Phonon-2 is a 164 MB speech recognition model that matches the accuracy of a much larger teacher model while being 15 times smaller. It averages 5.21% word error across seven English test sets and runs extremely fast—transcribing an hour of audio in 20 seconds on a MacBook Air.

• Achieves 5.21% average word error rate across Open ASR Leaderboard benchmarks, beating larger models including Whisper large-v3-turbo (6.58%) and matching its 2.5 GB teacher model's accuracy despite being 1/15th the size
• Extreme speed: processes audio 174x faster than realtime on M5 MacBook Air, 143x on Zen 5 CPU, and 6,680x on H100 GPU in batches
• Quantized to 2.1 bits per weight using five learned levels, enabling the tiny download size while maintaining teacher-model performance