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Comment by dheera | Hacker News Reader

Why is the quality of open source TTS so horribly, horribly, horribly behind the commercial neural ones? This is nowhere near the quality of Google, Microsoft, or Amazon TTS, yet for image generation and LLMs almost everything outside of OpenAI seems to be open-sourced.

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I'm glad that it doesn't. A lot of us use these voices as an accessibility tool in our screen readers. They need to perform well and be understandable at very high rate, and they need to be very responsive. ESpeak is one of the most responsive speech synths out there, so for a screen reader this means key press to speech output is extremely low. Adding AI would just make this a lot slower and unpredictable, and unusable for daily work, at least right now. This is anecdotal, but part of what makes a synth work well at high speech rates is predictability. I know how a speech synth is going to say something exactly. This let's me put more focus on the thing I'm doing rather than trying to decipher what the synth is saying. Neural TTS always has differences in how they say a thing, and at times, those differences can be large enough to trip me up. Then I'm focusing on the speech again and not what I'm doing. But ESpeak is very predictable, so I can let my brain do the pattern matching and focus actively on something else.

The quality also depends on the type of model. I'm not really sure what ESpeak-ng actually uses? The classical TTS approaches often use some statistical model (e.g. HMM) + some vocoder. You can get to intelligible speech pretty easily but the quality is bad (w.r.t. how natural it sounds).

There are better open source TTS models. E.g. check https://github.com/neonbjb/tortoise-tts or https://github.com/NVIDIA/tacotron2. Or here for more: https://www.reddit.com/r/MachineLearning/comments/12kjof5/d_...

almost like there's a few bilion dollars difference in their budgets

Sure but it's been 15 years and the quality of the espeak command is equally horrible. I would have expected some changes ... especially considering even the free TTS inside Google Chrome is actually pretty decent, that could just be extracted and packaged up as a new version of espeak.

Festival it's nicer; Flite would run on a toaster and Mbrola can work with Espeak but the data it's restricted for commercial usage.

Deepspeech from Mozilla is open source. Did you know this one?

From the samples I listened, it sounds great to me?

I have to dry this, thanks! Unfortunately I couldn't find samples on their git repo and it looks like it isn't apt-gettable. Maybe that's part of the reason.

They should make it so that I can do

    sudo apt-get install deepspeech
    sudo ln -s /usr/bin/deepspeech /usr/bin/espeak

Anything more than that is an impediment to mass adoption.

Seems they need some new product management ...

As I understand it DeepSpeech is no longer actively maintained by Mozilla: https://github.com/mozilla/DeepSpeech/issues/3693

For Text To Speech, I've found Piper TTS useful (for situations where "quality"=="realistic"/"natual"): https://github.com/rhasspy/piper

For Speech to Text (which AIUI DeepSpeech provided), I've had some success with Vosk: https://github.com/alphacep/vosk-api

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