The audience for this is Home Assistant users, who are not necessarily developers. The instructions assumed too much and buried the step most likely to trip someone up. Biggest fix: connecting to Home Assistant is two steps, not one. Adding the Wyoming integration does nothing on its own -- the assistant keeps using whatever speech-to-text it used before until you change it under Settings -> Voice assistants. That was previously half a sentence at the end of a paragraph, and its failure mode is silent: everything looks installed and nothing improves. It is now its own numbered step with an explanation. Also adds: - "Check it's working" and "Troubleshooting", the latter drawn from failures actually hit while building and deploying this, including the wrong-Python error and the service-did-not-start-after-changing-user case. - IP address guidance that survives contact with a real machine. Checking on the deployment host showed five addresses -- two Parallels interfaces, a Tailscale one, and two real ones -- so the docs now say which to ignore. The obvious `ipconfig getifaddr en0` was rejected: it returns nothing there. - Requirements now lead with `brew install python@3.13` rather than an explanation of lzma; the reasoning moved into a collapsed block. - A plain-English guide to reading the benchmark table, and an explicit note that the numbers are a snapshot nothing re-runs automatically. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
165 lines
8.2 KiB
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165 lines
8.2 KiB
Markdown
<!-- Numbers here are reproduced by bench/benchmark.py; see Reproducing below. -->
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# Benchmarks
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All figures measured on one machine: **M4 Mac mini (10-core, 32 GB), macOS 26.5**.
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48 clips — 16 Home Assistant commands rendered through three macOS TTS voices
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(Daniel, Samantha, Karen). Every backend loads once, transcribes all 48 clips
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to warm up, then runs a timed pass. Latency is the **median** of that pass;
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means are skewed by first-request kernel compilation.
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| Backend | Runtime | Median | p90 | Exact | Digits | Silence |
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|---|---|--:|--:|--:|--:|---|
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| moonshine tiny | ONNX CPU | 28 ms | 44 ms | 31/48 | 15/21 | `""` |
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| moonshine base | ONNX CPU | 53 ms | 70 ms | 35/48 | 20/21 | `""` |
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| **parakeet-tdt-0.6b-v2** | **MLX** | **102 ms** | **112 ms** | **46/48** | **21/21** | `""` |
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| parakeet-tdt-0.6b-v3 | MLX | 128 ms | 149 ms | 36/48 | 10/21 | `""` |
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| faster-whisper tiny.en | CPU int8 | 182 ms | 204 ms | 44/48 | 21/21 | `"you"` |
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| faster-whisper base.en | CPU int8 | 326 ms | 347 ms | 44/48 | 19/21 | `"you"` |
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| whisper.cpp large-v3-turbo | Metal + CoreML | 518 ms | 537 ms | 47/48 | 21/21 | `"thank you"` |
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| mlx-whisper large-v3-turbo | MLX | 828 ms | 848 ms | 47/48 | 21/21 | `"thank you"` |
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| whisper.cpp large-v3 | Metal + CoreML | 941 ms | 1042 ms | 47/48 | 21/21 | `"thank you"` |
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| faster-whisper small.en | CPU int8 | 974 ms | 1032 ms | 47/48 | 21/21 | `"you"` |
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| mlx-whisper large-v3 | MLX | 1170 ms | 1251 ms | 48/48 | 21/21 | `"thank you"` |
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| faster-whisper distil-large-v3 | CPU int8 | 4269 ms | 4304 ms | 46/48 | 21/21 | `"thank you"` |
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### How to read this
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- **Median** — the typical time to transcribe one command. This is the number
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you feel when talking to your assistant.
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- **p90** — nine times out of ten it was at least this fast. A p90 close to the
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median means consistent; a long tail is worse than the median suggests.
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- **Exact** — how many of the 48 clips came back word-for-word correct.
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- **Digits** — of the 21 clips containing a number, how many wrote it as `21`
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rather than `twenty one`. This matters more than it looks; see
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[Model choice](README.md#model-choice-v2-not-v3).
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- **Silence** — what came back for three seconds of pure silence. Anything
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other than nothing is the model inventing words, which your assistant then
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tries to act on.
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**Exact** is a strict string match after normalising case, punctuation and
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whitespace. **Digits** counts how many of the 21 number-bearing clips came
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back with digits rather than spelled-out words — see
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[Model choice](README.md#model-choice-v2-not-v3) for why that matters more than it looks.
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**Silence** is the output for three seconds of digital silence.
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What the numbers say:
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- **Parakeet v2 has the best latency/accuracy trade-off here.** It is 5×
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faster than the best whisper.cpp configuration and lands within one clip of
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it on accuracy.
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- **`mlx-whisper large-v3` is the accuracy ceiling** — the only backend to
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score 48/48 — but costs 11× the latency to get there.
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- **Moonshine is genuinely faster**, at 2× Parakeet's speed, and it also
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handles silence cleanly. It gives up real accuracy for it (35/48), so it is
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the right pick only if latency dominates everything else.
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- **Parakeet v3's 10/21 on digits** is the ITN problem quantified. Its exact
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match (36/48) is dragged down almost entirely by that one behaviour.
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- Both clips Parakeet v2 misses are the same word — "aircon", which the TTS
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voices render as "air con" / "aircan". Accuracy differences at the top of
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this table are concentrated in a couple of awkward tokens, not spread out.
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## Caveats — read these before trusting the table
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- **This is not a WER benchmark.** The audio is clean synthetic TTS from three
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similar English voices, with no noise, accents, crosstalk or far-field
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effects. It measures latency rigorously and accuracy only as a domain smoke
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test. For real word error rates see the
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[Open ASR Leaderboard](https://huggingface.co/spaces/hf-audio/open_asr_leaderboard).
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- **faster-whisper is CPU-only on Apple Silicon.** CTranslate2 has no Metal
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backend, so those rows show CPU int8 performance. On an NVIDIA GPU they
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would look completely different — do not read this as a verdict on
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faster-whisper generally, only on what it does on this hardware.
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- **Latency is raw inference**, excluding Wyoming protocol overhead. End to
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end through this server, expect roughly 15–35 ms on top.
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- One machine, one run each. Treat differences of a few percent as noise.
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- **These are a point-in-time snapshot.** Nothing re-runs them automatically,
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and the test suite cannot detect drift, so treat them as stale after any
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change to the audio path, a `parakeet-mlx`/MLX upgrade, or a macOS release
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(which changes the TTS voices the clips are built from). Re-run the sweep
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and update the table in the same commit as the change.
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## Reproducing
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**1. Set up a throwaway venv.** Keep the benchmark dependencies out of the
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service venv — they pull in CTranslate2, ONNX Runtime and a second copy of
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MLX, none of which the server needs:
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```bash
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python3.13 -m venv /tmp/bench-venv # explicit version, not bare python3
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/tmp/bench-venv/bin/pip install -r bench/requirements.txt
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```
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Use an explicit interpreter, not bare `python3` — on macOS that is still the
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system Python 3.9, which has no MLX wheels and fails with
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`No matching distribution found for parakeet-mlx`. Homebrew's
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`python3.11`/`3.12`/`3.13`/`3.14` all work.
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**2. Render the clips** (macOS only — it uses the built-in `say` voices):
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```bash
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./bench/make_clips.sh
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```
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Writes 49 files to `bench/clips/` (16 phrases × 3 voices, plus silence). They
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are gitignored; regenerating them is deterministic for a given macOS release,
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but voice quality does change between releases, so numbers are only strictly
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comparable within one machine.
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**3. Run a backend.** The `--backend` argument is `kind:model`:
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```bash
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/tmp/bench-venv/bin/python bench/benchmark.py \
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--backend parakeet:mlx-community/parakeet-tdt-0.6b-v2
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```
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Add `--json` for a single machine-readable line instead of the human report,
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and `--label` to control the name in the output. Without `--json` it also
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prints every mismatch with expected-vs-actual, which is the useful bit when a
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model scores worse than you expected.
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If you have `HF_HUB_OFFLINE=1` exported (the service sets it), prefix the
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command with `HF_HUB_OFFLINE=` so it can fetch models it has not seen.
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**The exact commands behind each table row:**
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| Row | Command |
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|---|---|
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| moonshine tiny | `--backend moonshine:moonshine/tiny` |
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| moonshine base | `--backend moonshine:moonshine/base` |
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| parakeet-tdt-0.6b-v2 | `--backend parakeet:mlx-community/parakeet-tdt-0.6b-v2` |
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| parakeet-tdt-0.6b-v3 | `--backend parakeet:mlx-community/parakeet-tdt-0.6b-v3` |
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| faster-whisper tiny.en | `--backend faster-whisper:tiny.en` |
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| faster-whisper base.en | `--backend faster-whisper:base.en` |
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| faster-whisper small.en | `--backend faster-whisper:small.en` |
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| faster-whisper distil-large-v3 | `--backend faster-whisper:distil-large-v3` |
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| mlx-whisper large-v3-turbo | `--backend mlx-whisper:mlx-community/whisper-large-v3-turbo` |
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| mlx-whisper large-v3 | `--backend mlx-whisper:mlx-community/whisper-large-v3-mlx` |
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| whisper.cpp \* | `--backend whispercpp:http://127.0.0.1:8920/inference` |
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\* The whisper.cpp rows need a server running first. That requires your own
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[whisper.cpp](https://github.com/ggml-org/whisper.cpp) build — ideally with
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`-DWHISPER_COREML=1` for the CoreML encoder, which is what the table
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measured:
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```bash
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./build/bin/whisper-server -m models/ggml-large-v3-turbo.bin \
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--host 127.0.0.1 --port 8920 -nc -sns -l en -t 4
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```
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`-nc` matters. Without it the server carries decoder context between requests
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and periodically returns the previous utterance, which would make whisper.cpp
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look far worse than it is. The table gives it its best configuration
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deliberately.
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**Cost.** The full sweep is roughly 15 minutes of compute, dominated by
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`distil-large-v3` at ~4.3 s per clip, plus however long it takes to pull about
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7 GB of models. To clean up afterwards:
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```bash
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rm -rf /tmp/bench-venv bench/clips
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rm -rf ~/.cache/huggingface/hub/models--mlx-community--whisper-large-v3*
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rm -rf ~/.cache/huggingface/hub/models--Systran--faster-*
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rm -rf ~/.cache/huggingface/hub/models--UsefulSensors--moonshine*
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```
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