Cartesia
sonic-3.5
Measured 2026-07-03
Naturalness
1574
Win % · 95% CI
65%
58–71%
Drift
13
Synth p50
121ms
121–236 p50–p90
Robustness
0.55
Fined:
• fatal · currency — dropped the minus sign (7 of 7 transcripts)
→ we sent “The balance is -$12.50.”
→ it said “The balance is $12.50.”
• fatal · currency — dropped the minus sign (7 of 7 transcripts)
→ we sent “Your balance is -$1,204.50 as of today.”
→ it said “Your balance is $1,204.50 as of today.”
• fatal · currency — dropped the minus sign (7 of 7 transcripts)
→ we sent “A refund of -$0.99 was applied.”
→ it said “A refund of 99 cents was applied.”
• fatal · currency (international, ×0.4) — dropped the minus sign (7 of 7 transcripts)
→ we sent “Balance: -€45,90 outstanding.”
→ it said “Balance: €45,90 outstanding.”
• minor · dates — kept the value but never said “october”; a prompt fixes this (6 of 23 transcripts)
→ we sent “The deadline moved to 10/02.”
→ it said “The deadline moved to ten zero two.”
• minor · dates — kept the value but never said “march”; a prompt fixes this (4 of 7 transcripts)
→ we sent “Your slot is 03/09 this year.”
→ it said “Your slot is zero three zero nine this year.”
• minor · units — kept the value but never said “two hundred fifty” or “gigabyte”; a prompt fixes this (6 of 7 transcripts)
→ we sent “You have 250GB remaining.”
→ it said “You have two five zero GB remaining.”
• minor · units — said “slash” out loud; a prompt fixes this (4 of 7 transcripts)
→ we sent “Wind is 25km/h northwest.”
→ it said “Wind is 25 kilometers slash h northwest.”
Cost / 1M chars
$50.0
1 credit/char on Pro, the cheapest paid plan; $39.2 at Startup, $37.4 at Scale. Cloned voices bill 1.5x.
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