Since the distortions of terrestrial FM and perceptual coding (like MP3) are so different, it's very difficult to draw equivalences. It is better to loose some bandwith, or have some wierd digital distortion? It's a difficult question to answer.
I'd much rather listen to a 8kHz bandwidth, nicely encoded signal than a 20kHz bandwith terribly encoded signal. So, if you want, say, 64kbps for some reason, I've found it's much better to downsample from 44100 to maybe 8000, then encode, rather than try to use a low bitrate at high sample rate. The difference between 8000 and 44100 seems like a *TON*, and it is a lot, but not as much as you think. Since you hear logarithmically, you're really talking about about a 2.5 octave difference. You hear a total of about 10 octaves (from 20 to 20000 Hz), so you're only knocking off the top 25% of your hearing range. Bottom line is, the 'FM equivalent' or 'AM equivalent' are really just best guesses, and not something you can count on. In order to get real, quantitative comparisons, you need to do MOS testing, which is pretty expensive and time consuming. http://en.wikipedia.org/wiki/Mean_opinion_score I bet somebody's done it, I just don't have the results handy. -- ccrome2 Caleb Crome Sr. Hardware Engineer Logitech SMBU (i.e. the Squeezebox people) <B>The future is here. It's just not widely distributed yet.</B> <I>-William Gibson</I> ------------------------------------------------------------------------ ccrome2's Profile: http://forums.slimdevices.com/member.php?userid=18023 View this thread: http://forums.slimdevices.com/showthread.php?t=67502 _______________________________________________ Radio mailing list Radio@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/radio
