My explanations must not have been clear.
For example, are you saying your recording looks like this, with the top or bottom of the stereo track a flat line?"
Yes, that is what is happening: Blank bottom track, when recording and playing back the recording.
Yes, it says "stereo" at the left, but there is no track to split if I wanted to, but all I want is both tracks like it was. All my settings are stereo.
If one of your computer speakers is muted, that is what you need to fix. That is not Audacity's fault. Either the speaker connection is loose, or you can go to Windows Sound, Playback tab, and adjust the balance of the channels or unmute the channel that is silent.
Nothing is muted. My problem is that only one track is recording and only one is playing back. One speaker, I presume, is not playing for that reason. Or maybe both Audacity and the speaker are missing the track for the same reason, whatever that may be.
In what way were they "slightly different"? Do you mean they sounded slightly different?
Before I lost the bottom track, the graphics were different to one degree or other, sometimes a lot. I frankly never inspected the sound of each speaker closely enough to determine how different they may be.
If the internet broadcast contains audio where the left and right channels are the same, and your speakers are correct, then it will record like that and it will sound as if it is mono, even if you tell Audacity to record in stereo.
I just want both tracks like I had before, regardless of whether they may sometimes be the same.
The highest resolution the downloader offers is lower than the highest level setting available to stream
Then I suggest you are not using the best possible downloader tool.
I use "Download Youtube Videos As MP4" Firefox addon. It offers MP4 resolutions 360p and 720p if both are available. If 720 is available, then 1080 is also available to view (via cog-wheel icon), but not offered for download. What downloader will do 1080?
I read somewhere that generally Youtube used to correlate higher video resolution to higher audio, but now it is usually separate, so it may make no difference what the video resolutoin is. There is a site that analyzes videos for audio levels, but I'm not sure how to interpret it. I tried to post a link to the web page, but apparently that's not allowed. The page is called "Youtube Info". There, you can paste a Youtube address and hit enter. After the www, it reads h3xed (dot) com (slash) blogmedia (slash) youtube-info. followed by php