Reviving a 15-year-old binaural beat app on modern Android

joakim@verona.se (Joakim Verona) — Fri, 12 Jun 2026 00:00:00 +0200

About 15 years ago I built an Android binaural beat generator by porting SBaGen (Jim Peters' legendary C program, GPLv2) to native Android via OpenSL ES on an ancient NDK. This summer I thought about how hard could it be to revive it on a modern stack — Kotlin, Jetpack Compose, GitLab CI — expecting the whole thing to be much easier now. It mostly was. But the interesting part was where it wasn't: the platform got more capable and more locked down at the same time.

But first some background if you don't know what binaural beats are. The brain has different states you can measure as different frequencies (EEG bands), associated with modes like sleep or wakefulness. That part isn't controversial. The idea of binaural beats is that you can induce one of those states by playing two slightly different frequencies, one in each ear — the difference between them being the target brain-state frequency. Whether that entrainment actually works is the more dubious, mumbo-jumbo-adjacent claim.

For me some of the frequencies appear to work which is good enough for me, and I also like drone music like Eliane Radigue, and the sounds of this app are to me similar.

Anyway, on to the technical discussion.

Kotlin on Joakim Verona

Reviving a 15-year-old binaural beat app on modern Android