While doing his master’s degree at UPC, Barcelona, Eloi Moliner noticed an opportunity to do his thesis at Aalto University, which he saw as the best of its kind in Europe when it came to audio processing. He contacted professor Vesa Välimäki to see if he could do 'something' for a few months – then a six-month thesis project turned into four more years of doctoral studies. Now Moliner is returning to Aalto for a post-doctoral position.
Professor Välimäki, leader of the Audio Signal Processing Group, is delighted by the success Moliner has achieved while at Aalto. 'I'm almost tired of writing about all these wins,' he jokes. 'However, Eloi is a truly amazing researcher, who has done groundbreaking work on the use of generative diffusion models in sound processing.'
The awards are, indeed, copious, as during his doctoral studies Moliner has been awarded the following:
We are delighted to keep Moliner for at least a few more years, as the grant proposal written by him and Välimäki passed on the second attempt – now funding Moliner's post-doctoral position, as well as a doctoral student he will be advising.
Eloi Moliner explains his return to AaltoAt Aalto I get to work on projects I really enjoy
For his doctoral thesis, Moliner worked on audio restoration, specifically on using generative models to fill in missing information in recordings: gaps in the signal, missing high frequencies and other issues. While he experimented on various recordings, his focus was on digital versions of historical music circa 1920's and 30's.
'Recordings that old have various distortions and issues. While I can't fully recreate the missing information, I can at least make them sound brighter,' Moliner says.
Working in a research group provided some opportunities for collaboration, but to Moliner it was even more important to be a part of the Aalto Acoustics Lab, which is a wider community comprised of several teams. The lab was a space for academic collaboration, such as getting and providing feedback on research papers. In addition, it was a place to have coffee, discuss work – and play fußball before some afterwork drinks.
During his studies, Moliner travelled across the globe for his internships at top tech companies. The first one took him to the west coast of the USA, where he worked at Microsoft on using generative models to enhance audio – specifically speech.
'As a funny coincidence, my manager there was a researcher who used to be a student at Aalto,' Moliner says.
The second internship was at Sony's headquarters in Japan, this time focusing on music technology and audio mixing. Both of these internships lasted for three months, which Moliner describes as quite intense.
'You have to move along every week and finish something within those three months.'
The third and last research internship was longer, lasting for six months. Moliner was invited to work at Meta, in the company's UK offices. He hadn't planned on this, but was approached by a headhunter looking for students for potential projects.
'These headhunters check conferences and published papers – so it's easier to get an internship once you already have some work under your belt," Moliner explains.
Moliner describes master's studies as structured: you take courses and you pass them, preferably with good grades. Doctoral studies are not like that – instead, you take initiative and work on something that hasn't been properly explored before. 'Sometimes you might not even know what you're doing,' Moliner laughs.
For those considering doctoral studies at Aalto University, Moliner has two tips:
'My first tip is to choose a place where you feel comfortable. Some people like to work in isolation, but I liked working in a lab with a nice community of students and supervisors. Secondly, find a topic you're truly interested in. If you don't have the proper motivation, you might not finish your studies.'
Overall, Moliner recommends taking the leap into doctoral studies. For him, the studies opened a lot of doors and provided opportunities to work on cool things. He muses: 'I don't know what I will end up doing, but it will be more exciting than what I would've done without this degree.'
The International Conference on Digital Audio Effects (DAFx) 2025 witnessed a remarkable achievement by researchers from the Aalto University Acoustics Lab, as Eloi Moliner and Professor Vesa Välimäki brought home two prestigious paper awards, showcasing cutting-edge innovation in audio signal processing.
The award-winning paper shows how speech recordings can be improved by removing the room reverberation effect using unsupervised machine learning
Doctoral education will prepare you for the most demanding expert positions in your field in the academia, companies and public administration. Start here if you’re interested in doctoral studies!
