Soniox STT-RT v5
Soniox STT-RT v5 is 1st of 17 on final-text delay and 9th of 15 on time to first text.
- 2.54%
- Pipecat WER · 8th
- 3.92%
- Ocular WER · 6th
- 1.20s
- First text · 9th
- 38ms
- Final text · 1st
Quality and speed frontier
Every model's error rate on the public clips, against how long its transcript takes to settle.
Soniox STT-RT v5 against every other model
Open on the metric Soniox STT-RT v5 places highest on, with the other three a tab away. Lower is better on all of them, so the order runs best first.
Final-text delay after the speaker stops. Lower is better.
| # | Model | Final text | turns | |
|---|---|---|---|---|
| 1 | Soniox STT-RT v5 | 38ms | 200 | |
| 2 | Inworld STT-1 | 41ms | 206 | |
| 3 | AssemblyAI Universal 3.6 Pro | 91ms | 206 | |
| 4 | Deepgram Nova-3 | 103ms | 202 | |
| 5 | Deepgram Flux English | 108ms | 199 | |
| 6 | Deepgram Flux Multilingual | 114ms | 175 | |
| 7 | Cartesia Ink 2 | 123ms | 198 | |
| 8 | Speechmatics Linden | 147ms | 194 | |
| 9 | AssemblyAI Universal 3.5 Pro | 180ms | 205 | |
| 10 | Smallest Pulse | 201ms | 206 | |
| 11 | Gradium | 212ms | 198 | |
| 12 | Reson8 | 235ms | 201 | |
| 13 | Google Chirp 3 | 475ms | 206 | |
| 14 | GPT Realtime Whisper | 543ms | 206 | |
| 15 | Google Chirp 2 | 568ms | 205 | |
| 16 | GPT-4o Mini Transcribe | 630ms | 206 | |
| 17 | GPT-4o Transcribe | 652ms | 206 |
Median across the same 206 Ocular Dataset turns. Providers finalize differently, so compare models with similar finalization contracts before treating small gaps as meaningful.
First text and final text, at three percentiles
Measured on the same 206 streamed Ocular Dataset turns as every other model. P90 and P95 say what a caller meets on a bad turn, which a median hides.
| Measure | P50 | P90 | P95 |
|---|---|---|---|
| Time to first text | 1.20s | 1.67s | 1.71s |
| Final-text delay | 38ms | 72ms | 79ms |
Soniox STT-RT v5 on the other two views
The same charts the benchmark page carries, with Soniox STT-RT v5 ringed. Consistency across the two datasets is one reading; how fast a model starts against how fast it commits is the other.
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
- 1,000
- Pipecat clips scored
- 8
- Ocular recordings scored
- 200
- turns timed
- 6
- requests that failed
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.
Soniox STT-RT v5 head to head
- vs AssemblyAI Universal 3.6 Pro
- vs AssemblyAI Universal 3.5 Pro
- vs Google Chirp 3
- vs Reson8
- vs GPT Realtime Whisper
- vs Cartesia Ink 2
- vs Speechmatics Linden
- vs Google Chirp 2
- vs Inworld STT-1
- vs GPT-4o Mini Transcribe
- vs Deepgram Nova-3
- vs Smallest Pulse
- vs GPT-4o Transcribe
- vs Deepgram Flux English
- vs Deepgram Flux Multilingual
- vs Gradium
Frequently asked questions
Where does Soniox STT-RT v5 place in the benchmark?
Soniox STT-RT v5 places highest on final-text delay, 1st of 17 at 38ms. Its weakest placing is time to first text, 9th of 15 at 1.20s.
How accurate is Soniox STT-RT v5?
Soniox STT-RT v5 transcribes the 1,000 public Pipecat clips at 2.54% word error rate and the eight licensed Ocular recordings at 3.92%. Word error rate counts incorrect, missing, and extra words against the reference transcript, so lower is better.
How fast is Soniox STT-RT v5 in a live conversation?
First text arrives after 1.20s at the median, and the transcript is final 38ms after the speaker stops. Both are measured on the same 206 streamed turns as every other model, and the page shows P90 and P95 as well, which is what a caller meets on a bad turn.
How was Soniox STT-RT v5 measured?
Every model runs the same two datasets under the same conditions: 1,000 public clips from Pipecat's STT benchmark dataset for accuracy at scale, and eight licensed conversation recordings from Ocular for real speech. Latency comes from 206 streamed turns, using each provider's own supported finalization contract. Soniox STT-RT v5 returned usable text for 1,000 of the public clips.