sabletones
Joined: 07/03/11
Posts: 165
Loc: uk
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dithering over dither
#971887 - 23/02/12 05:43 PM
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Hi....i've read and re-read the theory of dither. I have a modest but incomplete
understanding of the theory......however, this question is about the 'optional' button i
am confronted with when mixing down work to stereo before producing a CD. I use 24/16 bit
at different times. Most work is currently recordings of choral/orchestral concerts,
sometimes..for example...a Mumford & Sons cover band.
What should i be
considering when faced with the Dither button on my recorder? Why should i activate it
and why should i not?
cheers
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dmills
Joined: 25/08/06
Posts: 2128
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Re: dithering over dither
[Re: sabletones]
#971901 - 23/02/12 06:42 PM
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If you re transferring digitally to a narrower wordlength then dither should be applied
(BUT THIS SHOULD BE AUTOMATIC), I have never really seen the point of offering a on/off
switch for this, it is strictly dependent on the question "is the output wordlength
shorter then the internal precision?"..
The type of dither might be a user
option, but I cannot think of anything sane that has a on/off switch for dither (There
were some very early DAT machines (usually about 13 bits in reality) that did have such a
switch, they generally hit the skip years ago and are not missed).
What
recorder is this?
Regards, Dan.
--------------------
Audiophiles use phono leads because they are unbalanced people!
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Michael Dow
Joined: 28/08/08
Posts: 764
Loc: London
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Re: dithering over dither
[Re: dmills]
#971982 - 24/02/12 10:01 AM
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Well some mastering plugins offer dithering such as waves L2 and then so does the
rendering window of most (probably all) daw's I'd imagine you don't need to
have both engaged but the chances are most people Won't hear the difference in their
home setups or their iPod headphones right?
-------------------- www.myspace.com/michaeldow www.myspace.com/portasoundband
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sabletones
Joined: 07/03/11
Posts: 165
Loc: uk
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Re: dithering over dither
[Re: dmills]
#971985 - 24/02/12 10:19 AM
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Hi Dan, it's a yamaha AW2400
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sabletones
Joined: 07/03/11
Posts: 165
Loc: uk
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Re: dithering over dither
[Re: sabletones]
#971994 - 24/02/12 10:49 AM
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I just watched a You tube video: am i right in thinking - the stereo track will be
automatically dithered at CD burn....the option button i reffered to is offered as part of
mixdown functions.....the video said you should only dither once.....so maybe this button
is an added option for those who know what why and how to go about utilising it? maybe?
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Hugh Robjohns
SOS Technical Editor
Joined: 25/07/03
Posts: 18348
Loc: Worcestershire
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Re: dithering over dither
[Re: sabletones]
#971995 - 24/02/12 10:53 AM
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As Dan says, dither should always be used when the wordlength is being reduced -- so when
going from 24 bits down to 16, for example.
There is no need to use it when
there is no wordlength reduction (eg when transferring a 16 bit source to a 16 bit
destination), but if you did apply dither at that stage you'd just be raising the noise
floor slightly.
If you fail to apply dither when reducing the wordlength then
there is a risk that you will hear distortion and other unpleasant artefacts when the
signal falls to low levels... but if the source material has an inherent noise floor well
above that of the medium (ie ~90dB for a 16 bit system) the chances are you won't notice
whether dither is applied or not!
But the safest approach is always to apply
dither when reducing the wordlength... and try to apply it only in one place!
hugh
--------------------
Technical Editor, Sound On Sound
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sabletones
Joined: 07/03/11
Posts: 165
Loc: uk
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Re: dithering over dither
[Re: sabletones]
#972002 - 24/02/12 11:22 AM
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thanks for that. I have asked Yamaha what i hope is a sensible question: If the Dither
button is 'OFF' on the mixdown page....does the recorder truncate the data or
automatically dither at this stage....when a 24 bit song is dropped to 16 bit for
recording to CD.
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Hugh Robjohns
SOS Technical Editor
Joined: 25/07/03
Posts: 18348
Loc: Worcestershire
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Re: dithering over dither
[Re: sabletones]
#972024 - 24/02/12 12:40 PM
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It will truncate. I don't know why Yamaha provide the ability to turn dither off... but
they always have!
Hugh
--------------------
Technical Editor, Sound On Sound
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sabletones
Joined: 07/03/11
Posts: 165
Loc: uk
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Re: dithering over dither
[Re: sabletones]
#972206 - 25/02/12 11:02 AM
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So....in my own words (always a good test).....if i optimise my recording level at 24 bit
(and i am suggesting this is where 'I' get the most benefit of 24 bit recording)....&
due to the fact that the upper Bits of the 24 show a mathematical diminishing return (do
they?)
....when my machine truncates the data on mixdown to CD/16bit a goodly
proportion of the bits truncated will effectively be redundant or insignificant......(also
being mindful of the inherent noise floor alluded to here and elsewhere)......Redundant or
insignificant both in terms of the physics and the real world placement of my product in
its rather low key but discerning environment....or....shall i skulk away now?
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