Tactic — Native macOS App with Per-Device Sound Suppression

What is it

Tactic is a macOS menu-bar app that plays a chosen mechanical-keyboard or mouse sound on every keystroke and click. It's not a UI gimmick — the goal is latency low enough that the synthetic sound feels mechanically attached to your fingers, plus a brutalist editorial UI that doesn't look like every other utility on the Setapp store.

What's interesting under the hood

• Custom AudioToolbox pipeline. Three-buffer AudioQueue at the hardware sample rate, 64-frame buffer (≈1.3ms at 48kHz), Float32 stereo mix via vDSP for zero per-keystroke allocations.
• Per-device suppression (Phase 1, shipped 2026-05-22). IOHIDManager enumerates connected keyboards/mice; a registry layers user toggles on top. When a flagged device is connected, Tactic mutes that input source's sounds. Designed so loud mechanical keyboards don't double-sound when Tactic is on.
• CGEventTap for keyboard, separate listen-only tap for mouse — different TCC permission requirements, which surfaced an interesting failure mode where Secure Input only blocks keyDown/keyUp but lets flagsChanged through.

Status

Phase 1 (per-device mute) is shipped to my daily-driver install. Phase 2 (floating typing visualizer) and Phase 3 (built-in typing test) are queued.

Source is private for now; if you want to try the native build, request access.