ElevenLabsCartesiaAudio matchupSpeech output
Eleven Flash v2.5vs.Sonic 3.6
Which model is better?
Sonic 3.6 does better in independent tests.
Pick Eleven Flash v2.5 for
Pick Sonic 3.6 for
Shared tests
Independent evaluators and leaderboards only, the newest shared snapshot per evaluator. With 95 % ranges a lead counts when they do not overlap; for hit rates, when it holds in a 95 % test. Without any uncertainty figure at most “slightly ahead”.
Cekura
depends on the subtestEleven Flash v2.5 is clearly ahead in 0 of 8 subtests and slightly in 3, Sonic 3.6 in 0 clearly and slightly in 3. 2 are level.
Cekura TTS non-streaming latency
lower is better, as of October 19, 2026
Cekura TTS streaming latency median
lower is better, as of October 19, 2026
Cekura TTS hard-part accuracy: codes and addresses
as of October 19, 2026
Show all 8 subtests
| Subtest | Eleven Flash v2.5 | Sonic 3.6 | Verdict |
|---|---|---|---|
| Cekura TTS non-streaming latency (lower is better) | 182 ms | 286 ms | Eleven Flash v2.5 slightly ahead |
| Cekura TTS streaming latency median (lower is better) | 177 ms | 270 ms | Eleven Flash v2.5 slightly ahead |
| Cekura TTS hard-part accuracy: codes and addresses | 55.0 % | 75.0 % | Sonic 3.6 slightly ahead |
| Cekura TTS hard-part accuracy: read from context | 75.0 % | 58.0 % | Eleven Flash v2.5 slightly ahead |
| Cekura TTS hard-part accuracy: numbers and shorthand | 55.0 % | 71.0 % | Sonic 3.6 slightly ahead |
| Cekura TTS ASR-based hard-part accuracy estimate | 64.4 % | 74.9 % | Sonic 3.6 slightly ahead |
| Cekura UTMOS-predicted naturalness | 4 | 4 | level |
| Cekura TTS hard-part accuracy: medical terms | 100.0 % | 100.0 % | level |
Source · latest October 19, 2026
Artificial Analysis
Sonic 3.6 aheadSonic 3.6 is clearly ahead in 2 of 2 subtests, Eleven Flash v2.5 in none.
Artificial Analysis Provider Voice Arena preference
95 % ranges 1,065 to 1,085 and 1,280 to 1,306, as of November 3, 2026
Artificial Analysis Controlled Voice Arena Elo
95 % ranges 976 to 1,000 and 1,135 to 1,159, as of November 3, 2026
Source · latest November 3, 2026
All data side by side
Prices are verbatim from the provider, because audio models bill per minute, character or token.
| Eleven Flash v2.5 | Sonic 3.6 | |
|---|---|---|
| Task | Speech output | Speech output |
| Developer | ElevenLabs | Cartesia |
| Status | Active | Active |
| Weights | proprietary | proprietary |
| Runs locally | no | no |
| Popularity (out of 100) | 22 | 39 |