Google’s John Mueller recently told in Google Search Central Hangout ” There is no SEO Advantage or benefits to adding an audio version of a text-based web page.
The Question asked by the user during the call “Would adding an audio version of a page’s content help with search in any way?
Is it helping those publishers in search rankings?
John Muller says “Unlike photo and video, Google doesn’t do anything special with audio content. ” Audio content is not processed separately by Google. At most it might be seen as a piece of video content which could result in a video snippet.
Here is what he says
As far as I know we don’t do anything with audio versions of content. We also wouldn’t see that as duplicate content, so it’s not that you have to avoid that.
I mean, duplicate content itself isn’t something you really have to avoid, but even if you wanted to avoid the situation that you’re suddenly ranking for the same things with different pieces of content, the audio version is something that we, as far as I know, would not even process separately.
At most we might see that as a piece of video content and show that also with a video snippet. But, essentially, it wouldn’t help or detract from a page’s overall ranking.”