Selected work

Hemut / Voice research and evaluation

8 kHz speech benchmark

A speech-recognition benchmark built around freight calls, including a scoring correction that changed my model comparison.

0.030.040.050.0602505007501000 msWERMedian latency01020304
Parakeet TDT 0.6B v3170 ms / 0.047 WER

Three reported baselines; one keyterm projection. Local and hosted runtimes differ.

Method & limits

Historical reported summary from open-weight-stt-findings.md, not a fresh run. WER is a fraction; latency is the reported median in milliseconds. Whisper and Parakeet ran locally on an M4 GPU; Deepgram used a hosted API, so timing includes different compute and network conditions, not live-turn latency. The keyterm row is the same Deepgram system: full-corpus WER is projected from seven name clips, and 204 ms is inherited from the baseline, not remeasured. The separate 240-row probe pools six audio conditions and is not this 8 kHz summary.

Match the calls

I built a custom benchmark around the agents' actual domain and use cases: conversational requests, short replies, names, and digits. The corpus uses synthesized audio with telephone-bandwidth and noise conditions. It is not a dataset of customer call recordings.

Revisit the scorer

Seeing issues in Converse made me revisit the scorer. It was penalizing digits written as numerals instead of spoken words. Number-aware scoring changed Parakeet's digit result on the same transcripts; this was a correction to the evaluation, not an improvement to the model.

Test a counterexample

I tried post-hoc snapping, replacing recognized text with nearby directory names, as a counterexample. The naive version made name errors worse in the report. I kept that separate from supplying directory vocabulary during recognition, where the keyterm experiment improved the name-clip result.

A decision for our agents

In my evaluation, replacing the stack with Parakeet would need extra turn detection, and I had concerns about Punjabi accuracy. I considered a hybrid but thought it could be slower and less accurate for our calls. Those are my project-specific judgments, not universal claims about the providers. The benchmark's public repository is pending.

What the evidence says.

measured

Parakeet digit WER after scorer correction

0.303 WERto0.052 WER

Arithmetic means of the stored pk_wer and pk_wer2 scores for the 60 digit rows: 0.302882 and 0.052357. The same transcripts span six audio conditions. This measures a scoring correction, not new recognition performance; the number-aware scorer is not included in the retained probe.

Source
parakeet_bench_results.json: digit-row scores
Sample
10 synthesized digit clips across 6 conditions; 60 paired rows
Recorded
2026-08-05
measured

Paired probe WER across all conditions

0.0486 Deepgram / 0.0537 Parakeet

Arithmetic means of stored dg_wer2 and pk_wer2 scores across all 240 paired rows. The pool includes 16 kHz clean audio, 8 kHz telephony, and four noise levels; it is not the separate 8 kHz summary or a production-call evaluation.

Source
parakeet_bench_results.json: all-condition scores
Sample
40 synthesized clips across 6 conditions; 240 paired rows, each with both model outputs
Recorded
2026-08-05
reported

Name-clip WER with directory keyterms

0.121 WERto0.014 WER

Historical report of the same seven synthesized name clips processed through 8 kHz mu-law audio, with and without directory keyterms. This is a name-subset comparison, not full-corpus WER or measured live-call routing success.

Source
open-weight-stt-findings.md: name-clip comparison
Sample
7 synthesized name clips
Recorded
2026-08-05
projected

Projected full-corpus WER with keyterms

0.050 WERto0.033 WER

The historical report projects the seven-clip name improvement across the full corpus. The accompanying 204 ms latency is inherited from the Deepgram baseline, not a new timing measurement.

Source
open-weight-stt-findings.md: summary table and projection footnote
Sample
40-clip corpus projection from a 7-clip name subset
Recorded
2026-08-05

Benchmark design, voice research, and analysis by DongYeop Lee at Hemut.

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