Content creators armed with marketing AI, enhancing their production capabilities are increasingly turning to AI Text-to-Speech tools. These cutting-edge solutions are revolutionising how we consume information, transforming written text into synthetic voice outputs in multiple languages. This detailed exploration will examine five industry-leading frontrunners of AI technology that excel in producing high-quality audio: ElevenLabs, Google Text-to-Speech AI, OpenAI Text-To-Speech, Genny by Lovo, and Amazon Polly. Their ability to craft synthetic voices with clarity across various languages is innovative and reshaping the future of marketing and content creation.

What is Text-to-Speech AI?

Text-to-speech AI, often abbreviated as TTS, is an assistive technology that uses artificial intelligence systems to convert written text into spoken words. This technology employs deep learning algorithms to synthesise speech closely resembling human voices, providing a clear and understandable audio rendition of the text. TTS is also referred to as "read-aloud" technology and is used not only for creating voice content or enabling communication for those unable to speak, but also for aiding in reading, writing, editing, and even assisting people with focusing.

The popularity of TTS is growing due to its practical uses and ability to personalise experiences. Features like 'clone your own voice' are becoming increasingly sought after. The evolution of TTS technology, often called neural text-to-speech, has led to more natural and varied auditory experiences. This is due to advancements in AI and deep learning, which have created more human-like speech outputs. As such, TTS has become an essential asset in the realm of AI voice tools and text-to-speech generators.

How TTS Works

The technology underpinning TTS is intricate but can be simplified. At its core, TTS involves a multi-step process that includes linguistic analysis and speech synthesis. When a text input is provided, the AI system breaks down the text into its linguistic components, such as words, punctuation, and sentence structure. It then determines the human aspects of each word, including its pronunciation, stress, and intonation patterns.

Like the ones we’re exploring today, commercial models of TTS typically operate via APIs. This allows developers to seamlessly integrate these synthetic voices into their applications. The business model for these AI text-to-speech services is generally based on usage, where companies are charged monthly depending on the number of words, tokens, or the time required for generating speech. This scalable approach makes it accessible for various users, from individuals needing a text-to-speech generator for personal projects to businesses requiring hours of voice for professional services.

However, it's important to note that not all TTS applications allow for redistributing generated audio files. If users plan to redistribute their audio files, they must ensure the TTS application is built for commercial, business, or public use. Several AI voice generators offer commercial rights for businesses, including Lovo.ai, Resemble.ai, Play.ht, Murf.ai, Amazon Polly, Microsoft Azure Text to Speech, TikTok Text-to-Speech, and Google Text-to-Speech.

Listen to a comparison of the five AI Text-to-Speech tools listed in the article below: 

ElevenLabs

ElevenLabs is an AI Text-to-Speech (TTS) tool known for its natural-sounding voices and smooth integration features. It uses sophisticated machine-learning algorithms to craft speech patterns that rival natural human articulation, making it an indispensable asset for various uses. The quality of ElevenLabs' voice synthesis,  the extensive library of voices and the ease of use make it a leader in the field.

Features and Benefits of ElevenLabs

ElevenLabs offers an impressive array of languages and dialects, broadening its appeal globally. The platform's collection of voices captures the subtleties of human expression, providing an engaging and comfortably familiar auditory experience. Users can easily tailor speech outputs to their precise requirements through a user-friendly interface.

Dubbing

ElevenLabs has introduced a new dubbing feature that allows users to reproduce audio from one language in 28 others while maintaining the speaker's voice and speech patterns. However, my own tests with this feature have not delivered great results, indicating that there is room for improvement.

Voice Cloning

ElevenLabs offers voice cloning capabilities, allowing users to create a near-perfect clone of a voice from just a few minutes of audio 2. However, the voice cloning feature may not always produce a perfect match. In my own testing, I would say Elevenlabs provides an 80% match of the cloned voices. Professional Voice Cloning, which requires more training data, is available for enterprise-level clients and can produce more accurate results.

Use Cases

The utility of ElevenLabs stretches across various industries, from publishing to e-learning, enhancing the educational journey with an immersive auditory layer. Customers frequently highlight the platform's superior audio quality, intuitive nature, and responsive customer support. However, it's essential to consider the limitations of the technology, especially when cloning unique voices or accents, as the AI might not have heard similar voices during training.

HeyGen, the increasingly popular AI avatar start-up, which enables users to create incredible AI videos with them dubbed into different languages, or add voiceovers to characters, provides API integration with ElevenLabs. Pictory, another popular AI video production tool, also uses ElevenLabs to power its voice-overs.

Google Text-to-Speech AI

Customer-Centric Overview of Google Text-to-Speech AI

Google Text-to-Speech AI is a customer favourite, renowned for converting text to 'beautiful sound voices' and its seamless integration with other Google Cloud services. It's celebrated for its simplicity and efficiency, a product that stands as a testament to Google's commitment to user-friendly innovation. It's also very cheap compared to some of the competition.

Features and Benefits

Valued for its wide-ranging functionalities, Google's TTS tool offers multilingual capabilities and a library of natural-sounding voices that resonate with users. Its flexibility in speech parameters is often celebrated in customer testimonials, integral to the content creation, particularly for 'indiscernibly human' voiceovers.

Pricing Model

The tool's pricing model is user-conscious, with substantial free usage and scalable pricing. User feedback underlines the value of the free credits offered, enabling a smooth transition into AI-powered audio without immediate cost concerns. New users get $300 of free credits and up to 4 million characters of TTS free per month.

Customer reviews form the core of our endorsement for Google Text-to-Speech AI. Users on Capterra express appreciation for how the tool 'makes life and work very easy,' highlighting its comprehensive service and convenience. Its widespread adoption, especially for voiceovers that are 'just convenient and sound indiscernibly human,' speaks volumes of its standing as a top-tier choice.

OpenAI Text-to-Speech

The OpenAI Text-to-Speech API is a sophisticated endpoint that turns text into lifelike spoken audio. Announced at the November 2023 OpenAI Dev Day with six built-in voices, this API facilitates a range of applications, from narrating blog posts to producing multilingual spoken content, and it can even provide real-time audio output through streaming.

Capabilities and Usage of OpenAI's TTS

The API is designed with standard and high-definition models and caters to different quality requirements and use cases. The tts-1 model is ideal for real-time applications, offering lower latency at a more affordable rate. For those seeking higher-quality audio, the tts-1-hd model provides an elevated audio experience with less static and more precise diction.

Voices and Language Support

The model is limited to six voices at the time of writing - Alloy, Echo, Fable, Onyx, Nova, and Shimmer - all optimised for English language speech. One of the six voices (Fable) is British(ish). The TTS model also aligns with the Whisper model for language support, accommodating a broad range of languages and delivering commendable performance even for languages beyond its optimised English voices.

Streaming and Real-Time Audio

The API supports real-time audio streaming for applications requiring immediate audio feedback. This ensures that audio can be played back even before the entire file is rendered, catering to interactive and responsive use cases.

Pricing and other considerations

The API's pricing is competitive, starting at $0.015 per 1,000 input characters for the standard model, making it an economical choice for developers. While the API doesn’t currently allow for emotional range control or custom voice creation, it stands out for its straightforward integration and ease of use.

The OpenAI TTS offers good-quality audio, but the range of voices is limited. The HD variant does provide some nuance in emotional expression, although it may not reach the level of sophistication offered by ElevenLabs. However, its competitive pricing makes it a viable option for those prioritising cost-effectiveness. For detailed pricing information, it’s best to refer to OpenAI's pricing page.

How to access OpenAI Text-to-Speech online?

If you don't know how to use APIs, accessing OpenAI Text-to-Speech can be difficult. However, some friendly people have made using the tool very easy with a publicly accessible tool that allows you to bring your own OpenAI API key and start creating in seconds.

To get started using OpenAI's test-to-speech generator, visit Marco Frodl's OpenAI Text-To-Speech Generator (TTS-1 Model) project on HuggingFace and enter your OpenAI API Key. Then, you simply choose your voice, and away you go! It's that simple. If you don't have an OpenAI API Key, read this article.

Genny by LOVO AI

Genny by LOVO AI is not just an AI voice generator; it's an immersive experience that captivates audiences with hyper-realistic AI voices. At least, that's what the marketing says. Used by over a million users and award-winning in its class, LOVO's AI Voice Generator and text-to-speech software boast an impressive repertoire of over 500 voices across 100 languages.

Diverse Voices That Speak to the World

LOVO's strength lies in its diversity, offering voices like Chloe Woods and Sophia Butler for English female narration, and Thomas Coleman and Bryan Lee Jr. for English male voices, not to mention the festive charm of Santa Claus. These voices are varied and designed to deliver specific content needs such as audiobooks, educational material, and much more.

Full-Spectrum AI Voice Generator

Genny's feature-rich platform is at the core of LOVO's offering, providing everything needed for voiceover production. Genny is a comprehensive tool for content creators, from scripts and images to voiceovers and translations. Thanks to its advanced text-to-speech engine that understands context and injects emotion into voiceovers, it promises substantial savings in both money and time.

Script Editing with Video

LOVO's Genny editing suite provides a very different user experience than the other tools on this list. Users can edit videos and add multiple voices to a creation, so you can easily add multiple characters to a composition. Inserting video clips or images is as easy as dropping them into the editing timeline, which provides a more professional editing experience.

Tailored Content Creation with LOVO

Whether for advertisements, education, corporate training, or social media, LOVO's tailored AI voices enrich any content type. With the new versatile API, developers can integrate LOVO's advanced voices into their applications, enhancing user experiences with just a few lines of code.

Amazon Polly

Amazon Polly, available through AWS, stands at the forefront of text-to-speech solutions, offering high-quality, natural-sounding voices in 38 languages. This service is not just about breadth but depth, with the ability to bring a human touch to various applications.

The Power of Deep Learning

Utilising advanced deep learning technologies, Amazon Polly transcends the typical robotic speech, allowing content creators to convert articles and texts into engaging speech. It's built to cater to a global audience, enabling the creation of speech-activated applications that resonate with users worldwide.

An Abundance of Free Characters

With the AWS Free Tier, developers are welcomed with open arms, receiving 5 million characters free per month for the first 12 months. This generous offering makes Polly an excellent starting point for developers exploring the realm of speech synthesis.

Versatile Control and Customisation

Amazon Polly goes beyond mere voice generation; it provides tools for customisation and control, including support for lexicons and Speech Synthesis Markup Language (SSML) tags. These features allow for nuanced adjustments in speaking style, rate, pitch, and volume, ensuring the output is tailored to the specific needs of any project.

Consistent Performance and Accessibility

The service prides itself on delivering consistently fast response times, ensuring that applications provide conversational experiences without delay. With the ability to store and redistribute speech in standard audio formats like MP3 and OGG, Polly integrates smoothly into various platforms.

Engaging and Interactive Use Cases

Whether it’s adding dynamic speech to RSS feeds, websites, or interactive voice response systems, Amazon Polly engages users with a natural voice, enhancing the user experience. Polly's lifelike voices and the ability to replay speech output make it an indispensable tool for developers looking to craft interactive and automated systems.

Hands-On Experience for Developers

For those with technical expertise, Polly invites experimentation and hands-on play. With an AWS account, you can access the Amazon Polly console and explore its capabilities firsthand. The voices offered by Polly are known for their clarity and low latency, providing a seamless experience that stands up to real-world expectations.

Conclusion

As we've explored, the spectrum of AI text-to-speech tools offers a symphony of voices that can speak to every need and preference.

Each platform crafts a unique auditory narrative from ElevenLabs’ near-human cadences to Google's integration prowess, OpenAI's streaming capabilities, Genny's diversity, and the expansive reach of Amazon Poll. Looking to the horizon, the evolution of these tools promises to further dissolve the barriers between humans and machines, creating a world where information is not only accessible but resonates with the warmth of human touch.

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Martin Broadhurst
Post by Martin Broadhurst
November 22, 2023
Martin Broadhurst is a sales and marketing technology consultant with specialising in HubSpot and Marketing AI technology.

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