Audacity Forum

The number of channels available depends on the sound card drivers.

If you look in the "Audio device info" (https://manual.audacityteam.org/man/hel ... evice_info), are there any devices listed that provide 4 recording channels?

After editing and saving (exporting) the file in 2.2.1- I opened the same file in 2.3.2 Do you mean "the same file that you exported from 2.2.1"? If so, I'd recommend that with Audacity 2.3.2, you export a new version of the WAV file (with a new name), and then quit Audacity. Then reopen ...

Hiss cannot be "prevented". There will always be some amount of hiss. Even a copper wire produces a tiny bit of his (very very tiny amount) due to thermal noise. The objective is to prevent "excessive" hiss - to minimise the amount of hiss. The most common cause of excessive his ...

There's a bug in Audacity 2.2.1 that you need to be aware of: If you overwrite a project using "Save Project As..." (rather than the normal "Save Project..."), it can cause data loss. This bug has been fixed and is not present in later versions of Audacity, but in Audacity 2.2.1,...

Dangerous to the file, to the computer, or to the public at large? Perhaps endangering the very fabric of existence... but I doubt it. Worst case is probably that exported audio files from the project are unplayable (corrupt), and then the project crashes and won't re-open without immediately crash...

You can try renaming the files with ".mp4" file extension instead of ".m4a".
Other than that, it's a matter of waiting for Apple to roll out the fix for Windows, or use a different media player.

It looks like Audacity is sending the audio correctly. Perhaps it is muted somewhere else on your system (?)
I don't have a DisplayPort device, so I'm not able to make further suggestions. Perhaps someone else on this forum has experience of DisplayPort devices.

I don't speak Italian.
If you select WASAPI as the "host" in the device toolbar, does that allow you to select more channels?

Which version of Audacity? (look in "Help menu > About Audacity")

Imagine that we can't see your machine, and that we only know what you tell us.
What happens when you select each of the "display port" options as the playback device in the device toolbar?