How GPS-Triggered Audio Commentary Works on a Tour Bus

A sightseeing bus passes the cathedral, and forty passengers hear about it at the same moment, each in their own language. No guide pressed a button. Here's what is happening behind the scenes, and what to look for when you choose an audio commentary system for your fleet.

1. Every stop is a geofence

Each point of interest on your route gets a trigger radius: an invisible circle on the map. When a passenger's phone detects that the bus has entered the circle, that stop's commentary starts.

Getting the radius right matters:

• Too small, and a bus moving at speed can skip right over it between two GPS readings.
• Too large, and commentary starts before passengers can see what's being described.

Good systems don't just check "am I inside the circle now?". They also look at the path between the previous location and the current one, so a fast-moving bus can't jump over a stop.

2. Direction cones stop the wrong story playing

Many routes pass the same street twice, once in each direction. A bearing cone tells the system to trigger a stop only when the vehicle is heading the right way, so "on your left" is actually on the left.

3. Audio has to survive a locked screen

A tour can last two or three hours. Passengers lock their phones, put them in a pocket and look out of the window. Commentary needs to keep running regardless, which requires background location and background audio. Native apps can do this reliably on both iOS and Android; mobile browsers generally pause or throttle a page once the screen locks, which is why TourChorus uses an app.

4. Languages are content, not an afterthought

Multilingual commentary means every stop has a script, a translation and an audio file per language. In practice the work is:

1. Write (or AI-draft) the script in your main language.
2. Translate it into each language you offer.
3. Record or generate a voiceover for each translation.
4. Check that each version fits the time it takes to drive to the next stop.

Keeping all of this in one place, with a clear view of which language is missing what, is the difference between a tour you update every season and one that never changes.

5. Test the route before passengers do

The best time to discover a pin is on the wrong side of the road is before your first departure. A route dry run simulates the drive along real roads and reports any stop that wouldn't trigger.

Putting it together

GPS-triggered commentary isn't magic: it's geofences, direction checks, background audio and well-organised multilingual content. TourChorus bundles all of it, from the map editor to AI translation and voiceover to a rider app that carries your brand.

See how TourChorus works, or try the live Lady Dive demo on your phone.