LAME 3.98 Beta 6 vs iTunes 7.6.1
Reply #10 – 2008-04-01 00:30:02
OK, I'm getting the consensus that even at moderate compression levels and higher bit rates (i.e. 192kbs VBR High Quality) it is preferable to set a high-frequency cutoff at 16Khz to 18KHz, rather than extend the frequency response to the max. 22,050 Hz. This allows for more accurate MP3 encoding with less "audible" artifacts. Actually 16Khz is FM broadcast quality, which is not bad (from a freq. resp. perspective only!). All this doesn't matter. The only thing which matters is what you hear. Lossy encoding is not about graphs and numbers...... even if it would cut off at 12khz, it wouldnt matter as long as it cannot be heard (it could be, but thats not the point). The reason for why lossy encoders "save" at the ultrahigh frequencies? Well, because: 1. The higher the frequency, the more bits are required for accurate encoding. 2. The higher the frequency, the less audible it is (starting at 15-16khz, humans tend to not hear stuff at all with normal music). BTW: Most unexperiences people highly overestimate their hearing. 16khz to the listener is not "high" frequencies like hihats.... 16khz is way way above that. Normal music content ends at about 13-14khz... everything above that is just faint noise). 3. Resources are not infinit - you have a limited amount of bits, and then need to choose how to distribute them. 1bit spend in one area, is 1bit not spend somewhere else. In other words: adding bits to one area, is the same as taking bits away from another area.