I suspect they might be using voice lines from Chinese gacha games in addition to what clearly sound like VTubers, YouTubers, and Chinese TV documentary narrations. Those games all come with clean monaural CN/JP/EN files consistent in contents across language for all regions, for, an obvious[1] reason.

1: https://old.reddit.com/r/ZenlessZoneZero/comments/1gqmtl1/th...

> do most of the english audio samples sound like anime voices?

100% I was thinking the same thing.

Well, if you look at the prompts, they are basically told to sound like that.

And if you ask me, I think these models were trained on tween fiction podcasts. (My kids listen to a lot of these and dramatic over-acting seems to be the industry standard.)

Also, their middle-aged adult with an "American English" accent sounds like any American I've ever met. More like a bad Sean Connery impersonator.

The real value I see is being able to clone a voice and change timbre and characteristics of the voice to be able to quickly generate voice overs, narrations, voice acting, etc. It's superb!

Also like some popular youtubers and popular speakers.

even the Japanese audio samples sound like anime

subbed audio training data (much better than cc data) is better