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qwen_asr has no quantized-weights option, so the only lever available to reduce the 1.7B model's memory footprint is avoiding concurrent instances. Previously each track (system, mic) ran its own transcribeTrack goroutine with independent qwen_asr subprocesses, so simultaneous speech on both tracks meant two ~6.9GiB model instances alive at once - over half the 24GB target machine's memory. Merge both tracks onto a single worker (asrSegs channel, dispatch() routes both tracks onto it) so invocations are strictly serialized; per-track order is preserved since VAD's output is already chronological. Verified via pgrep -x qwen_asr polling during a real dual-track capture: never more than 1 concurrent process. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>