recorded to exported audio discrepancy

[herrberr]

Good evening everyone,
I've recently downloaded Audacity to be able to record online academic classes. I guess I grasped the basic concept of loopback-recording but while I was playing around with mock-recordings for the real thing tomorrow, I realized that the exported audio (mp3) has somewhat lower quality than the original recording.
What I mean is that the project opened in Audacity has the same quality as the original audio, but after the export the resulting mp3 has a lower quality, the sound is less "crisp". Is it working as intended or am I missing something?
Sorry for the dumb question, but it's late night and have spent a few hours trying to find a good program to record the above-said classes and it was harder than expected. I skimmed through the wiki but I don't even know what the problem is about, it's my first approach to this kind of software.

[DVDdoug]

MP3 is lossy compression but the higher quality settings can often sound identical to the original.

What settings did you use? Particularly the "Quality" or "Bit Rate" setting?

Did you do any "processing", like using the Graphic Equalizer?

...If you boost the level above 0dB (peak) you can get clipping (distortion) in the exported file. Audacity won't clip "internally" so you might not hear the distortion in Audacity if the volume isn't all the way up, but the exported file can be clipped.

Also, if you compress to MP3 more than once (if you open an MP3 and then re-export it) "damage" accumulates.

[herrberr]

Thanks for the attention Doug,
I've attacched a shot of the quality settings I'm using since I wouldn't know which parameter affects conversion the most.
Also I'm not using any plugin, it's plain "vanilla" Audacity.
What puzzles me is that the recording done with the loopback setting sounds exactly the same as the original audio, but something is lost in the exportation.

[steve]

I've attacched a shot of the quality settings

That looks perfect.

The settings for MP3 encoding quality are in a different place. They appear after you select "File menu > Export > Export as MP3".
See here: https://manual.audacityteam.org/man/mp3 ... tions.html

For good quality stereo audio, the MP3 Quality setting must be at least 128 kbps (preferably higher). The default "standard preset" is shown here and is expected to provide good quality results: https://manual.audacityteam.org/man/mp3 ... tions.html

[herrberr]

Thanks Steve, those hints definitely pointed me at the right direction, I didn't notice I could choose the kbps rate while exporting, that really solved my issue. Also the program is really useful and handy for the online classes, it was kinda easy to trim the recording and delete unwanted parts. I guess the user manual will be enough from now on