Description
Contrary to popular belief, deafening/self-deafening (the gray deafened icon) does NOT prevent a bot from receiving audio, and does not reduce network bandwidth. Only server-deafening (the red deafened icon) actually prevents a bot from listening to you.
You may have seen that Discord Support claims otherwise:
Hi, please, I'd like some "official" or direct statement, that this musicbot server deafening itself does actually have any effect on the bandwidth it uses
Hello,
thank you for your patience.
To answer your question: Yes, it has an impact and helps us save bandwidth in voice channels.
Unfortunately, we cannot provide you with any more information. But please let us know if you have any further questions about the app! :)
However, Discord Support's answer doesn't help us. The original question was in regards to 'server deafening' (red deafen), which many people might mistake with 'self deafening' (gray deafen). Monitoring network traffic reveals that audio is still being received while deafened, and in theory could be recorded. See this test performed by @MichailiK:
discord.deafen.as.a.bot.mp4
Notice how Network: rx: (received data) continues to fluctuate (as expected when receiving audio) until the bot is server-deafened. When the deafened icon is gray, the bot is still receiving audio packets. When it is red, it has actually stopped receiving audio, as the Network: rx: drops to zero.
Because of this issue, we have reverted a recent change to JMusicBot self-deafening, as it doesn't achieve the bandwidth-reduction that we had originally hoped. We hope that this issue will be resolved on Discord's end at some point. If we do make other deafen-related settings in the future, we will need to make sure that it is clear that as of right now, self-deafening (gray deafen) is purely cosmetic and doesn't change any functionality of the bot.