In article ,
Lord Hasenpfeffer wrote:


This is true. It does amaze me. Only now I know more about why this is
the case. The original CD source is "unnormalized" in my sense of the
term. The MP3 is made from a normalized WAV. In in general, most
people (including me) tend to believe that louder is better ... because
with loudness comes clarity.

This remains... an MP3 made from an older, quieter, unnormalized WAV
sounds poor to me compared to an MP3 made from a normalized one at the
same level of volume. I frequently listen to my MP3s in random shuffle
mode. Without "normalization", "remastered MP3s" sound are louder and
clearer sounding that "unremastered MP3s". Therefore, it is useful for
me to normalize older WAVs so that all of my MP3s have a nice, even
loudness. If I don't the older MP3s sound like crap in comparison the
newer "remastered" ones.

The real question, then, is "Where does the enhanced sense of clarity
come from?" Or, conversely, "Why do the MP3 encodings made from
lower-level CDs sound poorer to you, and why?"

I can see at least two possible hypotheses:

Hypothesis 1: the _relative_ amount of frequency content in the two
MP3 versions is identical, to within the inevitable low-level errors
implied by any coding system. Or, in other words, the lower-level
(duller-sounding-to-you) MP3 would sound identical to the higher-level
(clearer-sounding) MP3, if you simply turned up the volume a bit. The
differences in how you perceive the two aren't due to the actual
content of the MP3, only to the playback amplitude.

You might be perceiving the two as substantially different either due
to the well-known Fletcher-Munson effect: your ears' relative
sensitivities to bass and treble fall off faster than their
sensitivity to midrange, as the volume is reduced, and thus quieter
signals tend to sound as if they lack both bass and treble.

Or, it might be a masking and ambient-noise effect. If you typically
listen to MP3s in conditions of high ambient noise (office, car,
outdoors, etc.) then more of the lower-level-MP3 playback would be
drowned out by ambient noise, making it sound less clear.

The cure for this would be simply "Turn up the volume during playback."

Hypothesis 2: the MP3s encoded from lower-amplitude (non-normalized)
WAV inputs are actually, and significantly different than their
higher-amplitude cousins in ways other than just amplitude. Possibly
some frequencies are missing (excessive masking, or sounds below
threshold), possibly some frequency bands are less accurately encoded
and have a higher noise level.

This would suggest that the MP3 encoder you are using is less than
optimal. Possibly it has a poorly-set threshold detector, which is
sensitive only to the absolute signal level and not to the relative
levels. Possibly one of its other encoder or bit-allocation
algorithms is misbehaving, and is dedicating larger portions of the
available bit bandwidth to certain frequencies and is being forced to
discard other bands for lack of sufficient bit-reservoir in the
encoding.

The cure for this would be "Use a better encoder, or better settings
for the one that you have."

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
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