Subtle Voicebuds are a private voice interface for computing, in an earbud form factor, that can pick up inaudible whispered speech. Powered by a custom hardware-firmware-software stack and proprietary acoustic machine learning models, Voicebuds isolate the wearer's voice from surrounding noise and capture speech at a whisper, even in extreme noise. Paired with software for iPhone and Mac, Voicebuds enable private dictation in any app, hands-free thought capture, and silent AI chat with responses delivered privately in-ear. Stored notes, transcripts, and chat history are encrypted in transit and at rest, keeping personal content private to the user. The familiar earbud form factor makes voice interactions discreet and natural in open offices, transit, and shared spaces. Voicebuds also function as premium earbuds with music, world-class calls, ANC, and multi-device pairing. Together, the hardware, acoustic models, speech recognition, and software create a private voice computing experience for both loud and quiet spaces.