In case you don't have warranty, I would refrain from changing it yourself.
Voyager tablets require soldering skills to unlink the speaker from the board and to add a new one.
Any phone/tablet repair shop can do it for cheap.
You can easily buy the speaker online and provide it to the repair shop, but most speakers they probably have should do just fine. it doesn't have to be the exact part to work, it just has to fit right.