Deepgram Flux Multilingual is ahead on the Pipecat Dataset, time to first text and final-text delay, and Gradium on the Ocular Dataset.
Every model's error rate on the public clips, against how long its transcript takes to settle.
Word error rate on 1,000 clips from Pipecat's STT benchmark dataset.
Deepgram Flux Multilingual, 1.52 points lower
Word error rate on eight licensed recordings provided by Ocular.
Gradium, 0.08 points lower
Median delay before the first words arrive, from the first audio packet.
Deepgram Flux Multilingual, 912ms sooner
Median delay after the speaker stops before the transcript is final.
Deepgram Flux Multilingual, 98ms sooner
Lower is better on every metric. The small figure is each model's place in the whole field.
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 | Deepgram Flux Multilingual | 793ms | 2.00s | 3.41s |
| Gradium | 1.71s | 4.05s | 7.32s | |
| Final-text delay | Deepgram Flux Multilingual | 114ms | 135ms | 141ms |
| Gradium | 212ms | 266ms | 280ms |
Open on the metric where the two sit furthest apart, with the other three a tab away.
Time to first text, measured from the first audio packet. Lower is better.
| # | Model | First text | turns | |
|---|---|---|---|---|
| 1 | AssemblyAI Universal 3.5 Pro | 489ms | 205 | |
| 2 | Deepgram Flux English | 791ms | 199 | |
| 3 | Deepgram Flux Multilingual | 793ms | 175 | |
| 4 | Smallest Pulse | 1057ms | 206 | |
| 5 | Inworld STT-1 | 1063ms | 206 | |
| 6 | Deepgram Nova-3 | 1064ms | 203 | |
| 7 | Speechmatics Linden | 1190ms | 194 | |
| 8 | GPT Realtime Whisper | 1379ms | 206 | |
| 9 | Cartesia Ink 2 | 1511ms | 198 | |
| 10 | Gradium | 1705ms | 198 | |
| 11 | Reson8 | 2400ms | 201 | |
| 12 | Google Chirp 3 | 4480ms | 206 | |
| 13 | Google Chirp 2 | 4497ms | 205 |
Not ranked: GPT-4o Mini Transcribe and GPT-4o Transcribe return no text until the speaker stops, so first-text time is not comparable.
Median across the same 206 Ocular Dataset turns. Providers finalize differently, so compare models with similar finalization contracts before treating small gaps as meaningful.
Every model's error rate on the public clips, against the same model on real conversations.
How soon each model returns its first words, against how soon its transcript is final.
| Model | Pipecat clips | Ocular recordings | Turns timed | Failed |
|---|---|---|---|---|
| Deepgram Flux Multilingual | 999 | 8 | 175 | 31 |
| Gradium | 1,000 | 8 | 198 | 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.
On the 1,000 public Pipecat clips, Deepgram Flux Multilingual scores 4.96% and Gradium 6.48%, so Deepgram Flux Multilingual makes fewer errors by 1.52 points. On the eight licensed Ocular recordings, Deepgram Flux Multilingual scores 4.53% and Gradium 4.45%, so Gradium makes fewer errors by 0.08 points. The two datasets disagree, so the better choice depends on whether your audio looks more like clean public clips or real conversations.
Deepgram Flux Multilingual returns first text 912ms sooner, at 793ms against 1.71s at the median. Deepgram Flux Multilingual has the final transcript 98ms sooner, 114ms after the speaker stops against 212ms. Both are measured on the same 206 streamed turns.
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. Deepgram Flux Multilingual returned usable text for 999 of the public clips and Gradium for 1,000. Latency uses each provider's own supported finalization contract.