Cathal Lee.Building AdBalloon.
I’m the founder of Upcrossing AI. We’re building AdBalloon to help small businesses make video ads from the photos and information they already have.
AI research · agentic systems · generative speech
Selected work
Current projects and earlier work
in speech and AI engineering.
What I build
I work between model research and product engineering: shaping how AI behaves, designing agentic loops, and turning the useful parts into working software.
Outside work: cello, CrossFit, and cooking.
AI research
I work close to the model, testing ways to steer speech at inference time, guide generation with rewards, and connect audio models to language models.
Agentic building
I build agents as explicit systems: separate roles, private context, review loops, and clear stopping rules that make behaviour easier to inspect and improve.
Product engineering
For AdBalloon, I turn those ideas into a working product with APIs, queues, workers, persistent state, asset pipelines, and video rendering.
Chord
transformations
An interactive example from my
dissertation on group theory and music.
P, L, and R each change one note of a major or minor triad. Choose a transformation, then press Hear chord to listen.
Read the dissertationStart with C major. Choose a transformation.