Which is faster, Gradium TTS or Cartesia Sonic 3?

Speed: not compared, because a benchmark in this index does not publish it for both models.

Which is rated higher by listeners, Gradium TTS or Cartesia Sonic 3?

Listener rating: Gradium TTS comes out ahead (Elo 1,174 against 1,054; scores within each other's 95% intervals are a tie).

Which is cheaper, Gradium TTS or Cartesia Sonic 3?

Price: Gradium TTS comes out ahead ($36 to $57.8 against $49 to $50 per million characters, lowest list price).

Why is this model always on the left?

Gradium TTS is the reference model of this site's comparison pages: it is set against every other listed model. The editor chose it; it is not chosen by rank.

Comparison · read on October 27, 2026

Gradium TTS vs Cartesia Sonic 3

Two text-to-speech (TTS) models side by side, from four public benchmarks. Speed comes first, then listener rating and price; the three are never added into a score.

Measure	Gradium TTS	Cartesia Sonic 3
Provider	Gradium	Cartesia
Speed tier	Headroom	Not timed
P95 time to first audio	104.3 ms	Not timed
Median time to first audio	53.7 ms	Not timed
Listener Elo	1,174	1,054
Price per 1M characters	$36 to $57.8	$49 to $50
Access	Proprietary	Proprietary
Rank in the full ranking	2	62
Rank by use case	Customer service 1, Voice agents 2, Assistants 1, Entertainment 1, Knowledge sharing 1	Customer service 34, Assistants 49, Entertainment 49, Knowledge sharing 49

Which should you choose?

Speed: not compared, because a benchmark in this index does not publish it for both models.
Listener rating: Gradium TTS comes out ahead (Elo 1,174 against 1,054; scores within each other's 95% intervals are a tie).
Price: Gradium TTS comes out ahead ($36 to $57.8 against $49 to $50 per million characters, lowest list price).

Where a model is not timed or not rated, nothing is estimated. See each model page for its sources: Gradium TTS and Cartesia Sonic 3.

Frequently asked questions

Which is faster, Gradium TTS or Cartesia Sonic 3?: Speed: not compared, because a benchmark in this index does not publish it for both models.
Which is rated higher by listeners, Gradium TTS or Cartesia Sonic 3?: Listener rating: Gradium TTS comes out ahead (Elo 1,174 against 1,054; scores within each other's 95% intervals are a tie).
Which is cheaper, Gradium TTS or Cartesia Sonic 3?: Price: Gradium TTS comes out ahead ($36 to $57.8 against $49 to $50 per million characters, lowest list price).
Why is this model always on the left?: Gradium TTS is the reference model of this site's comparison pages: it is set against every other listed model. The editor chose it; it is not chosen by rank.