A Couple Audiophile Questions

Seems to me 'fidelity' (faithful) would be a reproduction of music that sounds as close to how it sounded in that room at that moment.  

 

Depends on the situation I suppose. Of course that doesn't mean that an audiophile isn't educated on this file format. It would be like a 5 star Michelin chef grabbing a burger and fries at a fast food joint. Counterintuitive to the subject but not an impossibility.

Hi level mp3's for me also, however recently I had to bring down some files for the YGDRASIL JOURNAL OF POETIC ARTS edition of AUDIO poetry, due to the size, and to ensure that it allowed things to fit properly at the National Library of Canada.

The old Space Pirate Radio shows that I have (going back as far as 1974) ended up on MP3's on the highest setting, which makes these very long, since the tapes I used at the time (Maxell and TDK) were all 120's to ensure more music and less breaks. IF, I take any of those shows to Audacity (let's say) and redo any of these files to a lesser setting, IT IS VERY NOTICEABLE. But not enough for you not to be able to enjoy the show or that particular hour.

You can check you this article that compares them...

Basically, the AAC at 128 kbps and MP3 at 320 kpbs have about the same noise spectrum (noise floor around -90 dB according to Figures 6 and 7 of the attached article). AAC, however, "shapes" the noise, so it is 10 dB higher above 6 kHz. The AAC engineers claim your ears are less sensitive there, so it doesn't matter. However, I can often hear the difference. The AAC at 128 kbps encodes smaller than the MP3 at 320 kbps, so you save storage space. At the same bit rate, AAC 320 beats MP3 320, but the noise "shaping" is much more apparent (Figure 8).

Audio quality is all about your perception. That's why many people prefer the sound of vinyl, while others claim CDs sound better to their ears. If you can't hear the difference after encoding (or re-encoding), it really doesn't matter which codec or bit rate you choose.