While creators can now produce text or visuals in an instant, adding authentic music or sound effects to a video is still a slow, manual process. This is a creative bottleneck that Berlin-based startup Mirelo wants to remove.
The company, which has built advanced models capable of generating perfectly timed soundtracks from any video, has raised $41 million in seed funding co-led by Index Ventures and Andreessen Horowitz, with Atlantic.vc and TriplePoint Capital also participating.
The round is one of Europe’s largest early-stage raises in the AI audio space and signals growing investor confidence that sound, long overlooked, is the next frontier in generative media.
Going beyond automatic sound generation
Mirelo was founded in 2023 by CJ Simon-Gabriel and Florian Wenzel, two researchers who met while working at Amazon’s AI labs and shared a frustration with how little attention their field paid to sound. The startup aims to become the audio layer for all visual content, a system that not only saves time but also transforms how audiences experience moving images, from film to video games to social media posts.
“Think of the difference between talkies and silent films – video without sound has so much less feeling and atmosphere. Mirelo’s first step is about democratising access, empowering everyone to create the sound that their (AI) video deserves. But we’ll also empower professionals to rework audio, to do more of what they love, to be more expressive and imaginative in what they can achieve, while handling the boring stuff, such as synchronisation. Our bigger mission is to become the audio layer for all visual content across videos, gaming, social media, films and beyond,” says CJ Simon-Gabriel, CEO and co-founder.
Mirelo’s platform uses its own foundation models for sound generation, trained to understand both what’s happening in a video and the emotional cues it’s intended to convey. When a user uploads footage, the system instantly produces synchronized sound effects or music that align with movement, mood, and pacing.
The models require fifty times less computing power than typical large language systems while delivering superior realism and nuance. The company’s latest release, Mirelo SFX v1.5, can produce multiple variations of a scene’s audio faster than real time, accessible through the Mirelo Studio web app or a developer API.
Mirelo operates in a rapidly developing ecosystem that includes U.S. companies such as ElevenLabs, Boomy, and AudioLDM, which focus on speech or music generation, as well as Kaiber and Runway, which work on integrating audio into video creation. Mirelo distinguishes itself with video-conditioned sound, offering emotional depth and precise synchronisation that others have struggled to achieve.
What’s next?
Mirelo plans to expand its research team and deepen partnerships in gaming, film, and digital storytelling. One major focus is interactive environments, such as adaptive game worlds or dynamic AR spaces, in which real-time sound generation responds to player behaviour.
“Sound is too often an afterthought in video production, yet it’s what determines whether a video or game truly resonates with its audience. Mirelo gives creators a new form of expression, letting them move faster and sound better,” says Georgia Stevenson, the partner at Index Ventures who led the investment.
“Mirelo is tackling one of the most technically challenging and least explored areas of generative media: a specialised model for sound effect creation,” adds Guido Appenzeller, partner at Andreessen Horowitz.
