Classic 'FM' (DAB)

[Scott]

Is it possible Classic has increased the volume or changed the codec
as 9 on the the bedside radio seems louder? Maybe it is because I got
the wax removed from my ears :-)

[Max Demian]

Post by Scott
Is it possible Classic has increased the volume or changed the codec
as 9 on the the bedside radio seems louder? Maybe it is because I got
the wax removed from my ears :-)

I expect they've increased the (dynamic range) compression.

I prefer Radio 3 which has none that I am aware of.

[NY]

Post by Max Demian

Post by Scott
Is it possible Classic has increased the volume or changed the codec
as 9 on the the bedside radio seems louder? Maybe it is because I got
the wax removed from my ears :-)

I expect they've increased the (dynamic range) compression.
I prefer Radio 3 which has none that I am aware of.

Depends how you listen. If you listen on headphones, or on speakers in a
quiet room where you won't disturb other people, you want as little
compression as possible to give the full dynamic range, especially for
classical music. But if you listen on a small radio in the kitchen as you
are cooking, or you listen in the car where there's road noise in the
background, the compression of Classic FM is actually a bonus so you can
hear the quiet bits over the background noise without blasting your earwax
out on the crescendos (crescendi?). Thern there is the matter of whether you
want to hear full concertos with all their movements, or the best, most
tuneful and most well-known extracts. I feel an Inspector Morse to Sergeant
Lewis put-down coming on ;-)

[Liz Tuddenham]

Post by NY

Post by Max Demian

Post by Scott
Is it possible Classic has increased the volume or changed the codec
as 9 on the the bedside radio seems louder? Maybe it is because I got
the wax removed from my ears :-)

I expect they've increased the (dynamic range) compression.
I prefer Radio 3 which has none that I am aware of.

Depends how you listen. If you listen on headphones, or on speakers in a
quiet room where you won't disturb other people, you want as little
compression as possible to give the full dynamic range, especially for
classical music. But if you listen on a small radio in the kitchen as you
are cooking, or you listen in the car where there's road noise in the
background, the compression of Classic FM is actually a bonus so you can
hear the quiet bits over the background noise without blasting your earwax
out on the crescendos (crescendi?). Thern there is the matter of whether you
want to hear full concertos with all their movements, or the best, most
tuneful and most well-known extracts. I feel an Inspector Morse to Sergeant
Lewis put-down coming on ;-)

A long time ago, when a compressor was a large and expensive piece of
kit, it made sense to add compression (if any) before the transmitter.
Nowadays it would be a trivial matter to build a variable compressor
into every radio, so that the user could choose the degree of
compression, depending on circumstances and personal preference.

[Max Demian]

Post by Liz Tuddenham

Post by NY

Post by Max Demian

Post by Scott
Is it possible Classic has increased the volume or changed the codec
as 9 on the the bedside radio seems louder? Maybe it is because I got
the wax removed from my ears :-)

I expect they've increased the (dynamic range) compression.
I prefer Radio 3 which has none that I am aware of.

Depends how you listen. If you listen on headphones, or on speakers in a
quiet room where you won't disturb other people, you want as little
compression as possible to give the full dynamic range, especially for
classical music. But if you listen on a small radio in the kitchen as you
are cooking, or you listen in the car where there's road noise in the
background, the compression of Classic FM is actually a bonus so you can
hear the quiet bits over the background noise without blasting your earwax
out on the crescendos (crescendi?). Thern there is the matter of whether you
want to hear full concertos with all their movements, or the best, most
tuneful and most well-known extracts. I feel an Inspector Morse to Sergeant
Lewis put-down coming on ;-)

A long time ago, when a compressor was a large and expensive piece of
kit, it made sense to add compression (if any) before the transmitter.
Nowadays it would be a trivial matter to build a variable compressor
into every radio, so that the user could choose the degree of
compression, depending on circumstances and personal preference.

Which most car radios have I think.

And I don't see why compression should require "large kit". It's just
AGC I would have thought. And Dolby NR uses compression, just that it
expands on playback, and that has been around donkey's years.

[J. P. Gilliver]

Post by Max Demian

Post by Liz Tuddenham

Post by NY

Post by Max Demian

Post by Scott
Is it possible Classic has increased the volume or changed the codec
as 9 on the the bedside radio seems louder? Maybe it is because I got
the wax removed from my ears :-)

I expect they've increased the (dynamic range) compression.
I prefer Radio 3 which has none that I am aware of.

Depends how you listen. If you listen on headphones, or on speakers in a
quiet room where you won't disturb other people, you want as little
compression as possible to give the full dynamic range, especially for
classical music. But if you listen on a small radio in the kitchen as you
are cooking, or you listen in the car where there's road noise in the
background, the compression of Classic FM is actually a bonus so you can
hear the quiet bits over the background noise without blasting your earwax
out on the crescendos (crescendi?). Thern there is the matter of whether you
want to hear full concertos with all their movements, or the best, most
tuneful and most well-known extracts. I feel an Inspector Morse to Sergeant
Lewis put-down coming on ;-)

A long time ago, when a compressor was a large and expensive piece of
kit, it made sense to add compression (if any) before the transmitter.
Nowadays it would be a trivial matter to build a variable compressor
into every radio, so that the user could choose the degree of
compression, depending on circumstances and personal preference.

I remember - I think '70s or '80s - someone (I'm pretty sure it was
Blaupunkt) sold a car radio with compression; I can't remember whether
it was user-controllable or not, or if so whether it was just an on/off
option. It seemed to me an excellent idea for car radios, but AFAIK
nobody else offered it and I haven't heard of it since.

Post by Max Demian
Which most car radios have I think.

I don't ever remember hearing of such, apart from the above example -
certainly I've never seen mention of it in the either instructions or
advertising copy for them.

Post by Max Demian
And I don't see why compression should require "large kit". It's just
AGC I would have thought. And Dolby NR uses compression, just that it
expands on playback, and that has been around donkey's years.

To do it in a way that wouldn't be obvious might require a bit more kit
than a plain AGC: I remember when I was more of a radio amateur
occasionally coming across someone who had vicious AGC, and it rendered
them tiring to listen to, and sometimes quite hard to understand. Ditto
some cassette recorders with it produced something horrible too. Though
I agree with Liz that nowadays it shouldn't involve much if anything
(probably digital domain in many cases).

[MB]

Post by Liz Tuddenham
A long time ago, when a compressor was a large and expensive piece of
kit, it made sense to add compression (if any) before the transmitter.
Nowadays it would be a trivial matter to build a variable compressor
into every radio, so that the user could choose the degree of
compression, depending on circumstances and personal preference.

I doubt whether many would pay more a radio with adjustable compression.

Not something I have checked but I suspect that the majority of radios
have no tone controls and if they do then will be rarely used.

[J. P. Gilliver]

Post by MB

Post by Liz Tuddenham
A long time ago, when a compressor was a large and expensive piece of
kit, it made sense to add compression (if any) before the transmitter.
Nowadays it would be a trivial matter to build a variable compressor
into every radio, so that the user could choose the degree of
compression, depending on circumstances and personal preference.

I doubt whether many would pay more a radio with adjustable compression.

If suitably marketed, I think it would influence enough people - not
necessarily make them pay more, but make them select one that had it
over one that didn't. Especially if the term wasn't used - "help you
hear the quiet bits without the loud bits blasting you", probably with
some spurious new name: "Acme's special 'hushboost' circuitry helps you
...".

Post by MB
Not something I have checked but I suspect that the majority of radios
have no tone controls and if they do then will be rarely used.

In the case of car ones, certainly, if they're there they're buried in a
menu structure. I think you're right for domestic trannies.

[Roderick Stewart]

Post by Liz Tuddenham
A long time ago, when a compressor was a large and expensive piece of
kit, it made sense to add compression (if any) before the transmitter.
Nowadays it would be a trivial matter to build a variable compressor
into every radio, so that the user could choose the degree of
compression, depending on circumstances and personal preference.

Even better to build an expander into every radio, or every radio that
hi-fi enthusiasts were willing to pay extra for. Compress the signal
before transmission to a level that doesn't sound too offensive if
nothing is subsequently done to it, so it will work with existing
simple radios that don't have the extra circuitry.

The audio data could be accompanied by metadata to specify exactly how
the original dynamic range is to be restored.

The broadcasters could start tomorrow without any disruption to users.
Nobody would need to buy any new equipment if they didn't want to.

Rod.

[Scott]

On Sat, 03 Jun 2023 09:49:08 +0100, Roderick Stewart

Post by Roderick Stewart

Post by Liz Tuddenham
A long time ago, when a compressor was a large and expensive piece of
kit, it made sense to add compression (if any) before the transmitter.
Nowadays it would be a trivial matter to build a variable compressor
into every radio, so that the user could choose the degree of
compression, depending on circumstances and personal preference.

Even better to build an expander into every radio, or every radio that
hi-fi enthusiasts were willing to pay extra for. Compress the signal
before transmission to a level that doesn't sound too offensive if
nothing is subsequently done to it, so it will work with existing
simple radios that don't have the extra circuitry.
The audio data could be accompanied by metadata to specify exactly how
the original dynamic range is to be restored.
The broadcasters could start tomorrow without any disruption to users.
Nobody would need to buy any new equipment if they didn't want to.

Would DAB be able to support this within the existing bitrate?

[Roderick Stewart]

On Sat, 03 Jun 2023 10:06:09 +0100, Scott

Post by Scott
On Sat, 03 Jun 2023 09:49:08 +0100, Roderick Stewart

Post by Roderick Stewart

Post by Liz Tuddenham
A long time ago, when a compressor was a large and expensive piece of
kit, it made sense to add compression (if any) before the transmitter.
Nowadays it would be a trivial matter to build a variable compressor
into every radio, so that the user could choose the degree of
compression, depending on circumstances and personal preference.

Even better to build an expander into every radio, or every radio that
hi-fi enthusiasts were willing to pay extra for. Compress the signal
before transmission to a level that doesn't sound too offensive if
nothing is subsequently done to it, so it will work with existing
simple radios that don't have the extra circuitry.
The audio data could be accompanied by metadata to specify exactly how
the original dynamic range is to be restored.
The broadcasters could start tomorrow without any disruption to users.
Nobody would need to buy any new equipment if they didn't want to.

Would DAB be able to support this within the existing bitrate?

Given that DAB is capable of bitrates up to several hundred kb/s and
normally transmitted with considerably lower ones, without knowing the
precise details I would guess it probably could. Metadata that simply
controlled gain wouldn't need as much bandwidth as the audio itself.

Rod.

[MB]

Post by Roderick Stewart
Given that DAB is capable of bitrates up to several hundred kb/s and
normally transmitted with considerably lower ones, without knowing the
precise details I would guess it probably could. Metadata that simply
controlled gain wouldn't need as much bandwidth as the audio itself.

You need to get receivers on the market and for that you need standards
to be agreed, that takes time.

Then you need to convince manufacturers that there is a demand for it
etc etc.

[Roderick Stewart]

Post by MB

Post by Roderick Stewart
Given that DAB is capable of bitrates up to several hundred kb/s and
normally transmitted with considerably lower ones, without knowing the
precise details I would guess it probably could. Metadata that simply
controlled gain wouldn't need as much bandwidth as the audio itself.

You need to get receivers on the market and for that you need standards
to be agreed, that takes time.
Then you need to convince manufacturers that there is a demand for it
etc etc.

Inded, but advertisers are very good at selling the public things they
don't really need if there's money to be made.

Rod.

[tony sayer]

In article <u5f1l0$3hd16$***@dont-email.me>, MB <***@nospam.net> scribeth
thus

Post by MB

Post by Roderick Stewart
Given that DAB is capable of bitrates up to several hundred kb/s and
normally transmitted with considerably lower ones, without knowing the
precise details I would guess it probably could. Metadata that simply
controlled gain wouldn't need as much bandwidth as the audio itself.

You need to get receivers on the market and for that you need standards
to be agreed, that takes time.
Then you need to convince manufacturers that there is a demand for it
etc etc.

Plus do serious classical listeners take Classic fm that seriously?..

[Mary Wolstenholme]

Post by tony sayer
thus

Post by MB

Post by Roderick Stewart
Given that DAB is capable of bitrates up to several hundred kb/s and
normally transmitted with considerably lower ones, without knowing the
precise details I would guess it probably could. Metadata that simply
controlled gain wouldn't need as much bandwidth as the audio itself.

You need to get receivers on the market and for that you need standards
to be agreed, that takes time.
Then you need to convince manufacturers that there is a demand for it
etc etc.

Plus do serious classical listeners take Classic fm that seriously?..

I find Classic FM easy to recieve. I listen to it. I hate
adverts and so I don't listen to it for long.

[Scott]

On Tue, 06 Jun 2023 15:19:27 +0100, Mary Wolstenholme
<***@easynn.com> wrote:
[snip]>

Post by Mary Wolstenholme
I find Classic FM easy to recieve. I listen to it. I hate
adverts and so I don't listen to it for long.

I think there are fewer adverts at off-peak times. I have heard them
say there will be x minutes (maybe an hour) uninterrupted.

[MB]

Post by Scott
I think there are fewer adverts at off-peak times. I have heard them
say there will be x minutes (maybe an hour) uninterrupted.

Presumably like TV and put out more adverts when more viewers then
ensure the average complies with regulations by having few adverts when
not many viewers.

Unsurprisingly not being done for the benefit of the viewer or listener!

[Scott]

Post by MB

Post by Scott
I think there are fewer adverts at off-peak times. I have heard them
say there will be x minutes (maybe an hour) uninterrupted.

Presumably like TV and put out more adverts when more viewers then
ensure the average complies with regulations by having few adverts when
not many viewers.
Unsurprisingly not being done for the benefit of the viewer or listener!

It benefits me as I usually listen in bed last thing at night :-)

[Woody]

Post by Scott

Post by MB

Post by Scott
I think there are fewer adverts at off-peak times. I have heard them
say there will be x minutes (maybe an hour) uninterrupted.

Presumably like TV and put out more adverts when more viewers then
ensure the average complies with regulations by having few adverts when
not many viewers.
Unsurprisingly not being done for the benefit of the viewer or listener!

It benefits me as I usually listen in bed last thing at night :-)

Do you? I tend to use the Shipping Forecast - "......Cromaty, Forth,
Tyne, Dogger, Fisher, German Bight, etc etc... zzzzzzzzzzzzzzzzzzzzzz

[Scott]

Post by Woody

Post by Scott

Post by MB

Post by Scott
I think there are fewer adverts at off-peak times. I have heard them
say there will be x minutes (maybe an hour) uninterrupted.

Presumably like TV and put out more adverts when more viewers then
ensure the average complies with regulations by having few adverts when
not many viewers.
Unsurprisingly not being done for the benefit of the viewer or listener!

It benefits me as I usually listen in bed last thing at night :-)

Do you? I tend to use the Shipping Forecast - "......Cromaty, Forth,
Tyne, Dogger, Fisher, German Bight, etc etc... zzzzzzzzzzzzzzzzzzzzzz

I used to do that but it is too late for me now. I tried to imagine
the position of each of the sea areas as they circled (clockwise)
round the UK.

[MB]

Post by Woody
Do you? I tend to use the Shipping Forecast - "......Cromaty, Forth,
Tyne, Dogger, Fisher, German Bight, etc etc... zzzzzzzzzzzzzzzzzzzzzz

Keeping Long Wave running is a very expensive way of helping a few
people get to sleep!

[Scott]

Post by MB

Post by Woody
Do you? I tend to use the Shipping Forecast - "......Cromaty, Forth,
Tyne, Dogger, Fisher, German Bight, etc etc... zzzzzzzzzzzzzzzzzzzzzz

Keeping Long Wave running is a very expensive way of helping a few
people get to sleep!

Won't some of the shipping forecasts continue on FM? I assume this
would include the late night one.

[Woody]

Post by tony sayer
thus

Post by MB

Post by Roderick Stewart
Given that DAB is capable of bitrates up to several hundred kb/s and
normally transmitted with considerably lower ones, without knowing the
precise details I would guess it probably could. Metadata that simply
controlled gain wouldn't need as much bandwidth as the audio itself.

You need to get receivers on the market and for that you need standards
to be agreed, that takes time.
Then you need to convince manufacturers that there is a demand for it
etc etc.

Plus do serious classical listeners take Classic fm that seriously?..

Never listened to Scala then Tony?

[J. P. Gilliver]

Post by Roderick Stewart

Post by Liz Tuddenham
A long time ago, when a compressor was a large and expensive piece of
kit, it made sense to add compression (if any) before the transmitter.
Nowadays it would be a trivial matter to build a variable compressor
into every radio, so that the user could choose the degree of
compression, depending on circumstances and personal preference.

Even better to build an expander into every radio, or every radio that
hi-fi enthusiasts were willing to pay extra for. Compress the signal
before transmission to a level that doesn't sound too offensive if
nothing is subsequently done to it, so it will work with existing
simple radios that don't have the extra circuitry.

Now that does sound like a good idea. (With maybe Radio 3 - at least its
analogue FM output - remaining the one exception.)

Post by Roderick Stewart
The audio data could be accompanied by metadata to specify exactly how
the original dynamic range is to be restored.

Wasn't that one of the main aspects of NICAM - I think that's what the C
stood for! Granted, I think that was so that it could use a reduced bit
_depth_ - i. e. 14 or 12 bits, but still give the quality of 16 bit in
quieter passages - but the principle was there.

Post by Roderick Stewart
The broadcasters could start tomorrow without any disruption to users.
Nobody would need to buy any new equipment if they didn't want to.

That sounds good.

Post by Roderick Stewart
Rod.

[Scott]

Post by Max Demian

Post by Scott
Is it possible Classic has increased the volume or changed the codec
as 9 on the the bedside radio seems louder? Maybe it is because I got
the wax removed from my ears :-)

I expect they've increased the (dynamic range) compression.
I prefer Radio 3 which has none that I am aware of.

Interestingly, a friend of mine who played double bass for the RSNO
said she preferred compression where the music is there for background
(citing while ironing as an example). I know some think it is better
for in-car listening. As I recall, when DAB was developed, there was
an option to set DRC.

[Woody]

Post by Scott

Post by Max Demian

Post by Scott
Is it possible Classic has increased the volume or changed the codec
as 9 on the the bedside radio seems louder? Maybe it is because I got
the wax removed from my ears :-)

I expect they've increased the (dynamic range) compression.
I prefer Radio 3 which has none that I am aware of.

Interestingly, a friend of mine who played double bass for the RSNO
said she preferred compression where the music is there for background
(citing while ironing as an example). I know some think it is better
for in-car listening. As I recall, when DAB was developed, there was
an option to set DRC.

Back in the day there was an American compression/decompression system
for LPs - I can't for the life of me remember what it was called, but as
a system for domestic use IMO it worked quite well. However copy the
compressed audio directly from the LP onto a cassette for the car and
the compressed audio sounded superb - you could hear every single note!

[Brian Gaff]

Are you talking DBX. A linear compander which worked very well for his
removal and preserving dynamics, as its max recording level was way lower
and hence less distortion.
If you listened to it raw, though it was awful which was why they went on
using dolby on tape. The snag was that it needed to be calibrated, and was
not linear, so it made tapes of different sensitivities sound bad unless it
was set up before recording.
Brian
--
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This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
***@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!

Post by Scott

Post by Max Demian

Post by Scott
Is it possible Classic has increased the volume or changed the codec
as 9 on the the bedside radio seems louder? Maybe it is because I got
the wax removed from my ears :-)

I expect they've increased the (dynamic range) compression.
I prefer Radio 3 which has none that I am aware of.

Interestingly, a friend of mine who played double bass for the RSNO
said she preferred compression where the music is there for background
(citing while ironing as an example). I know some think it is better
for in-car listening. As I recall, when DAB was developed, there was
an option to set DRC.

Back in the day there was an American compression/decompression system for
LPs - I can't for the life of me remember what it was called, but as a
system for domestic use IMO it worked quite well. However copy the
compressed audio directly from the LP onto a cassette for the car and the
compressed audio sounded superb - you could hear every single note!

[Brian Gaff]

They have seemingly got a lower dynamic range since they went mono on
freeview. I don't know if the two events are related or just that they
decided everyone listens in cars. To me DAB is a missed opportunity to make
real hi-fi. All stations could transmit full dynamic range now, and receiver
makers could have a compression adjustment in them using software. So a car
system could make the quiet stuff louder and so on. However the same optimod
and the like seems to be used as on FM. When I first started to listen to
DAB in 2000, the in concerts that radio 2 and 3 had were wonderfully
dynamic, but compressed on fm. Now they are all compressed, in radio 2s case
almost as bad as radio 1. I recorded apop concert on FM back in the 70s on a
DBX tape, and the same concert more recently. The latter transmission was
painful to listen to due to pumping and splish splash type emphasis on the
eq.
There is no real reason why the simple act of compression could not be on
the media site its sent out through.
Brian
--
--:
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
***@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!

Post by Scott
Is it possible Classic has increased the volume or changed the codec
as 9 on the the bedside radio seems louder? Maybe it is because I got
the wax removed from my ears :-)

[Mark Carver]

Post by Brian Gaff
There is no real reason why the simple act of compression could not be on
the media site its sent out through.

With analogue transmission you have to apply compression before
transmission, you can't do so at the receiver because if the reception
is poor, you'll just wind up the noise too.

For digital it makes perfect sense to make compression a user definable
thing within the receiver

[Max Demian]

Post by Mark Carver

Post by Brian Gaff
There is no real reason why the simple act of compression could not be on
the  media site its sent out through.

With analogue transmission you have to apply compression before
transmission, you can't do so at the receiver because if the reception
is poor, you'll just wind up the noise too.

It's done in cars where the background noise should mask the hiss; in
any case, on FM you only get significant hiss on stereo, and car radios
mostly have a "blended" stereo decoding which progressively reduces the
stereo effect as reception gets poorer, so the hiss level remains low.

To apply compression before transmission would require a new radio
standard to specify it, and for bog standard radios to have expanders,
unless it's assumed that most people will want everything to be compressed.

[John Williamson]

Post by Max Demian
To apply compression before transmission would require a new radio
standard to specify it, and for bog standard radios to have expanders,
unless it's assumed that most people will want everything to be compressed.

That is, indeed, the assumption that Classic FM make. There definitely
seems to be an Optimod or software equivalent somewhere in their signal
chain.

[Scott]

On Tue, 6 Jun 2023 18:20:08 +0100, John Williamson

Post by John Williamson

Post by Max Demian
To apply compression before transmission would require a new radio
standard to specify it, and for bog standard radios to have expanders,
unless it's assumed that most people will want everything to be compressed.

That is, indeed, the assumption that Classic FM make. There definitely
seems to be an Optimod or software equivalent somewhere in their signal
chain.

Does Classic FM vary the compression through the day (according to
predicted listening environment, eg cars during commute)? I believe
the BBC used to do this.

[John Williamson]

Post by Scott
Does Classic FM vary the compression through the day (according to
predicted listening environment, eg cars during commute)? I believe
the BBC used to do this.

I've not listened enough to tell and apparently they run different
ratios on FM and DAB. Radio 3 is not noticeable compressed, though.

[Woody]

Post by John Williamson

Post by Scott
Does Classic FM vary the compression through the day (according to
predicted listening environment, eg cars during commute)?  I believe
the BBC used to do this.

I've not listened enough to tell and apparently they run different
ratios on FM and DAB. Radio 3 is not noticeable compressed, though.

AIUI BBC R3 runs through Optimod during the rush hours - something like
07h-09h and 17h-19h but at all other times send it plain at 192kb. IMSMC
they do however drop the data rate when one of the occasional stations
such as 5LSX/TMS or 4LW is on air or at least they used to. Marky will
be along shortly to put me right no doubt!

[Mark Carver]

Post by Woody

Post by John Williamson

Post by Scott
Does Classic FM vary the compression through the day (according to
predicted listening environment, eg cars during commute)?  I believe
the BBC used to do this.

I've not listened enough to tell and apparently they run different
ratios on FM and DAB. Radio 3 is not noticeable compressed, though.

AIUI BBC R3 runs through Optimod during the rush hours - something
like 07h-09h and 17h-19h but at all other times send it plain at
192kb. IMSMC they do however drop the data rate when one of the
occasional stations such as 5LSX/TMS or 4LW is on air or at least they
used to. Marky will be along shortly to put me right no doubt!

Wohnort is our friend

http://www.wohnort.org/dab/uknat.html#BBC

[John Williamson]

Post by Mark Carver

Post by Woody

Post by John Williamson

Post by Scott
Does Classic FM vary the compression through the day (according to
predicted listening environment, eg cars during commute)? I believe
the BBC used to do this.

I've not listened enough to tell and apparently they run different
ratios on FM and DAB. Radio 3 is not noticeable compressed, though.

AIUI BBC R3 runs through Optimod during the rush hours - something
like 07h-09h and 17h-19h but at all other times send it plain at
192kb. IMSMC they do however drop the data rate when one of the
occasional stations such as 5LSX/TMS or 4LW is on air or at least they
used to. Marky will be along shortly to put me right no doubt!

Wohnort is our friend
http://www.wohnort.org/dab/uknat.html#BBC

That shows that the bitrate varies, which alters the perceived quality,
but says nothing about analogue level compression.

The bit rate is now reduced to make room for special events such as
sports on other channels.

Optimod makes the quiet bits louder (Simplified explanation), which has
no effect on the DAB bitrate.

I have just read a report that all BBC radio channels use either am
Optimod or the earlier Omnia compressor at settings which vary to match
the channel profile.

[Scott]

On Tue, 6 Jun 2023 20:14:51 +0100, John Williamson

Post by John Williamson

Post by Mark Carver

Post by Woody

Post by John Williamson

Post by Scott
Does Classic FM vary the compression through the day (according to
predicted listening environment, eg cars during commute)? I believe
the BBC used to do this.

I've not listened enough to tell and apparently they run different
ratios on FM and DAB. Radio 3 is not noticeable compressed, though.

AIUI BBC R3 runs through Optimod during the rush hours - something
like 07h-09h and 17h-19h but at all other times send it plain at
192kb. IMSMC they do however drop the data rate when one of the
occasional stations such as 5LSX/TMS or 4LW is on air or at least they
used to. Marky will be along shortly to put me right no doubt!

Wohnort is our friend
http://www.wohnort.org/dab/uknat.html#BBC

That shows that the bitrate varies, which alters the perceived quality,
but says nothing about analogue level compression.
The bit rate is now reduced to make room for special events such as
sports on other channels.
Optimod makes the quiet bits louder (Simplified explanation), which has
no effect on the DAB bitrate.
I have just read a report that all BBC radio channels use either am
Optimod or the earlier Omnia compressor at settings which vary to match
the channel profile.

I suspect 'Marky' is aware of this :-)

[Scott]

On Tue, 6 Jun 2023 19:35:40 +0100, Mark Carver

Post by Mark Carver

Post by Woody

Post by John Williamson

Post by Scott
Does Classic FM vary the compression through the day (according to
predicted listening environment, eg cars during commute)?  I believe
the BBC used to do this.

I've not listened enough to tell and apparently they run different
ratios on FM and DAB. Radio 3 is not noticeable compressed, though.

AIUI BBC R3 runs through Optimod during the rush hours - something
like 07h-09h and 17h-19h but at all other times send it plain at
192kb. IMSMC they do however drop the data rate when one of the
occasional stations such as 5LSX/TMS or 4LW is on air or at least they
used to. Marky will be along shortly to put me right no doubt!

Wohnort is our friend
http://www.wohnort.org/dab/uknat.html#BBC

Returning to topic, I'm wondering if Classic FM on the Global Player
(HD audio) is compressed. My impression is that it is not.

In fact, is compression used for streaming services at all?

[MB]

Post by John Williamson
That is, indeed, the assumption that Classic FM make. There definitely
seems to be an Optimod or software equivalent somewhere in their signal
chain.

I think most (if not everyone) with have something in the chain even if
just acting as a limiter because of the penalties for overdeviating.