A scientist with an engineering background, I create practical bespoke solutions to complex and demanding problems in audio, acoustics, signals, statistics and data science.

I'm interested in sound; how it is perceived, processed, generated, captured, how it interacts with the physical environment, and how it affects us. Finding answers to these questions, I've gained hands-on experience in a wide range of technologies and methods, from embedded systems and digital signal processing to multivariate time series analysis and data visualization.

I currently work as a freelancer, and I'm always interested to hear about possibilities for collaboration!

Contact

Based in Helsinki, Finland
petteri.hyvarinen@iki.fi
+358 45 636 2330

Skills

Recent projects

Knockout tournament statistics

Are you familiar with the knockout a.k.a single-elimination tournament format in sports? How about using the same idea for pairwise assessment of audio samples?

We analysed the statistical properties of knockout tournaments and showed that these designs could lead to great time savings in prototyping and product development, while not compromising reliability. Similar statistical optimizations might be utilized also in a UX context as an alternative to traditional A/B-testing approaches.

Get the details of the study from the open access pre-print version of the published article from research.aalto.fi

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Interactive map visualization

A side project, where I used d3.js and leaflet.js along with Python's GeoPandas, Shapely, and OCR APIs to create a bespoke visualization of Helsinki's open data on parking violations.

Check out the result (in Finnish) at https://petterihyvarinen.fi/helsinki-parkki

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Mobile app for hearing tests on the field

As part of a research project investigating the acute effects of noise exposure, I implemented a cross-platform app for running hearing experiments on a mobile device. The app was written in NativeScript and Angular to run on both iOS and Android. The app required development of custom plugins for audio, since sound for the hearing tests was generated on-the-fly and adjusted adaptively according to the user's responses.

The app was, and still is, available through App Store, but a pre-registration for the study as well as a in-lab calibration of the device levels are required for using the app. Get in touch if you'd like to try out or know more!

CV

2024- Freelancer First as a side hustle, later full-time. I've worked on projects ranging from bare-metal programming to occupational noise exposure workshop organizing. Combining theoretical knowledge and practical skills, I can tackle difficult problems and provide understandable explanations and useful insights.

In addition to direct contracts, I've also done some small projects via Upwork; have a look at my profile and positive feedback from clients: Upwork

2024-2025 Staff scientist, clinical engineer I worked at the Kuopio University Hospital ENT clinic as a researcher in a large study probing the link between hearing loss and cognitive decline. I was responsible for designing and implementing the EEG submodule of the study, and took part in overall study planning and management. I also worked at the ENT clinic, gaining clinical experience with cochlear implants and ABR measurements.

2019-2024 Postdoctoral researcher Personal funding from Research Council of Finland for a research project on the effects of occupational noise exposure. At the Aalto University Acoustics Lab, I also collaborated in a number of projects in spatial audio, and acted as a co-supervisor in two doctoral projects.

2017-2019 Postdoctoral researcher At the DTU Hearing Systems group in Kgs. Lyngby, Denmark, I worked on research projects relating to tinnitus, hearing aids, EEG, and psychoacoustics, collaborating with the Danish hearing instrument industry. I was a co-supervisor in two doctoral projects and gave a 5 ECTS course in advanced acoustics at SDU.

2012-2017 Doctoral researcher In my doctoral project, I studied electrophysiological methods for diagnosis (MEG) and treatment (tVNS, tDCS) of tinnitus.

2010-2014 Teaching assistant (part-time) I was a teaching assistant for all basic math courses at Aalto University at the so-called math lounge where students could pop in any time and get assistance in their exercise problems.

2011 Research assistant I investigated novel methods for malware detection in the Environmental and Industrial Machine Learning group.

2007-2010 Full-stack software developer (part-time) I was responsible for developing a customer-facing Java -based Liferay portal, working with the full stack from jQuery, HTML and CSS in the front to Java, SQL, and AD user management in the back.

Education & academic titles

Title of docent in the field of technical audiology, Aalto University School of Electrical Engineering

Doctor of Science in Technology (DSc), biomedical engineering and biophysics, Aalto University School of Science

Master of Science in Technology (MSc), acoustics and audio signal processing, Aalto University School of Electrical Engineering