Digital awful Broadcasting

[Brian Gaff]

I was just flipping through the stations on my DAB the other day, and was
struck by an underlying grotty feel to many stations. I am speaking of the
gritty sound that many, most often talk stations, Have now. Talk radio, to
pick one at random, sounds like one of the lower quality long play modes on
a minidisc. AM was better in my view, assuming you were close to the
transmitter. I'm just guessing that it is part of a reduction in bitrate or
increase in errors inherent in the system.
Even music stations, be they plus or otherwise are not totally immune, but
then I have no way to know what sort of encoding is in use.This distortion
though, seems to also affect other outlets of the same station, as if they
are all distributed in the worst possible system.

I just can't listen to the talk stations any more due to this gritiness.
However its worse I think if you are an ethnic minority, as their stations
even try to play music over it as well. Bah humbug.
Brian

[Woody]

Don't get caught out Brian. Talk Radio (and for that matter GB News
Radio) is DAB+ (DAB PLUS) but at different rates. Talk is 32 kilobits in
stereo, GB News is 24 kilobits mono.

I have also noted that both stations (although more noticeably GB News)
seem to have some sort of muting system so that there is no noise
between speakers or between separate bits of the same speaker. It often
results in loss of the first syllable when the speaker starts talking
and the mute or whatever it is seems to have a relatively slow attack.

I don't notice any issues with grittiness as you report it, but could I
suggest that it may be something to do with distribution? We out here in
the frozen north seem to get clear quality - perhaps there is just too
much infrastructure or distribution noise in London?

Post by Brian Gaff
I was just flipping through the stations on my DAB the other day, and was
struck by an underlying grotty feel to many stations. I am speaking of the
gritty sound that many, most often talk stations, Have now. Talk radio, to
pick one at random, sounds like one of the lower quality long play modes on
a minidisc. AM was better in my view, assuming you were close to the
transmitter. I'm just guessing that it is part of a reduction in bitrate or
increase in errors inherent in the system.
Even music stations, be they plus or otherwise are not totally immune, but
then I have no way to know what sort of encoding is in use.This distortion
though, seems to also affect other outlets of the same station, as if they
are all distributed in the worst possible system.
I just can't listen to the talk stations any more due to this gritiness.
However its worse I think if you are an ethnic minority, as their stations
even try to play music over it as well. Bah humbug.
Brian

[JMB99]

Post by Woody
I don't notice any issues with grittiness as you report it, but could I
suggest that it may be something to do with distribution? We out here in
the frozen north seem to get clear quality - perhaps there is just too
much infrastructure or distribution noise in London?

I can't imagine the distribution degrading the quality?

[Mark Carver]

Post by JMB99

Post by Woody
I don't notice any issues with grittiness as you report it, but could
I suggest that it may be something to do with distribution? We out
here in the frozen north seem to get clear quality - perhaps there is
just too much infrastructure or distribution noise in London?

I can't imagine the distribution degrading the quality?

Of course it doesn't, and the stations are encoded and muxed together
centrally. So the quality is exactly the same whether you're using
Crystal Palace or Bressay.

It has to be that way, because muxes are SFNs

[John Williamson]

Post by Mark Carver

Post by JMB99
I can't imagine the distribution degrading the quality?

Of course it doesn't, and the stations are encoded and muxed together
centrally. So the quality is exactly the same whether you're using
Crystal Palace or Bressay.
It has to be that way, because muxes are SFNs

Do all the stations use the same bit rate on all the transmitters?

I can see no technical reason for that to be the case, and in Brian
Gaff's area, there is a lot more demand for setting up a station than
there is here in the Black Country, which gives an excuse for dropping
the bit rates there.

It may also be the case that Brian has more sensitivity to audio
artifacts than many sighted people.

[Mark Carver]

Post by John Williamson

Post by Mark Carver

Post by JMB99
I can't imagine the distribution degrading the quality?

Of course it doesn't, and the stations are encoded and muxed together
centrally. So the quality is exactly the same whether you're using
Crystal Palace or Bressay.
It has to be that way, because muxes are SFNs

Do all the stations use the same bit rate on all the transmitters?

The same bit rate has to be used on all transmitters that carry the same
mux. In fact the entire encoded transport stream has to be IDENTICAL on
all transmitters, or else the SFN won't work.

If you're taking about the same station on different local muxes, then
that's a different matter, although taking a quick look on Wohnort, even
then the bit rates are the same (probably because the station only wants
to encode itself 'once')

[Scott]

Post by Mark Carver

Post by John Williamson

Post by Mark Carver

Post by JMB99
I can't imagine the distribution degrading the quality?

Of course it doesn't, and the stations are encoded and muxed together
centrally. So the quality is exactly the same whether you're using
Crystal Palace or Bressay.
It has to be that way, because muxes are SFNs

Do all the stations use the same bit rate on all the transmitters?

The same bit rate has to be used on all transmitters that carry the same
mux. In fact the entire encoded transport stream has to be IDENTICAL on
all transmitters, or else the SFN won't work.
If you're taking about the same station on different local muxes, then
that's a different matter, although taking a quick look on Wohnort, even
then the bit rates are the same (probably because the station only wants
to encode itself 'once')

Until very recently Gold in London was 40 kbps and Gold UK was 32
kbps. Now they seem to be equalised.

[J. P. Gilliver]

Post by Mark Carver

Post by JMB99

Post by Woody
I don't notice any issues with grittiness as you report it, but
could I suggest that it may be something to do with distribution? We
out here in the frozen north seem to get clear quality - perhaps
there is just too much infrastructure or distribution noise in London?

I can't imagine the distribution degrading the quality?

Of course it doesn't, and the stations are encoded and muxed together
centrally. So the quality is exactly the same whether you're using
Crystal Palace or Bressay.
It has to be that way, because muxes are SFNs

By "distribution noise", I think Woody meant noise from _other_
distribution networks - such as the mains electricity supply - rather
than the one the listener is trying to receive. In other words, signal
degradation, not coding errors in the first place.

[Pamela]

Post by Woody
Don't get caught out Brian. Talk Radio (and for that matter GB News
Radio) is DAB+ (DAB PLUS) but at different rates. Talk is 32 kilobits
in stereo, GB News is 24 kilobits mono.
I have also noted that both stations (although more noticeably GB
News) seem to have some sort of muting system so that there is no
noise between speakers or between separate bits of the same speaker.
It often results in loss of the first syllable when the speaker starts
talking and the mute or whatever it is seems to have a relatively slow
attack.

My bete noir is the very rapid speech on GB News, and to a lesser extent on
TalkRadio. It certainly makes you pay close attention if you want to follow
the discussion!

Post by Woody
I don't notice any issues with grittiness as you report it, but could
I suggest that it may be something to do with distribution? We out
here in the frozen north seem to get clear quality - perhaps there is
just too much infrastructure or distribution noise in London?

[JMB99]

Post by Woody
I have also noted that both stations (although more noticeably GB
News) seem to have some sort of muting system so that there is no
noise between speakers or between separate bits of the same speaker.
It often results in loss of the first syllable when the speaker starts
talking and the mute or whatever it is seems to have a relatively slow
attack.

Isn't that common with automated presenter operated sources?

[J. P. Gilliver]

Post by JMB99

Post by Woody
I have also noted that both stations (although more noticeably GB
News) seem to have some sort of muting system so that there is no
noise between speakers or between separate bits of the same speaker.
It often results in loss of the first syllable when the speaker starts
talking and the mute or whatever it is seems to have a relatively slow
attack.

Isn't that common with automated presenter operated sources?

AGC to mute background noise when the speaker is not speaking has been
around for decades; however, you'd think that today it would be trivial
to insert a slight delay - half a second ought to be more than enough in
most cases - so that the chopping-off-of-the-first-syllable that Pamela
has noticed could be avoided. Could be either at the presenter end or
the studio end. But obviously isn't being done.

[Pamela]

Post by J. P. Gilliver

Post by JMB99

Post by Woody
I have also noted that both stations (although more noticeably GB
News) seem to have some sort of muting system so that there is no
noise between speakers or between separate bits of the same speaker.
It often results in loss of the first syllable when the speaker starts
talking and the mute or whatever it is seems to have a relatively slow
attack.

Isn't that common with automated presenter operated sources?

AGC to mute background noise when the speaker is not speaking has been
around for decades; however, you'd think that today it would be trivial
to insert a slight delay - half a second ought to be more than enough in
most cases - so that the chopping-off-of-the-first-syllable that Pamela
has noticed could be avoided. Could be either at the presenter end or
the studio end. But obviously isn't being done.

Woody said that, not me. It was attrubuted incorrectly.

[NY]

Post by J. P. Gilliver

Post by JMB99

Post by Woody
I have also noted that both stations (although more noticeably GB
News) seem to have some sort of muting system so that there is no
noise between speakers or between separate bits of the same speaker.
It often results in loss of the first syllable when the speaker starts
talking and the mute or whatever it is seems to have a relatively slow
attack.

Isn't that common with automated presenter operated sources?

AGC to mute background noise when the speaker is not speaking has been
around for decades; however, you'd think that today it would be trivial to
insert a slight delay - half a second ought to be more than enough in most
cases - so that the chopping-off-of-the-first-syllable that Pamela has
noticed could be avoided. Could be either at the presenter end or the
studio end. But obviously isn't being done.

Almost as bad is when AGC mutes significant background noise in a drama,
where the noise is ambient sound (eg birdsong, traffic noise) which is
*wanted* to give atmosphere. There is an episode of Inspector Morse that was
fine on its original ITV broadcast but every time it is shown on ITV3 the
sound is very poor (maybe ITV3's copy was badly copied from the master) and
the background noise in some exterior scenes pulsates every time anyone
speaks - you see the characters walking along talking, and there is absolute
silence except when someone speaks when you suddenly get a blast of birdsong
as well which is not there when no-one is talking - very unnerving.

[Pamela]

Post by Brian Gaff
I was just flipping through the stations on my DAB the other day, and
was struck by an underlying grotty feel to many stations. I am
speaking of the gritty sound that many, most often talk stations, Have
now. Talk radio, to pick one at random, sounds like one of the lower
quality long play modes on a minidisc. AM was better in my view,
assuming you were close to the transmitter. I'm just guessing that it
is part of a reduction in bitrate or increase in errors inherent in
the system.
Even music stations, be they plus or otherwise are not totally immune,
but then I have no way to know what sort of encoding is in use.This
distortion though, seems to also affect other outlets of the same
station, as if they are all distributed in the worst possible system.
I just can't listen to the talk stations any more due to this
gritiness.
However its worse I think if you are an ethnic minority, as their
stations even try to play music over it as well. Bah humbug.
Brian

Years before DAB, I was complaining how radio stations were sounding
distinctly distorted. However it turned out to be some unusual damage to
my hearing from an infection.

[Brian Gaff]

Yes that can happen. I have tinnitus, but that was from being too close to a
couple of lightening strikes in my 30s. It does not impact the definite
grainy feel of the sound. Its a bit like its been recorded on a very bad
tape, you know the sort usually sold at markets.
My guess is its the half sample rate issue you can get on low bit rate
mp3s. These also affect phase between channels too, since they try to make
it sound right on smaller systems.
Brian
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Post by Pamela

Post by Brian Gaff
I was just flipping through the stations on my DAB the other day, and
was struck by an underlying grotty feel to many stations. I am
speaking of the gritty sound that many, most often talk stations, Have
now. Talk radio, to pick one at random, sounds like one of the lower
quality long play modes on a minidisc. AM was better in my view,
assuming you were close to the transmitter. I'm just guessing that it
is part of a reduction in bitrate or increase in errors inherent in
the system.
Even music stations, be they plus or otherwise are not totally immune,
but then I have no way to know what sort of encoding is in use.This
distortion though, seems to also affect other outlets of the same
station, as if they are all distributed in the worst possible system.
I just can't listen to the talk stations any more due to this
gritiness.
However its worse I think if you are an ethnic minority, as their
stations even try to play music over it as well. Bah humbug.
Brian

Years before DAB, I was complaining how radio stations were sounding
distinctly distorted. However it turned out to be some unusual damage to
my hearing from an infection.