macOS app Klakk uses pre-loaded PCM buffers and node pools for low-latency typing sounds

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A developer behind the paid macOS app Klakk has detailed the audio architecture used to play low-latency keystroke sound effects on Mac. The design avoids file I/O and format conversion at playback time by pre-loading PCM buffers and completing all processing — including silence trimming and gain calculation — during sound pack initialization. At startup, a fixed pool of 10 AVAudioPlayerNodes is attached to the audio engine, with round-robin selection used to handle overlapping sounds without unlimited audio stacking. If the audio engine stops due to events like an output device change, the app skips playback for that keystroke and restarts cleanly for the next one. The developer notes that achieving low latency was primarily about deciding what not to do after a key is pressed, rather than simply calling faster APIs.

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