Jim Lesurf wrote:
In article , DAB sounds worse
than FM wrote:
Jim Lesurf wrote:
In article , DAB sounds
worse than FM wrote:
Jim Lesurf wrote:
In article , DAB sounds
worse than FM wrote:


Because Radios 1 & 2 and all the pop stations have audio
processing applied then the spectrum tends to be wide and flat,
which tends to result in aa lot of remaining frequency
components after the psychoacoustic model has produced the
masking curves to throw away the inaudible subbands.

Is that the case in the timescales relevant for the data reduction
'frames' (or whatever the correct term is)? I can see that R1/2
tend to use audio 'compression' (in the old sense) and this may
work to flatten the medium term power spectrum. However that does
not in itself mean the spectrum is 'white' if it has a finite
number of components. Nor does it necessarily mean that each
individual processed time-frame will have a near uniform power
spectral density. Do you have some data on this relevant to R1/2?


No data; I've just looked at a lot of spectra. I know it's not
white, but it's a hell of a lot flatter and broader for R1/2 than
R3. R3 tends to tail-off quickly, whereas R1/2 tails-off
significantly slower and for the vast majority of the time it goes
right the way up to the brickwall filter.

The difficulty is that doesn't necessarily lead to your conclusion.


Common sense dictates that it does.

I'm afraid that would only be so if the 'common sense' does not take
into acount the distinctions I was outlining. :-) Hence it would be
like the 'common sense' that sometimes causes people to say all kinds
of things which may turn out to be incorrect. I am wary of
conclusions "dictated" by "common sense" as this often turns out to
be a poor guide.


I couldn't give a flying fk whether you're wary of such conclusions or
if you're madly in love with them.


The spectral components present in any time frame may extend across
a wider range, and be more unform in size. But if the *number* of
components that are resolved in the time frame are sigificantly
less, then the 'weeding' process may lose less info. Impossible to
assess this without much more specific info than simply observing a
tendency for the components that are present to have similar
levels, etc.

Hence I think the point you make is certainly an important one, but
it may not establish the conclusion you draw without more specific
evidence.


What I've heard over the last 3 years tell me that I'm right.

Or rather, leads you to *believe* you are right. :-)


Absolutely it does.


Not saying you are wrong. Just saying 'dunno', but 'not proven'
simply from what you have said.


I cannot prove this with absolute certainty, but it's beyond
reasonable doubt IMO.

I note your opinion, but am trying to distinguish between opinions and
matters of fact.


The fact that I cannot prove this does not mean that I am just going to
drop this view; which just happens to be exactly what you would like me
to do.


If you can justify that to yourself as being fair then the only
conclusion I can come to is that you're extremely selfish.

Can't really comment on what may be 'fair' here. Just have an
interest in when the system may show audible problems. Since I
don't listen much to R1/2 (and never on DAB) I can't pass any
comment on them one way or the other.


Well I can, and they sound ****e, and it is unfair that they sound
****e while R3 uses a 50% higher bit rate. Only a fascist would
disagree.

Your comment seem to be in the spirit of the 'Ken Livingstone' school
of scientific discussion. :-)


Suits me.


FWIW in terms of *video* I have certainly seen very 'odd' effects at
times on BBCTV4 via DTTV. e.g. I have DVD+R's of one prom where the
'live' sic broadcast has a picture that 'stutters' throughout a
large part of the broadcast, but where the late-night repeat is
fine. I assume this was variable rate statmux stealing bitrate from
BBCTV4


Probably. The BBC never alter the stat-mux bit rate allocations,
which is incredibly lazy, IMO.


during the evening to give to some other station(s), but a higher
rate being available after midnight for the repeat. Would not
surprise me if similar 'audio' crudities turned up on DAB at times.


I thought you were talking about video?

Depends what comments I made that you are referring to.


Correct me if I'm wrong, but all of this seemed to be to do with
TV/video:

"FWIW in terms of video I have certainly seen very 'odd' effects at
times
on BBCTV4 via DTTV. e.g. I have DVD+R's of one prom where the 'live'
sic
broadcast has a picture that 'stutters' throughout a large part of the
broadcast, but where the late-night repeat is fine. I assume this was
variable rate statmux stealing bitrate from BBCTV4 during the evening to
give to some other station(s), but a higher rate being available after
midnight for the repeat."


I have made
some comments about the sound of R3 on 'Freeview'. I have made some
comments about the sound of BBCTV4 on Freeview. I have also made a
comment about the *video* on BBCTV4 on Freeview. How these may be
related, though, I am unsure.


Well, you were the bloody one making all the various points, so if you
don't know what point you were trying to make then how the bloody hell
should I know?


Only generalisation is that they all
involve data-reduction 'compression' systems to communicate the
information.


Give the man a Nobel prize.

BTW, you seem to be entering pedant mode, again. If at all possible,
please don't enter said mode again. TIA.


--
Steve - www.digitalradiotech.co.uk - Digital Radio News & Info

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