How much pre-roll buffer does an energy-gated audio pendant need to stop clipping the first word, and what does it cost in RAM and battery?
research/ambient-preroll
How much pre-roll buffer does an energy-gated audio pendant need to stop clipping the first word? Synthetic audio: no gain in quiet rooms, in the loudest room onset recall 0.866 → 0.980 → 0.999 at 0, 5 and 25 buffered frames (0, 3.1, 15.6 KB) for 90 → 81 → 70 modelled hours; a too-deaf gate is not rescued (stylised)
What it found
A stylised follow-up to ambient-gateroc, which did not measure onset clipping. On synthetic speech over background noise at −60 to −30 dBFS (20 seeds × 120 s per room), a noise-adaptive gate opens on the first frame in quiet rooms, so a pre-roll ring buffer buys nothing and costs battery (82.4 h to 76.9 h at 5 frames). In the loudest room it opens 2.3 frames late on average, and onset recall (first 500 ms of each utterance) goes 0.866, 0.980, 0.999 for 0, 5 and 25 buffered 20 ms frames (0, 3.1, 15.6 KB), at 90.0, 81.1 and 69.7 modelled hours. A gate set too deaf (k = 8) is not rescued: 50 frames lift onset recall only from 0.610 to 0.877. Pre-roll and hangover cost the same per frame and protect different ends of an utterance. Synthetic audio, a stylised power model, no hardware.
A figure from its own output
Paper, code and results
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Produced with AI assistance (Claude). Results are from the code in this repository and are simulated or stylised unless the abstract says otherwise; nothing here implies affiliation with or endorsement by any lab, researcher or company cited. MIT licensed.