AssemblyAI Universal 3.5 Pro vs Speechmatics Linden
Accuracy and speed
Left gets fewer words wrong. Lower has the final text ready sooner.
- Universal 3.5 Pro1.93% · 180ms
- Linden2.46% · 147ms
AssemblyAI Universal 3.5 Pro is ahead on both datasets together, the Pipecat Dataset and time to first text, and Speechmatics Linden on final-text delay. The Ocular Dataset is too close to call. AssemblyAI Universal 3.5 Pro has a newer release: AssemblyAI Universal 3.6 Pro vs Speechmatics Linden.
Last updated Methodology by Dileep Chagam
Who is better at what
- Overall WER2.72%2.97%
- Pipecat Dataset WER1.93%2.46%
- Ocular Dataset WER4.23%3.93%
- Time to first text489ms1.19s
- Final-text delay180ms147ms
Lower is better on every measure. Too close to call means the likely ranges overlap.
Universal 3.5 Pro vs Linden FAQ
Which is more accurate, AssemblyAI Universal 3.5 Pro or Speechmatics Linden?
AssemblyAI Universal 3.5 Pro is more accurate on both datasets. On the 1,000 public Pipecat clips, AssemblyAI Universal 3.5 Pro scores 2.72% and Speechmatics Linden 2.97%, so AssemblyAI Universal 3.5 Pro makes fewer errors by 0.24 points. On the eight licensed Ocular recordings, AssemblyAI Universal 3.5 Pro scores 1.93% and Speechmatics Linden 2.46%, so AssemblyAI Universal 3.5 Pro makes fewer errors by 0.53 points. Word error rate counts incorrect, missing, and extra words, so lower is better.
AssemblyAI Universal 3.5 Pro is more accurate on both datasets. On the 1,000 public Pipecat clips, AssemblyAI Universal 3.5 Pro scores 2.72% and Speechmatics Linden 2.97%, so AssemblyAI Universal 3.5 Pro makes fewer errors by 0.24 points. On the eight licensed Ocular recordings, AssemblyAI Universal 3.5 Pro scores 1.93% and Speechmatics Linden 2.46%, so AssemblyAI Universal 3.5 Pro makes fewer errors by 0.53 points. Word error rate counts incorrect, missing, and extra words, so lower is better.
Yes. AssemblyAI Universal 3.5 Pro finishes the transcript 701ms sooner. AssemblyAI Universal 3.5 Pro has the final transcript 489ms after the speaker stops and Speechmatics Linden 1.19s, at the median. Both are measured on the same 206 streamed turns.
AssemblyAI Universal 3.5 Pro is the stronger pick for voice agents: it makes fewer errors on real conversations and finishes the transcript 701ms sooner. A voice agent cannot reply until the final transcript arrives, and the Ocular recordings are real conversations.
Yes, both return partial text before the speaker stops. AssemblyAI Universal 3.5 Pro shows first text after 4.23% and Speechmatics Linden after 3.93%, at the median.
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