Cartesia Ink 2 vs Smallest Pulse
Cartesia Ink 2 is ahead on the Pipecat Dataset, the Ocular Dataset and final-text delay, and Smallest Pulse on time to first text.
Quality and speed frontier
Every model's error rate on the public clips, against how long its transcript takes to settle.
The four metrics, side by side
Word error rate on 1,000 clips from Pipecat's STT benchmark dataset.
- Cartesia Ink 2
- 2.39%5th
- Smallest Pulse
- 3.66%11th
Cartesia Ink 2, 1.27 points lower
Word error rate on eight licensed recordings provided by Ocular.
- Cartesia Ink 2
- 3.09%2nd
- Smallest Pulse
- 3.46%3rd
Cartesia Ink 2, 0.37 points lower
Median delay before the first words arrive, from the first audio packet.
- Cartesia Ink 2
- 1.51s9th
- Smallest Pulse
- 1.06s4th
Smallest Pulse, 454ms sooner
Median delay after the speaker stops before the transcript is final.
- Cartesia Ink 2
- 123ms5th
- Smallest Pulse
- 201ms8th
Cartesia Ink 2, 78ms sooner
Lower is better on every metric. The small figure is each model's place in the whole field.
First text and final text, at three percentiles
Both measured on the same 206 streamed Ocular Dataset turns. P90 and P95 say what a caller meets on a bad turn, which a median hides.
| Measure | Model | P50 | P90 | P95 |
|---|---|---|---|---|
| Time to first text | Cartesia Ink 2 | 1.51s | 2.04s | 3.23s |
| Smallest Pulse | 1.06s | 2.25s | 3.03s | |
| Final-text delay | Cartesia Ink 2 | 123ms | 139ms | 145ms |
| Smallest Pulse | 201ms | 356ms | 773ms |
Both against every other model
Open on the metric where the two sit furthest apart, with the other three a tab away.
Word error rate on 1,000 clips from Pipecat's STT benchmark dataset. Lower is better.
| # | Model | Pipecat Dataset | clips | |
|---|---|---|---|---|
| 1 | AssemblyAI Universal 3.5 Pro | 1.93% | 1,000 | |
| 2 | Google Chirp 3 | 2.00% | 1,000 | |
| 3 | Reson8 | 2.10% | 1,000 | |
| 4 | GPT Realtime Whisper | 2.16% | 1,000 | |
| 5 | Cartesia Ink 2 | 2.39% | 1,000 | |
| 6 | Speechmatics Linden | 2.46% | 998 | |
| 7 | Google Chirp 2 | 2.59% | 1,000 | |
| 8 | Inworld STT-1 | 2.72% | 1,000 | |
| 9 | GPT-4o Mini Transcribe | 3.35% | 1,000 | |
| 10 | Deepgram Nova-3 | 3.46% | 1,000 | |
| 11 | Smallest Pulse | 3.66% | 1,000 | |
| 12 | GPT-4o Transcribe | 3.90% | 1,000 | |
| 13 | Deepgram Flux English | 3.90% | 999 | |
| 14 | Deepgram Flux Multilingual | 4.96% | 999 | |
| 15 | Gradium | 6.48% | 1,000 |
Counts are the clips each model returned usable text for, so they differ between models and between datasets.
Both on the other two views
Pipecat vs Ocular accuracy
Every model's error rate on the public clips, against the same model on real conversations.
Transcription response time
How soon each model returns its first words, against how soon its transcript is final.
What the numbers rest on
| Model | Pipecat clips | Ocular recordings | Turns timed | Failed |
|---|---|---|---|---|
| Cartesia Ink 2 | 1,000 | 8 | 198 | 0 |
| Smallest Pulse | 1,000 | 8 | 206 | 0 |
A clip counts only where the model returned usable text, so counts differ between models. Word error rate is measured the same way throughout: incorrect, missing, and extra words against the reference transcript.
Frequently asked questions
Is Cartesia Ink 2 or Smallest Pulse more accurate?
On the 1,000 public Pipecat clips, Cartesia Ink 2 scores 2.39% and Smallest Pulse 3.66%, so Cartesia Ink 2 makes fewer errors by 1.27 points. On the eight licensed Ocular recordings, Cartesia Ink 2 scores 3.09% and Smallest Pulse 3.46%, so Cartesia Ink 2 makes fewer errors by 0.37 points. Word error rate counts incorrect, missing, and extra words against the reference transcript, so lower is better.
Which is faster, Cartesia Ink 2 or Smallest Pulse?
Smallest Pulse returns first text 454ms sooner, at 1.06s against 1.51s at the median. Cartesia Ink 2 has the final transcript 78ms sooner, 123ms after the speaker stops against 201ms. Both are measured on the same 206 streamed turns.
How were Cartesia Ink 2 and Smallest Pulse compared?
Both ran the same two datasets under the same conditions as every other model in the benchmark: 1,000 public clips from Pipecat's STT benchmark dataset and eight licensed conversation recordings from Ocular. Cartesia Ink 2 returned usable text for 1,000 of the public clips and Smallest Pulse for 1,000. Latency uses each provider's own supported finalization contract.