Privacy Policy for Hertzline

Last updated: October 2026

Controller

David Lichters
Maurenbrecherstraße 16
47803 Krefeld
Email: support@lichtersapps.com

In short

Hertzline works without an account and without our own server. Everything you enter stays on your device. We do not collect usage data and use no tracking, advertising or analytics.

Data processed by the app

Hertzline analyzes the microphone signal only while “Listen” is turned on, and only on your device. Only exercises and recordings you choose to save are stored: the audio file, the measured pitch curve and the results (e.g. median in hertz, share within your target range), plus your chosen target. Voice data can be personal, so it only leaves your device if you share or export a recording yourself.

This data is stored only locally in the app’s protected storage on your device. It is not transmitted to us or to third parties. Depending on your device settings it is part of your device backup (iCloud or computer), which Apple or you manage.

Sharing

When you send a document by email, message or the share menu, this happens through the app you choose. You decide on recipients and content. You are responsible for sharing data of third parties (e.g. your customers).

Permissions

Hertzline asks for the microphone the first time you tap “Listen”. Without the microphone the app cannot measure anything. You can revoke the permission anytime in iOS Settings.

Purchases

In-app purchases are handled entirely by Apple. We receive no payment or personal data. Apple’s privacy policy applies: https://www.apple.com/legal/privacy/

Email support

If you email us, we process your address and message only to answer your request (Art. 6(1)(b) and (f) GDPR) and delete them when no longer needed.

Your rights

You have the right to access, rectification, erasure, restriction, data portability and objection (Art. 15-21 GDPR) and the right to lodge a complaint with a supervisory authority. Since your app data stays on your device, you can change, export or delete it there at any time.