Voice clips are a very important feature in the app. But I think there are some advantages already used in other messengers such as WhatsApp or Telegram and they are the following:
When listening to a voice clip, when you bring the phone to your ear, it should be heard as a phone call, when removing it, listening to the speaker again is really comfortable. This can be done, I imagine, taking advantage of the proximity sensor that all mobiles bring to turn off the screen when it is worn to the ear and called.
When multiple voice clips are received, it is very convenient that when you play one, the rest continue to be listened to in series. This way we avoid having to constantly play. It is very useful also in case you want to listen to the clips from the ear.
It would be very convenient to also have information in the voice clips about the time that they last, or some information like the one that I show in the image, that allows us to identify them later. Well, when receiving several it is important to differentiate them.
This is all! Cheers!!!