# Sub System vs TutorLog

The clearest difference is price: TutorLog at Free against Sub System's $30.00. Sub System's advantage is in-app purchases (none vs 2) and update cadence (every 10 days vs every 2 months). On review sentiment, ads and device support there is nothing between them.

TutorLog is free to download; Sub System costs $30.00 up front. TutorLog sells 2 in-app purchases, starting at $2.99 per month. Sub System asks for nothing beyond the download.

Sub System ships an update every 10 days, TutorLog every 2 months. The most recent releases landed on October 7, 2026 and October 12, 2026 respectively.

## The numbers

| Metric | Sub System | TutorLog |
| --- | --- | --- |
| Price | $30.00 | **Free** |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 10 days** | Every 2 months |
| Monetization | Paid | **Freemium** |
| Size | 48 MB | 5 MB |
| Requires iOS | **13.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [sebastian rivas](https://appshunter.io/developer/506708461) | [慧慧 高](https://appshunter.io/developer/1887721875) |

## What reviewers say

### Sub System

[App page](https://appshunter.io/ios/app/sub-system/id1533524994)

This app allows audio engineers and sound designers to visualize sound pressure levels and their interactions. Users can place virtual speakers and microphones, manipulate them with touch gestures, and observe colorful graphs of SPL and frequency response to understand acoustical summation.

**Highlights:** Virtual speaker placement, Sound pressure level visualization, Frequency response graphs, Virtual microphone simulation, Touch-based manipulation, Acoustical summation understanding

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

**In-app purchases:** none


### TutorLog

[App page](https://appshunter.io/ios/app/tutorlog-tutor-lesson-tracker/id6763914691)

This app helps private tutors manage student progress, lesson notes, schedules, and payments. It allows for detailed session logging, progress tracking, and generating parent-ready reports. All data is stored locally for privacy.

**Highlights:** Log session details (date, duration, topics, homework), Track student progress and goals, Manage schedules and payments, Generate parent-ready progress reports, Local data storage for privacy, Calendar and statistics view

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Monthly | $2.99 | per month |
| Pro Annual | $19.99 | per year |


## Frequently asked questions

### Is Sub System free?

Sub System costs $30.00, with no in-app purchases.

### Is TutorLog free?

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

### Do Sub System or TutorLog have ads?

Neither Sub System nor TutorLog shows ads.

### Which is updated more often, Sub System or TutorLog?

Sub System ships an update every 10 days, and TutorLog every 2 months. Most recently, Sub System was updated on October 7, 2026 and TutorLog on October 12, 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.*