This is the quality comparison between Purchased M4A iTunes, Apple Music Rip & Purchased M4A to MP3 converted file @ 320Kbps CBR for the track “Without You by Hadas shor“
We purchased the file (US Store), We also ripped the same track from Apple Music (Using third-party application), We converted the Purchased M4A file to MP3-320Kbps and compared all three files in Spek. Results are as following.
- The left window shows spectrum graph for Purchased AAC M4A iTune file.
- The middle one also shows m4a file which was ripped from Apple Music service using third-party software.
- The right window shows graph for MP3 file which was converted (to MP3 CBR-320Kbps) from purchased M4A file.
P.S. The sound quality of each file was pretty nice 😉
Normally people think that the highest is the best, but reality is not what it seems.
Infact middle graph hits the peak but its not the best. Because the section of spectrum which hits the top is really quiet which is even inaudible. So the audible part cuts off at 20kHz, in which Purchased m4a file is better at giving more audio details.
The right window represents MP3 320Kbps file which gives a flat cut off at 20kHz, the reason is mp3 is capable of encoding files at 20kHz and at 320Kbps it retains the max possible audio details. Even though its lossy but still it is better than Converted M4A file. So the conclusion is: Purchased M4A from Store is best. At this point you may think if M4A is best then why do we upload MP3 320Kbps file.
Comparison between Ripped M4A/Matched M4A/Purchased M4A files.
Conclusion: Ripped M4A file is lossy, So ALAC file directly downloaded from Apple is better.
Conclusion: Matched M4A file and Purchased M4A file are identical and have same audio quality. So there is no quality issue at all if you got any of these.
Why do we upload MP3 files ?
The reason is : MP3 format is supported by almost every multimedia device, and its pointless to say that mp3 is low quality as practically human ear is capable of hearing frequency 20Hz to 20kHz, so quality b/w m4a & mp3 at 20kHz is equivalent. But again it depends upon how efficiently the mp3 file was encoded. Sometimes mp3 file shows 320kbps bitrate but its audio quality is poor, the reason maybe the source of track is not iTunes, it maybe converted from video, or upscaled to increase bitrate virtually. Sometimes quality is bad due to lack of mastereing skills of artist.
That was little explanation of how source of audio, format & encoding methods affect audio quality and again it depends upon many factors.