6 Apr
2013
6 Apr
'13
3:22 a.m.
On Sat, 2013-04-06 at 03:03 +0200, Peder Hedlund wrote:
Quoting Ralf Mardorf
<ralf.mardorf(a)alice-dsl.net>et>:
I know, that's a misunderstanding, perhaps to my broken English. But
there are two channels for stereo and for both channels the data will be
reduced (I avoid to use the word "compressed" in this context). It's
psycho-acoustic data reduction, so how can be ensured that the
psycho-acoustic effect can keep the balance between the two channels,
regarding to the recorded room?
FWIW I'm only experienced with stereo, not
with 2D or 3D and I guess
most engineers are inexperienced with 2D and 3D, however, assumed MP3
can be used for stereo, it would be interesting to know, if MP3 or
another codec with inaudible loss, is able to keep the mix for a real 2D
or 3D recording. I don't know how data reduction does work, but I guess
there's an effect similar to a compressor (the effect app or device).
No, data reduction in MP3, Vorbis, Opus, AAC or any of the other
technologies is not just like a regular compressor in any way, shape
or form.
Neither in the way of a 3:1, soft knee@-18 dB compressor or in the way
of a "repeat this 0101 pattern 24 times" zip file. It's exploiting the psychoacoustical fact that the
sensitivity of our
ears depends a lot on which frequency we're listening to and that a
strong signal in one frequency completely masks a weak signal nearby
to our ears.
So if you have a -20 dB signal at 7kHz at the same time you have a
-5dB signal at 7.2kHz you can discard the former one since we won't
hear it anyway.
The sound of an instrument will be the same as before, but the
impression of it's position in the room might change.
There is an extension to MP3 called MP3 surround which
is able to
handle 5.1 surround sound (2D and 3D are image formats, not audio
formats).
Dimensions are dimensions, also for sound, but a common mistake is that
people already call 2D sound 3D sound.