Since 2016 WhatsApp has changed the audio format for its voice notes to the opus format, which is not supported by the most Android operating systems.
With Opus Player you can listen this audio file in your file manager. Opus Player is compatible with most file managers on Google Play.
-CHOOSE THE AUDIO OUTPUT: you can switch your audio output from the standard multimedia to the call audio output. It is very useful if you are in a silence environment (like libraries or classrooms) and it is easy like pressing a button.
-USE IT WITH WHATSAPP: if you don’t trust in the Whatsapp’s sensor system for switching the audio output, you can use Opus Player, exploiting the simple user interface provided by it. Just long press on the voice notes, press on the share button and select Opus Player.
-WHATSAPP VOICE NOTES HISTORY: Opus Player takes a history of all your voice notes, received and sent through WhatsApp, and it shows them to you in order of date, giving you the possibility to easily find an old voice note and share it with other apps.
Update version 1.2.0
-Now with Opus Player you can delete your voice notes without
accessing to a file manager, rather directly in the app.