Cartesia vs OpenAI TTS

Discover key differences between Cartesia and ElevenLabs voice AI models.

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Compare Cartesia and OpenAI TTS Voice Models

Explore the differences between Cartesia and OpenAI TTS voice models. Discover features, pricing, and performance metrics.

Updated on:

Feb 14, 2025

Features

Latency

Latency

Latency

Voice Quality

Voice Quality

Voice Quality

Character Limits

Character Limits

Character Limits

Instant Cloning

Instant Cloning

Instant Cloning

Professional Voice Cloning

Professional Voice Cloning

Professional Voice Cloning

Pronunciation Accuracy

Pronunciation Accuracy

Pronunciation Accuracy

Voice Customizations

Voice Customizations

Voice Customizations

Telephony Optimization

Telephony Optimization

Telephony Optimization

Flexible deployments

Flexible deployments

Flexible deployments

Languages Supported

Languages Supported

Languages Supported

Concurrency

Concurrency

Concurrency

Cartesia

40ms for the Sonic Turbo model, 90ms for the Sonic 2 model

Consistently rated as more natural, expressive, and realistic in blinded human evaluations

Infinite request length

Requires 3 seconds of audio

Requires 30 minutes of audio

IPA support with strong contextual understanding

Slider control for speed and emotion + synthetic voice mixing and design

8kHz audio, telephony optimized voices

Supports both on-prem and on-device deployments

15 languages with extensive dialect coverage

Up to 15 on highest self-serve tier (60 parallel conversations), custom for enterprise

OpenAI Speech to Text

200 ms + network time, slower response times

Lower quality ratings in human evaluations, and limited emotional control

Limited character count for longer texts

Requires 13 seconds of audio

Requires 60 minutes of audio

Less contextual awareness in pronunciation

Basic controls for speed, emotion and similarity

Standard audio quality without optimization

No on-device generation available

57

3-200 per mins

Cartesia - Advanced AI Voice Capabilities

Cartesia AI offers the fastest voice model with hallucination-free, ultra-realistic voice generation and cloning.

No Hallucinations

Cartesia's AI text to speech eliminates errors, ensuring authentic and clear audio output every time.

Enterprise Ready

Enterprise-grade reliability with 99.9% uptime, SOC2 compliance, and full on-premises support.

Latency

We measure latency using the Time to First Audio (TTFA) metric and calculate the 90th percentile score from 100 TTFA measurements for each provider. With a TTFA of 199 ms, Cartesia's Sonic model is significantly faster than ElevenLabs' 832 ms at the self-serve tier (with ElevenLabs reserving slightly lower latency for enterprise customers). Cartesia’s Sonic model is built on a radically more efficient architecture, known as State Space Models (SSMs), which allows for far greater latency optimization than the traditional transformer architecture used by ElevenLabs and other providers. For a side by side comparison, watch the latency demonstration in this video on X.

Pronunciation Accuracy

Using the Time to First Audio (TTFA) metric, Cartesia's Sonic model achieves a TTFA of 199 ms, significantly faster than ElevenLabs' 832 ms. This efficiency is due to Cartesia's advanced State Space Models (SSMs), optimizing latency beyond traditional architectures.

Voice Cloning

Cartesia provides unlimited instant voice cloning. In contrast, ElevenLabs restricts cloning capabilities with tiered plans allowing for 10, 30, 160, or 660 custom voices. Additionally, Cartesia utilizes advanced embedding technology to deliver consistent, high-quality voice clones. Cartesia preserves accents and voice quality even if the original audio clip is noisy. Cartesia's voice mixing and design capabilities also open up a more comprehensive set of diverse voices. In the following samples of Engelbart's clones, it's apparent that Cartesia produces a significantly less noisy and higher quality clone than ElevenLabs.

Voice Design Controllability

Cartesia stands out as the only provider offering emotion and speed modulation features, enabling refined voice adjustments while preserving a natural and seamless auditory experience. Cartesia also allows you to localize the voice to match different accents — you can start with an American voice and have it speak in a French accent, for instance. In comparison, ElevenLabs only offers controls for stability, similarity, and style exaggeration, all of which do not offer clear control for the voice. In the following example where the speaker is addressing a customer complaint, we compare the dial effects from ElevenLabs and Cartesia to find that the ElevenLabs voice sounds similar with the various dials applied while Cartesia's emotion and speed dials convey very noticeable changes.

Pricing Plans for Cartesia and OpenAI TTS

Cartesia

Free - $0 per month with 10k free credits

Pro - $5 per month with 100k credits

Startup - $49 per month with 1.25M credits

Scale - $299 per month with 8M credits

Enterprise - trusted by Fortune 500 companies

OpenAI Speech to Text

TTS - $15 per 1M characters

TTS HD - $30 per 1M characters

Trusted by 50K+ Customers

Trusted by 50K+ Customers

Trusted by 50K+ Customers

Frequently asked questions

How does voice cloning work?

How does voice cloning work?

How does voice cloning work?

What is the latency for voice generation?

What is the latency for voice generation?

What is the latency for voice generation?

Can I customize the cloned voice?

Can I customize the cloned voice?

Can I customize the cloned voice?

How many languages does Cartesia support?

How many languages does Cartesia support?

How many languages does Cartesia support?

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Real-time, multimodal intelligence for every device.

Sign up for early access to new releases

HIPAA

SOC-2 Type II

Real-time, multimodal intelligence for every device.

Sign up for early access to new releases

HIPAA

SOC-2 Type II