[Free] Create Audiobooks with Speech Synthesis! DIY Guide Using TTS Services

I want to make my own audiobooks using speech synthesis!

An audiobook reads the content of a book aloud.

While audiobooks are distributed for a fee, you can actually create them yourself easily and for free using speech synthesis.

To make an audiobook yourself, we recommend using a free AI reading service.

For those who want to make their own audiobooks, this article explains the process of speech synthesis using a free AI reading service.

Recommended reading services for those who want to synthesize speech for audiobooks

There is a recommended service for those who want to synthesize speech and create audiobooks themselves.

It is the latest AI reading service, "Ondoku".

"Ondoku" is a web service that allows anyone to read text aloud easily.

Simply open the page from here, paste your text, and you can read the text aloud immediately for free.

Since it is a web service used from a browser, no installation is required.

You can synthesize speech for audiobooks with the clear and easy-to-hear voice unique to the latest AI.

If you want to make an audiobook, why not start by using Ondoku here?

Original audiobooks made with speech synthesis

An audiobook is a book that you "read by listening."

Actually, anyone can easily make an audiobook by using AI speech synthesis.

Features of audiobooks

An audiobook is a book read by listening, where the content of the book is read aloud and made playable as an audio file.

They have been sold in formats such as cassette tapes and CDs for a long time, but they have become much more familiar, especially since the appearance of smartphones.

Although many audiobooks are sold as audio files that can be played on smartphones, there are still fewer varieties compared to paper books and e-books.

In such cases, self-making (self-digitizing) an audiobook is recommended.

Actually, anyone can easily make an audiobook if they use AI speech synthesis.

Scenes where audiobooks are useful

Aren't paper books or e-books good enough?

Actually, audiobooks have several scenes where they excel, unique to books that you "read with your ears."

1. During exercise

Being able to listen to books while exercising, such as running, walking, or training at the gym, is a major benefit of audiobooks.

By synthesizing speech for an original audiobook, you can turn exercise time into study time.

In fact, the activity of listening to audio while exercising is gaining attention as "mimi-katsu" (ear-based activity).

This is a way to use audiobooks that you should definitely incorporate into your life.

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2. While driving

Listening to books while driving a car is also a unique use for audiobooks.

People who commute by train can read during their commute, but you usually cannot read a book if you commute by car.

With an audiobook, it is possible to listen to and read your favorite books during your commute.

3. Reading for the visually impaired

Braille books and audiobooks have been made for a long time for the visually impaired.

Until now, professional narrators or voice actors had to read them, so the varieties of audiobooks were limited.

By using AI speech synthesis, it is possible to dramatically increase the options for audiobooks for the visually impaired.

5 Recommended Speech Synthesis Services and Software for Audiobooks

If I'm going to make an audiobook, what method should I use for speech synthesis?

Here are some recommended speech synthesis services and software for making audiobooks!

• Ondoku
• CeVIO
• VOICEVOX
• AquesTalkPlayer
• A.I.VOICE

1. Ondoku

"Ondoku" is an AI speech synthesis service recommended for creating audiobooks.

Since it is a web service used from a browser, no installation is required and it can be used immediately.

Moreover, "Ondoku" allows for free speech synthesis!

You can experience the realistic and easy-to-hear reading voice unique to the latest AI for free right now.

Simple and easy-to-use reading screen

Using "Ondoku" is very easy.

Once you open the top page, just paste the text into the text box and press the "Read aloud" button.

Speech synthesis is completed quickly, and you can download the MP3 file.

16 types of Japanese voices

In "Ondoku", Japanese reading is possible with 16 types of voices.

Free trial listening of 16 types of voices for text-to-speech software Ondoku. Change impressions with pitch variation

Ondoku has 16 types of Japanese voices. Of course, both male and female voices are available. We have made it possible to trial listen to the 8 most commonly used Japanese voices and how they sound when their pitch is adjusted.

There are many natural voices that aren't overly character-driven, so you can focus on the content of the book without distraction.

You can synthesize speech with the perfect voice to match the author or the content of the book.

Foreign language speech synthesis is also possible

"Ondoku" supports speech synthesis in over 48 languages, including Japanese and English!

You can also use it for listening practice by reading foreign language books aloud.

[Ondoku] Audition the types of voices and sample audio for supported languages

Here, we will introduce the supported languages and sample voices of Ondoku.

Speech synthesis service available for free

And "Ondoku" can be used for free!

You can synthesize 1,000 characters without logging in, and 5,000 characters for free when you log in, so you can easily check what kind of voice can be read aloud right now.

If you are looking for a method of speech synthesis for audiobooks, why not experience "Ondoku" for free first?

2. CeVIO

CeVIO is AI speech synthesis software compatible with Windows.

It uses unique AI developed by a venture company from the Nagoya Institute of Technology, and among paid software, it allows for particularly natural and easy-to-hear speech synthesis.

Package and download versions are available.

Since it excels at expressive reading, it is recommended for those who want to synthesize speech for novels and turn them into audiobooks.

3. VOICEVOX

VOICEVOX is speech synthesis software compatible with Windows, Mac, and Linux.

It is used by downloading from the official website.

It is famous as software that can read aloud in the voices of characters such as Zundamon, Kasukabe Tsumugi, and Shikoku Metan, but it can also be used for speech synthesis of audiobooks.

As neutral voices suitable for audiobooks,

• Shikoku Metan
• Meimei Himari

are recommended.

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4. AquesTalkPlayer

AquesTalkPlayer is speech synthesis software for Windows provided by Aquest Co., Ltd., which is also known as the developer of the so-called "Yukkuri Voice."

Many voices other than Yukkuri Voice are available, allowing for reading with voices that are not too character-heavy and easy to use for audiobooks.

It is not as realistic compared to the latest AI speech synthesis, but the point is that its operation is lightweight instead.

This speech synthesis software is recommended if you don't prioritize realism much and just want the content of the book to be read aloud.

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5. A.I.VOICE

A.I.VOICE is paid speech synthesis software that allows for reading with realistic and easy-to-hear character voices.

It is compatible with Windows and Mac, and package and download versions are available.

The lineup includes characters that were also developed in the "VOICEROID" series, such as Yuzuki Yukari, Kizuna Akari, and Kotonoha Akane/Aoi.

It is also possible to read with voices that are easy to use for audiobook reading and do not show too much character.

How to synthesize speech for audiobooks with a reading service

How do you make an audiobook?

We will explain the process of creating an audiobook for free using the reading service Ondoku!

1. Prepare the original text

First, prepare the text that will serve as the basis for the audiobook.

As an example, we will use text from the website "Aozora Bunko," which publishes copyright-free writing.

(Click here for an explanation on how to remove rubies from Aozora Bunko text.)

2. Open the "Ondoku" page

Open the Ondoku top page from here.

3. Paste the text

Paste the text into the text box.

4. Set the voice type and speed

Adjust the voice type and reading speed.

5. Press the "Read aloud" button to start speech synthesis

When preparation is complete, press the "Read aloud" button.

"Loading" will be displayed, and speech synthesis will begin.

6. Speech synthesis completed

Speech synthesis on Ondoku is completed quickly.

Once the speech synthesis is finished, the screen will automatically switch, and the audio will be played in the browser.

Example: Reading 1,000 characters takes only a few seconds.

7. Download the file

When speech synthesis is completed, the "Download" button is displayed.

When you press the "Download" button, the synthesized file will be downloaded in MP3 format.

This completes the process of synthesizing speech for your own audiobook using Ondoku.

Tips for making audiobooks with speech synthesis

Here is some useful information when self-digitizing audiobooks with speech synthesis.

Be careful with copyrights

When making audiobooks with speech synthesis, caution regarding copyright is necessary.

There is no problem if you listen to the read-aloud audio personally, but you cannot sell it or distribute it for free.

Be especially careful when using text that is not out of copyright, such as books digitized via OCR.

If the source is copyright-free text like "Aozora Bunko," you can create audiobooks without copyright issues.

How to remove rubies from Aozora Bunko text?

Aozora Bunko text has rubies (reading aids), as seen in this image (Natsume Soseki's "Botchan").

Because rubies cause the reading aids to be read aloud along with the main text, we recommend using a tool to remove rubies in advance when making an audiobook from Aozora Bunko.

Tools for removing rubies

• Aozora Bunko Ruby Removal Tool: Long Text Version
• RubyMate

Example of removing rubies

When using the "Aozora Bunko Ruby Removal Tool: Long Text Version," paste the URL and press "Submit."

Then, the reading aid portions are removed like this, resulting in the correct text.

Guidelines for the number of characters for making an audiobook

The number of characters you can synthesize for free on Ondoku is:

• Without logging in: 1,000 characters
• With logging in: 5,000 characters

For paperbacks or new books, the number of characters per page is around 600.

On Ondoku, you can synthesize and read aloud about 8 to 9 pages worth of content for free.

Since the number of characters per book is often about 80,000 to 120,000 for paperbacks or new books, we recommend subscribing to a paid plan if you want to synthesize an entire book to make an audiobook.

The paid plans for Ondoku are as follows:

With the Value Plan, you can make 4 original audiobooks every month, and with the Premium Plan, you can make as many as 10 every month!

Since it can read aloud much more affordably than purchasing paid software, we recommend Ondoku if you are unsure about the speech synthesis method for audiobooks.