About RSJB
RSJB is an independent Brazilian studio building audio and music tools for iPhone, iPad, Mac and Android. We make focused apps that respect the user: fast, no ads, no tracking, one-time purchase.
What we do
Tools made by musicians, for musicians. Each app does one thing well: Rsf2 handles SoundFonts (.sf2), RDX organizes FM synth voices (.syx), Tonic is a full synthesizer (AUv3 and standalone). All handcrafted, focused on the user experience.
Our principles
- ·Processing 100% on-device — the only content that leaves is what you choose to share (for example, publishing to Tonica, in Tonic), always optional.
- ·No ads and no tracking — no analytics SDKs.
- ·No account and no subscription — one-time purchase.
- ·Privacy by design, and respect for the user and the family.
- ·Crafted byte by byte, in Brazil.
The apps
- ·Rsf2 — SoundFont 2 (.sf2) manager: merge, split and edit presets. Live on the App Store.
- ·RDX — .syx voice-cartridge librarian for 6-operator FM synths.
- ·Tonic — AUv3 and standalone synthesizer with 8 sound models (physical modeling, analog, wavetable, SoundFont and FM) and an effects rack.
Platforms
iPhone, iPad and Mac, with Android on the way.
Contact
Reach us at app@rsjb.com.br.