A voice for Cologne – Aristech provides the AI voice for KVB
Cologne's public transport company (KVB) has a new voice – and it comes from Aristech. Together, we developed and integrated the text-to-speech (TTS) solution that will be heard throughout Cologne in the future: in trams, subways, buses, and at stops. The result: a consistent, recognizable voice that combines information and identity.
A voice that sounds like Cologne
Until now, KVB has used different voices in its various modes of transport and systems. Now everything is being brought together: “One voice for Cologne” ensures consistency and reliability – both in everyday situations and in special circumstances.
Aristech was awarded the contract following a public tender and provided technical and technological support for the project from February 2024 onwards. Our language experts evaluated anonymized recordings of female speakers and ultimately recommended Sandra Rosenthal (Radio Cologne) to KVB. Her voice profile combines Rhineland prosody with clear intelligibility—perfect for public spaces and for passengers from all over the world.
From voice to technology
The professional recording of the speaker took place in our Aristech studio. The basic TTS recordings were also made there, which were used to train the AI voice.
The result: a natural-sounding synthesized voice that can generate new announcements in real time based on current timetable data or manual inputs from the control center.
Thorough integration into the KVB system architecture
Our TTS solution was seamlessly integrated into the complex KVB system architecture: The generated announcements are distributed to various playback channels via the computer-aided operations control system (ITCS) and a central data hub – for example, to digital passenger displays (DFI) at stops and to multifunction displays (MFA) in the vehicles.
This leads to:
Uniform announcements across all channels
Real-time synthesis in the event of disruptions, construction sites, and special situations
Bilingual announcements at central stops
High level of robustness even with short-term ad hoc information
This infrastructure creates a networked information chain that optimally complements acoustic and visual systems in line with the two-sense principle. The new voice infrastructure improves the quality of information in everyday use and ensures clear communication in disruptive situations. Information on disruptions and diversions from the control center is distributed system-wide in real time – passengers benefit from clear, understandable, and consistent announcements that create trust.
“Consistency, bilingual availability, and rapid responsiveness improve the information situation in everyday life as well as in the event of incidents,” says Carolin Edler-Mende, co-founder and CEO of Aristech GmbH.
The future of corporate voice
With its new TTS infrastructure, KVB is laying the foundation for a corporate voice strategy that goes beyond local transport. In the future, the uniform voice can also be used for service hotlines, online channels, and social media formats—for recognizable, trustworthy communication at all points of contact.
What began as a technical project has ultimately become a piece of Cologne's identity. Thanks to modern AI language technology, the city now sounds the way it is: open, friendly, understandable – and unmistakably Cologne.
All the facts at a glance
- Project start: February 2024
- Partner: Kölner Verkehrsbetriebe AG (KVB)
- Technology & integration: Aristech GmbH
- Voice: Sandra Rosenthal (Radio Köln)
- Scope: TTS solution, system integration (ITCS, data hub), studio recordings, voice evaluation, and project support