Themis;540053 Wrote:
> In my mind the value of the samples are supposed to represent a sum of
> functions necessary for reconstructing a signal (band-limited) that
> changes in time. In other words, the value of one sample is of interest
> only compared to the values of the two samples that surround it.
>
> A volume, yes, of course. But I can't see how we can manipulate the
> values of the samples with simple operations (subtraction, division,
> etc) while maintaining a coherence in the signal, thus maintaining a
> coherence in the sum of functions. The result can only be an
> approximation.
>
> (The 1-bit was an example)
I did state it earlier... it's one of the basic but hard-to-grasp
concepts of digital audio... there is only one thing to manipulate and
that is simply a stream of numbers that hit the DAC one after another
at a specific rate. Each sample is just a number, represented as a 16
or 24 bit word. Excluding DSP functions that insert/add extra samples,
ALL you can do is make the numbers bigger or smaller (or leave them
alone). Any change you make to the numbers changes the sound.
If you add "1000" to every sample you've increased the level of the
track.
All the audio properties except level are defined by the precise
SEQUENCE of numbers that are the samples.
So:
(in decimal)
0 1 2 3 4 5 6 7 8 9 8 7 6 5 4 3 2 1 would be a trinagular waveform
0 0 0 0 9 9 9 9 0 0 0 0 9 9 9 9 would be a square wave
{before anyone jumps on me - these are only a simple representation!}
and so on. Any sound no matter how complex can be represented by the
correct sequence of numbers.
To perform DSP other than basic level control such as volume or
fade-in/out (e.g. EQ) requires much more complex mathematics than just
adding or subtracting a FIXED number to EVERY sample. The DSP function
determines by how much to alter each sample.
--
Phil Leigh
You want to see the signal path BEFORE it gets onto a CD/vinyl...it
ain't what you'd call minimal...
Touch(wired/XP) - TACT 2.2X (Linear PSU) + Good Vibrations S/W - MF
Triplethreat(Audiocom full mods) - Linn 5103 - Aktiv 5.1 system (6x
LK140's, ESPEK/TRIKAN/KATAN/SEIZMIK 10.5), Townsend Supertweeters, Blue
Jeans Digital,Kimber Speaker & Chord Interconnect cables
Kitchen Boom, Outdoors: SB Radio
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