I have three acoustic spectograms of different copies of the same song:
- MP3; 320 kbps; 9.20 MB
- M4A (AAC); 256 kbps; 7.46 MB; Converted from 1. audio file via iTunes
- M4A (AAC); 225 kbps; 6.87 MB
I want to determine which of these copies have the best audio quality. Since human hearing range is commonly considered to be within 20 to 20,000 Hz and that a 16 kHz cut is noticeable in the first two copies I would go with the third audio file harbor a superior audio quality. The 3. audio file kind of uses the human hearing range to the fullest while the first two ones cut off apruptly. This looks very artificial to me.
- Is this correct? Are my assumptions correct?
- Is there a software or a method which compares and finally determines which lossy version is of higher audio quality?
- Can someone give me a profound explanation on how to determine a good 320 kbps MP3 file. (e.g. I get a MP3 which states 320 kbps and I think this is very good quality but do not know how this file got compressed at the first place, taking into consideration that LAME is a superior encoder than Fraunhofer)
- Is it correct that M4A (AAC coding standard) is superior and generally achieves better sound quality than MP3 at the same bit rate?
Please correct me if I am wrong with assumptions. Merci