← Text-to-Speech

Soniox

tts-rt-v1

Measured 2026-07-03

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tts-rt-v1 is measured here for comparison — it is not one of the models Speko routes.

Naturalness

1569

Win % · 95% CI

63%

56–69%

Drift

24

Synth p50

362ms

362–388 p50–p90

Robustness

0.35

Fined:

• fatal · currency — dropped the minus sign (4 of 7 transcripts)

→ we sent “A refund of -$0.99 was applied.”

→ it said “A refund of $9.99 was applied.”

• fatal · dates — never said “sunday” (40 of 43 transcripts)

→ we sent “The fair runs Fri–Sun, Oct 9–11.”

→ it said “The fair runs Friday to Sun, October ninth to eleventh.”

• fatal · large numbers — never said “three trillion” (48 of 49 transcripts)

→ we sent “National debt passed 3,000,000,000,000 dollars.”

→ it said “National debt passed three billion dollars.”

+ 7 more fined

Cost / 1M chars

$13.0

Token-billed: $4/1M text in, $21.50/1M audio out; the vendor states ~$0.70 per hour of generated speech (soniox.com/pricing). At 900 chars/min (54,000 chars/hour) that is ~$13 per 1M chars.

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