Cartesia Ink 2 vs GPT-4o Mini Transcribe
Cartesia Ink 2 is ahead of GPT-4o Mini Transcribe on the Pipecat Dataset and final-text delay. The Ocular Dataset is too close to call.
Last updated Methodology by Dileep Chagam
Accuracy vs speed
Each dot is one model. Bottom-left is best: fewer errors and a faster final transcript.
Which to pick
Cartesia Ink 2 is the better pick over GPT-4o Mini Transcribe on every measure that separates them: accuracy on clean, scripted audio (0.97 points lower) and quick turn-taking once the caller stops (507ms sooner). For accuracy on real phone conversations, the gap is inside the margin of error, so neither is ahead.
The four metrics, side by side
- Cartesia Ink 2
- 2.39%6th
- GPT-4o Mini Transcribe
- 3.35%11th
Cartesia Ink 2, 0.97 points lower
- Cartesia Ink 2
- 3.09%2nd
- GPT-4o Mini Transcribe
- 4.45%12th
Too close to call: inside the margin of error
- Cartesia Ink 2
- 1.51s11th
- GPT-4o Mini Transcribe
- No text until the speaker stops
Not comparable
- Cartesia Ink 2
- 123ms7th
- GPT-4o Mini Transcribe
- 630ms16th
Cartesia Ink 2, 507ms sooner
Lower is better on every metric. The small figure is each model's place in the whole field. What each metric measures.
- WER · Word error rate
- Share of words the model got wrong: replaced, missing or added. Lower is better.
- Pipecat Dataset
- 1,000 short public clips from Pipecat's STT benchmark dataset.
- Ocular Dataset
- 8 recordings from 4 real phone conversations, licensed from Ocular.
- TTFT · Time to first text
- How long after the audio starts streaming until the first words appear.
- TTFS · Final-text delay
- How long after the caller stops until the full transcript arrives. A voice agent waits for this before it replies.
First text and final text, at three percentiles
Cartesia Ink 2 shows first text after 3.23s and final text after 145ms, and GPT-4o Mini Transcribe shows first text after 40.84s and final text after 1.53s, on a bad turn (P95) across the same streamed turns.
| Measure | Model | P50 | P90 | P95 |
|---|---|---|---|---|
| Time to first text | Cartesia Ink 2 | 1.51s | 2.04s | 3.23s |
| GPT-4o Mini Transcribe | No text until the speaker stops | |||
| Final-text delay | Cartesia Ink 2 | 123ms | 139ms | 145ms |
| GPT-4o Mini Transcribe | 630ms | 1.34s | 1.53s | |
- P50 / P90 / P95 · Typical, slow and slowest turns
- Half of turns are faster than P50. Only 1 in 10 is slower than P90, and 1 in 20 slower than P95.
How each ranks among all 17 models
Place among the 17 models on each metric. Lower is better on all four.
| Metric | Ink 2 | 4o Mini Transcribe |
|---|---|---|
| Pipecat Dataset WER | 2.39%6th of 17 | 3.35%11th of 17 |
| Ocular Dataset WER | 3.09%2nd of 17 | 4.45%12th of 17 |
| Time to first text | 1.51s11th of 15 | Not comparable |
| Final-text delay | 123ms7th of 17 | 630ms16th of 17 |
How much audio each model was tested on
| Model | Pipecat clips | Ocular recordings | Turns timed | Failed |
|---|---|---|---|---|
| Cartesia Ink 2 | 1,000 | 8 | 198 | 0 |
| GPT-4o Mini Transcribe | 1,000 | 8 | 206 | 0 |
Only clips with usable text count, so the two totals can differ. How WER is scored.
Related comparisons
- Cartesia Ink 2 vs Speechmatics Linden
- Cartesia Ink 2 vs Soniox STT-RT v5
- Cartesia Ink 2 vs GPT Realtime Whisper
- Cartesia Ink 2 vs Reson8
- Cartesia Ink 2 vs Inworld STT-1
- Cartesia Ink 2 vs Google Chirp 3
- Cartesia Ink 2 vs AssemblyAI Universal 3.6 Pro
- Cartesia Ink 2 vs Deepgram Nova-3
- Cartesia Ink 2 vs Smallest Pulse
- Cartesia Ink 2 vs GPT-4o Transcribe
- Cartesia Ink 2 vs Deepgram Flux English
- Cartesia Ink 2 vs Deepgram Flux Multilingual
- Cartesia Ink 2 vs Gradium
- GPT-4o Mini Transcribe vs Deepgram Nova-3
- GPT-4o Mini Transcribe vs Smallest Pulse
- GPT-4o Mini Transcribe vs GPT-4o Transcribe
- GPT-4o Mini Transcribe vs Deepgram Flux English
- GPT-4o Mini Transcribe vs Inworld STT-1
- GPT-4o Mini Transcribe vs Soniox STT-RT v5
- GPT-4o Mini Transcribe vs Speechmatics Linden
- GPT-4o Mini Transcribe vs GPT Realtime Whisper
- GPT-4o Mini Transcribe vs Reson8
- GPT-4o Mini Transcribe vs Google Chirp 3
- GPT-4o Mini Transcribe vs AssemblyAI Universal 3.6 Pro
- GPT-4o Mini Transcribe vs Deepgram Flux Multilingual
- GPT-4o Mini Transcribe vs Gradium
Frequently asked questions
Which is more accurate, Cartesia Ink 2 or GPT-4o Mini Transcribe?
Cartesia Ink 2 is more accurate on the public clips. On the 1,000 public Pipecat clips, Cartesia Ink 2 scores 2.39% and GPT-4o Mini Transcribe 3.35%, so Cartesia Ink 2 makes fewer errors by 0.97 points. On the eight licensed Ocular recordings, Cartesia Ink 2 scores 3.09% and GPT-4o Mini Transcribe 4.45%, with likely ranges of 2.43 to 3.84% and 3.22 to 5.55%. The ranges overlap, so the difference is too close to call. Word error rate counts incorrect, missing, and extra words, so lower is better.
Is Cartesia Ink 2 faster than GPT-4o Mini Transcribe?
Yes. Cartesia Ink 2 finishes the transcript 507ms sooner. Cartesia Ink 2 has the final transcript 123ms after the speaker stops and GPT-4o Mini Transcribe 630ms, at the median. Both are measured on the same 206 streamed turns.
Is Cartesia Ink 2 or GPT-4o Mini Transcribe better for voice agents?
Cartesia Ink 2 finishes the transcript 507ms sooner, and the two are too close to call on real conversations. A voice agent cannot reply until the final transcript arrives, and the Ocular recordings are real conversations.
Do Cartesia Ink 2 and GPT-4o Mini Transcribe stream text while the speaker is talking?
Only Cartesia Ink 2. GPT-4o Mini Transcribe returns no text until the speaker stops, which matters if your agent reacts to partial transcripts.