)** | — |
| Number of ratings | **2.2K** | — |
| Positive reviews | 77.1% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 6 weeks | **Every 5 days** |
| Monetization | Free with in-app purchases | — |
| Size | 13 MB | 2 MB |
| Requires iOS | **16.0** | 17.0 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Thomas Gruber](https://appshunter.io/developer/342699861) | [Milbar](https://appshunter.io/developer/1579581418) |

## What reviewers say

### Audio Function Generator

[App page](https://appshunter.io/ios/app/audio-function-generator/id768229610)

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:** macOS Compatibility, Family Sharing, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Upgrade to PRO | $9.99 | one-time |

**What reviewers like**

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

**What reviewers complain about**

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

**Reported bugs**

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

**Requested features**

- 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


### Hydro Calcs

[App page](https://appshunter.io/ios/app/hydro-calcs/id6817881146)

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

**In-app purchases:** none


## Frequently asked questions

### Is Audio Function Generator free?

Audio Function Generator is free to download, with in-app purchases available.

### Is Hydro Calcs free?

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

### Do Audio Function Generator or Hydro Calcs have ads?

Neither Audio Function Generator nor Hydro Calcs shows ads.

### Which is updated more often, Audio Function Generator or Hydro Calcs?

Audio Function Generator ships an update every 6 weeks, and Hydro Calcs every 5 days. Most recently, Audio Function Generator was updated on October 20, 2026 and Hydro Calcs on October 8, 2026.

---

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