audio model comparison
AssemblyAI-TTS-1 vs Sonic 3.6
AssemblyAI-TTS-1 and Sonic 3.6 are both current audio models, from AssemblyAI and Cartesia. AssemblyAI-TTS-1 lists $0.000015 and Sonic 3.6 $0.000065 (Pro plan overage) per character, at different tiers, so the prices are not like for like. On Artificial Analysis Speech Arena, AssemblyAI-TTS-1 scores 1221 Elo and Sonic 3.6 1293 Elo (Artificial Analysis, measured November 3, 2026).
- Higher Artificial Analysis Speech Arena
- Sonic 3.61293 Elo against 1221 Elo
- Newer release
- AssemblyAI-TTS-1Oct 2026 against Aug 2026
Data verified November 3, 2026 · Dataset 2026-11-03
Side by side
AssemblyAI-TTS-1 and Sonic 3.6, line by line
Prices in effect today, compared at the same tier wherever both list one. The better value in each row is highlighted.
| Fact | AssemblyAI-TTS-1 | Sonic 3.6 |
|---|---|---|
| Price | ||
| Price per character | $0.000015 | $0.000065 (Pro plan overage) |
| Independent benchmarks | ||
| Artificial Analysis Speech Arena | 1221 Elo (#6 of 13) | 1293 Elo (#3 of 13) (better) |
| Specs | ||
| Provider | AssemblyAI | Cartesia |
| Release date | October 28, 2026 | August 27, 2026 |
| Access | API only | API only |
| Context window | Not reported | Not reported |
| Max output | Not reported | Not reported |
| Input | text | text |
| Output | audio | audio |
The two list prices for different tiers, shown in brackets, so neither is marked cheaper.
Charts
Against every current audio model
Where AssemblyAI-TTS-1 and Sonic 3.6 land among the current models of their task, on every independent benchmark, on price and on context.
Where each stands
On Artificial Analysis Speech Arena, AssemblyAI-TTS-1 ranks #6 and Sonic 3.6 #3 of 13 current models. Each bar is the share of current models it beats: on score, price and context.
Independent benchmarks
Artificial Analysis Speech Arena
AssemblyAI-TTS-1:#6of 13
1,221 Elo · ahead of 58%
Sonic 3.6:#3of 13
1,293 Elo · ahead of 83%
Price and context
Price per character
AssemblyAI-TTS-1:#2of 11
$0.000015 · cheaper than 70%
Sonic 3.6:#8of 11
$0.000065 · cheaper than 30%
Cost
What each costs
Example workloads at each provider's listed rates, then every other rate either one lists. The cheaper figure in each row is highlighted.
| Workload or rate | AssemblyAI-TTS-1 | Sonic 3.6 |
|---|---|---|
| Example workloads | ||
| 1M characters | $15 | $65 (Pro plan overage) |
Your own bill will differ. These figures use list prices and example workloads. The AI Model Cost Audit reviews your real usage, shortlists models that score as well for each task for less, and estimates the savings.
Launch price $100, regular price $150
Verdict
When to choose each
AssemblyAI-TTS-1
Where it leads
No measured lead over Sonic 3.6 in this data.
Best for
- Voice agents on live phone calls
- High-volume speech where the cost per character matters
Watch out for
- Six languages at launch; AssemblyAI says more languages and accents will follow
- No fine-tuned (Pro) voice cloning, pronunciation dictionaries or emotion tags at launch
- The head-to-head figures in the launch post are AssemblyAI tests
Sonic 3.6
Where it leads
- Higher Artificial Analysis Speech Arena score, 1293 Elo vs 1221 Elo
Best for
- Multilingual speech for voice agents
- Indian-language and Hinglish speech
Watch out for
- Credit-based plans only (1 credit per character); the recorded rate is the Pro plan overage of $65 per 1M characters, falling to $38 on the Scale plan
- Cartesia does not state latency figures for this version
From benchmark to production
Building on AssemblyAI-TTS-1 or Sonic 3.6?
Public scores rarely hold on your own data. We test both models on your real tasks, then build the agent or pipeline around the one that wins.
AI Model Cost AuditLaunch price $100, regular price $150What the audit includes
FAQ
AssemblyAI-TTS-1 vs Sonic 3.6 FAQ
Which is cheaper, AssemblyAI-TTS-1 or Sonic 3.6?
AssemblyAI-TTS-1 lists $0.000015 and Sonic 3.6 $0.000065 (Pro plan overage) per character, at different tiers, so the prices are not like for like.
Which scores higher on independent benchmarks, AssemblyAI-TTS-1 or Sonic 3.6?
Sonic 3.6 leads on Artificial Analysis Speech Arena, 1293 Elo to 1221 Elo. Scores are independent evaluations, not either vendor's launch figures.
Further reading
More on AssemblyAI-TTS-1 and Sonic 3.6
Related comparisons
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- Eleven v4 Turbo vs Sonic 3.6
- AssemblyAI-TTS-1 vs TTS-1
- Eleven v4 vs Sonic 3.6
- AssemblyAI-TTS-1 vs Voxtral Mini TTS 3
- Gemini 3.8 Flash TTS vs Sonic 3.6
- AssemblyAI-TTS-1 vs MAI-Voice-2.1
- Eleven Flash v2.5 vs Sonic 3.6
- AssemblyAI-TTS-1 vs MAI-Voice-2.1-Flash
- Eleven Multilingual v2 vs Sonic 3.6
Production evaluation
Choosing between AssemblyAI-TTS-1 and Sonic 3.6?
Public benchmarks narrow the shortlist. We run both on your own tasks, data and cost limits, then build the routing and review controls to run the winner in production.
- A head-to-head evaluation on your real workload
- Routing between models by cost and difficulty