# Monad Calendar Clock vs Learn Acoustics Engineering

The clearest difference is update cadence: Monad Calendar Clock at every 6 weeks against Learn Acoustics Engineering's every 31 months. Monad Calendar Clock also leads on price ($0.99 vs $1.99). On ads, in-app purchases, device support and iOS requirement there is nothing between them.

Monad Calendar Clock costs $0.99 and Learn Acoustics Engineering $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Monad Calendar Clock ships an update every 6 weeks, Learn Acoustics Engineering every 31 months. The most recent releases landed on September 6, 2026 and September 7, 2026 respectively.

## The numbers

| Metric | Monad Calendar Clock | Learn Acoustics Engineering |
| --- | --- | --- |
| Price | **$0.99** | $1.99 |
| Rating | **[3.7 (14 ratings)](https://appshunter.io/ios/app/monad-calendar-clock/id1437026437/reviews)** | — |
| Number of ratings | **14** | — |
| Positive reviews | 22.2% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 6 weeks** | Every 31 months |
| Monetization | Paid | — |
| Size | 266 MB | 41 MB |
| Requires iOS | 13.0 | 13.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Earth at the Center LLC](https://appshunter.io/developer/1437026436) | [Muhammad Umair](https://appshunter.io/developer/1696049320) |

## What reviewers say

### Monad Calendar Clock

[App page](https://appshunter.io/ios/app/monad-calendar-clock/id1437026437)

This app visualizes time through planetary and celestial movements, contrasting natural rhythms with mechanical time. It offers unique perspectives on Earth's position in space and time, showing star and planet locations, seasonal changes, and lunar phases.

**Highlights:** Planetary time and date display, Celestial ring visualization, Heliocentric and Geocentric modes, Star and planet location tracking, Seasonal and lunar phase progression, Twilight and sunrise/sunset times, Event scheduling

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

**In-app purchases:** none


### Learn Acoustics Engineering

[App page](https://appshunter.io/ios/app/learn-acoustics-engineering/id6451270819)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Monad Calendar Clock free?

Monad Calendar Clock costs $0.99, with no in-app purchases.

### Is Learn Acoustics Engineering free?

Learn Acoustics Engineering costs $1.99, with no in-app purchases.

### Do Monad Calendar Clock or Learn Acoustics Engineering have ads?

Neither Monad Calendar Clock nor Learn Acoustics Engineering shows ads.

### Which is updated more often, Monad Calendar Clock or Learn Acoustics Engineering?

Monad Calendar Clock ships an update every 6 weeks, and Learn Acoustics Engineering every 31 months. Most recently, Monad Calendar Clock was updated on September 6, 2026 and Learn Acoustics Engineering on September 7, 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.*