That's the sad part of the story.
Basically, the only two reading systems that allow you to
sideload an EPUB3 Audio-eBook (= EPUB 3 reflowable with Media Overlays) and provide a
decent UI/UX are:
1. Linux/OS X/Windows: Readium, free extension for Chrome developed by the IDPF.
https://chrome.google.com/webstore/d...foaglimekefifl
2. Android/iOS: Menestrello, free app that I developed --- no longer developed/maintained.
http://www.readbeyond.it/menestrello/index.html
Other apps (e.g., AZARDI, Kobo, Gitden, ADE 4) can open Audio-eBooks, but they are buggy and/or does not provide a good (= specific for Audio-eBooks) UI/UX. Unfortunately, a majority of the apps out there does not support Media Overlays in reflowable EPUB 3 files (notably, iBooks).
Finally, one can use Readium JS to host on a Web server, for example:
http://www.readbeyond.it/ebooks.html (click on Read+Listen on one book of your choice)