You should uncheck "joint stereo" when you encode.
I wasn't specifying a particular codec or the options of a particular codec. Your assumptions are incorrect. Your statement is also an implicit unfounded assertion. Your short response is in fact an aggregation of logical fallacies.
Worse is that you only (and fallaciously) address
only my mention of stereo image while neglecting to consider
every other kind of change that can arise from lossy audio compression. That is an
enormous evasion.
Again: I can 100% guarantee that I will never hear my music collection at anything less than the best possible quality available to me.
You cannot say the same if your collection is lossily compressed from your source. The best you can be sure of is that under the particular conditions under which you made comparisons you failed to notice any difference for the particular samples you compared. The things you cannot claim include:
"The compressed audio will also sound identical to me on any other playback hardware I might use."
"The compressed audio will also sound identical to any other person who makes the same comparison."
"I noticed each and every difference (if any)."
"I know for sure that my ears are not much different from simple measuring instruments and that sound does not affect me unless I am consciously aware of it."
"I only perceive sound via my ears. When I listen for differences or artefacts I definitely don't need to consider the various ways my mind and body respond to audio both within and beyond the known audible range."
"Personally, my echoic memory is so good that to me listening to different versions of the same track in quick succession is no different to looking at two versions of a picture and spotting the differences."
Nobody can honestly and truthfully claim those things. But I can honestly and truthfully state that when I listen to my lossless music collection " I can 100% guarantee that I will never hear my music collection at anything less than the best possible quality available to me."
I don't need any riders, caveats, exceptions, claims of exceptional ability or hardware, testing prowess, authority based on number of albums, biological capacity, age, experience, or any of the other stuff that gets presented. I
know my music collection sounds exactly as good as it can. You
claim yours does.