Are you a mind reader ?
Because I thought to make a post exactly like yours but describing another ( and longer and probably more boring ) procedure.
During the last X-Mas I got lost two nights with a youtube search of some music rarities. After finding something interesting , I tried to record them but without success because the fu**ing proprietary youtube player locks audio device(s). I had success with rawrec
(actually unmantained) which is a commandline tool that can record sounds directly from /dev/dsp in raw 16 bit PCM at 44.100 Hz ( anyway man pages should help for recording in different format/frequency )
Then I've imported the records in audacity ( which has a function for importing raw PCM ) , normalized the tracks , did other tunes and of course added to some mono tracks the same fake-stereo effect first by separating LEFT and RIGHT channels and then by appending 25 msec of silence at the beginning of the left track :D ... a very OLD-STYLE stereo effect
The true stereo effect is not so different : the only difference is that in a multitrack recording enviroment ( professional studio ) you can apply the delay/reverber only to the significant tracks : mainly voices and mid-frequency instruments - eg guitar - ... the other frequencies are usually not treated because our hearing is not sensible to stereo effect of low or very low frequencies ( that's why usually a single subwoofer is enough for reproducing low frequencies in HI-FI ) and of the high - very high frequencies .
To be complete , our hearing is usually not sensible to sounds lower than 20Hz and higher than 20000 Hz ( strictly dependant of personal sensitivity : there's ppl reported to be able to hear lower sounds than 20 Hz and higher than 20000 till 25000 Hz or so )
EDIT : after editing the tracks with audacity I've exported them in WAV 16bit PCM and then converted them in MP3 with lame by command live for the maximum "fidelity" .. :D
lame -m s -q 0 -b 320 "track.wav" "track.mp3"
lame --longhelp for a full description of the command line options.