How can you be tracked though sound?

Discover the world of Ultrasonic Cross-Device Tracking and how it links your devices, enabling advertisers to track behavior and location. Learn where these ultrasonic beacons hide, from TV programs to mobile apps, and find out how well-known brands like McDonald's are involved.


12/6/20232 min read

What is Ultrasonic Cross-Device Tracking?

Ultrasonic cross-device tracking (uXDT) is a method of linking multiple devices of a user to track their behavior and location. It works with all devices equipped with regular speakers or microphones, such as smartphones, tablets, and smart TVs. This technology uses inaudible, high-frequency sounds to connect devices, allowing advertisers to better track users.

Where You Can Find it?

Ultrasonic beacons can be embedded in various forms of media, such as TV programs, websites, online videos, apps on phones, or even digital billboards and banners. Researchers have found hundreds of apps using audio beacons' software development kits, some of which have been downloaded millions of times. Well-known brands like McDonald's and Krispy Kreme have been associated with ultrasonic tracking, but any app that displays advertisements may be exposed to ultrasonic beacons.

How to Prevent Ultrasonic Cross-Device Tracking?

To reduce cross-device tracking, you can take several steps:

1. Limit app permissions: Be cautious when granting apps access to your device's microphone or location data. Only allow access when necessary.

2. Use privacy-focused apps and browsers: Choose apps and browsers that prioritize user privacy and offer features to block or detect ultrasonic tracking.

3. Disable microphone access: For apps that you suspect may be using ultrasonic tracking, disable microphone access to prevent them from receiving ultrasonic signals.

4. Keep devices separate: When possible, keep your devices, such as smartphones and smart TVs, in different rooms or at least a few feet apart to minimize the chances of them being linked through ultrasonic tracking.


Ultrasonic cross-device tracking is a concerning technology that raises privacy concerns. By understanding how it works and taking preventive measures, you can minimize the risk of being tracked without your knowledge. As more users become aware of this technology, it is essential to demand transparency and better privacy protection from companies and developers.

To educate yourself further, read through this sources:

Keep up!

If you find this post interesting and want to protect your Online Privacy & Security even further, subscribe to my newsletter or follow me on X.

Be Sovereign.

Not only online.

Marconius Solidus

Subscribe to my newsletter

You'll also receive FREE E-book, where you will learn how to protect your email against data leaks, spam and unwanted newsletters.