DVD-Software.info

[Ruud Broens]

"Stewart Pinkerton" <patent3@dircon.co.uk> wrote in message
news:8393t092nimo9k177d9r4u1iap9q28mkas@4ax.com...
: On Fri, 24 Dec 2004 16:23:16 +0100, "Ruud Broens" <broensr@wanadoo.nl>
: wrote:
:
: >"Stewart Pinkerton" <patent3@dircon.co.uk> wrote in message
: >news:i9ogs0hml3spoccf156qc705hc0mk0sh0u@4ax.com...
: >: The EEs already know this. That's one reason why dithering is an
: >: *essential part* of any digital system - it retains signal detail
well
: >: below the wideband noise floor.
: >:
: >: >We are much more sensitive to coherent sound. A fixed tone such as
a
: >: >PS harmonic can be heard at lower levels than noise. We also pick
: >: >out what our minds are alert to. Distortion is coherent, and some
: >: >forms may be alarming.
: >:
: >: Indeed so, and the established limit for this is some 15-20dB below
: >: the wideband noise floor (it has to do with the bandwidth of our
: >: multiple aural receptors, much like the 'bins' in a FFT analyser).
: >: Also, the absolute threshold of hearing is well established at 0dB
SPL
: >: (indeed, that's *why* it's 0dB!). If we have a system which plays
at
: >: an average level of say 85-90dB SPL (pretty darned loud!), and we
have
: >: a noise floor 80dB below this, with no distortion artifacts above
the
: >: noise floor (any decent 60-watt SS amp, and a few good valve ones),
it
: >: follows that there will be *zero* audible distortion from the
: >: amplifier at normal replay levels.
: >:
: >: It also follows that whatever the SET boys are hearing, it has
nothing
: >: to do with a 'cleaner' signal......................
:
: >Hm, not convinced, i'm afraid :)
:
: No problem, the truth will remain, regardless of your beliefs! :-)
:
: >why would a truely down to the lsb linear DA + amp
: >pumping out 20 or more bit wide @ 192 kHz
: >*need* dithering, Stewart ?
:
: It wouldn't, because DACs don't use dither.
:
: *All* ADC systems need dithering, otherwise they are broken. The
: sampling rate is irrelevant, and one could certainly argue that a true
: 20-bit system is *self* dithering due to analogue noise levels, but
: that's a different matter.
:
: >Oh, btw,
: >even those signals that -by themselves- are below the
: >energy level required for detection
: >*can* be perceived.
: >How ?
:
: Because they are only below the *wideband* noise floor. So long as
: they are above the narrow-band noise floor that equates to the comb
: receptor bandwidth of the frequency to which we're listening, we can
: hear them. We are also able to dig a little deeper when the signal is
: periodic, as we can average out the noise and pick up a signal even a
: little below this narrow-band noise floor. Old-time Morse Code radio
: operators were reputed to be the best at this, along with submarine
: 'phones'.
: --
:
: Stewart Pinkerton | Music is Art - Audio is Engineering

that will do
sampling rate is *hardly* irrelevant, though :)
as to my beliefs..

when you're with tech's, u need tech-appeal
when you're with artists, u need art-appeal
when you're with the opposite sexe..
...you need a whole lot more :-))))

happy ny , london, scotland & everywhere else,
Rudy