Dynamics and level compression - FM vs DAB

**Jim Lesurf[_2_]** · September 10th 08, 01:49 PM posted to uk.rec.audio

I have now put up a page that compares the dynamics and level compression
on FM with that on DAB. The page can be found at

http://www.audiomisc.co.uk/HFN/DABvs...ewithlike.html

This is an updated and expanded version of a short item that was published
in HFN. The results are broadly similar to the comparisons of FM with DTTV,
but I have been able to give more details of the level compression
behaviour. I've also covered BBC R1/4 as well as R3.

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

**Don Pearce** · September 10th 08, 01:59 PM posted to uk.rec.audio

Jim Lesurf wrote:
I have now put up a page that compares the dynamics and level compression
on FM with that on DAB. The page can be found at

http://www.audiomisc.co.uk/HFN/DABvs...ewithlike.html

This is an updated and expanded version of a short item that was published
in HFN. The results are broadly similar to the comparisons of FM with DTTV,
but I have been able to give more details of the level compression
behaviour. I've also covered BBC R1/4 as well as R3.

Slainte,

Jim

Maybe there is an answer for the pop stations. I think it is a fair
assumption that the little ones now have their favoured (ie radio
playlist) tracks on their ipods as soon as they are released. So pop
stations don't actually need to broadcast them - just trigger the
playing of them from the player, along with suitably inane banalities
from a DJ, which could be broadcast.

d

**tony sayer** · September 11th 08, 09:53 AM posted to uk.rec.audio

In article , Jim Lesurf
scribeth thus
I have now put up a page that compares the dynamics and level compression
on FM with that on DAB. The page can be found at

http://www.audiomisc.co.uk/HFN/DABvs...ewithlike.html

This is an updated and expanded version of a short item that was published
in HFN. The results are broadly similar to the comparisons of FM with DTTV,
but I have been able to give more details of the level compression
behaviour. I've also covered BBC R1/4 as well as R3.

Slainte,

Jim

And from that I quote;!...

"However around the start of the Proms in 2006 i.e. after Iâ€™d written
the original article the BBC suddenly reduced the bitrate on R3 to 160
Kbps. The result was quite dire, and prompted a great deal of angry
complaints. Particularly because for most of the time the BBC were using
the â€˜stolenâ€™ bitrate to run a rolling trailer for a station that wasn't
on-air! One consequence was that the first weeks of Prom broadcasts on
DAB that year sounded awful. After initially trying to dismiss the
criticisms and pretend that the sound quality hadn't suffered, the BBC
finally relented and R3 on DAB reverted to mainly using 192 Kbps".

Good old auntie!, shows how deaf the poor old soul is getting and her
attitude to sound quality. Perhaps her ear trumpet needs blowing out?.

You'd think the old dear could use the greater bandwidth on satellite
but she is a stubborn old bitch..

Meanwhile over in Jerryland they use 192 on satellite for mere talk
stations preferring 256 or even on Bayern 4 320 K/bits

Now thats what I call digital quality

)

You ought to treat yourself to a digital satellite system Jim there're
sod all money now!. Most all have a SPDIF out for connection to an
external DAC....

--
Tony Sayer

**Jim Lesurf[_2_]** · September 11th 08, 03:23 PM posted to uk.rec.audio

In article , tony sayer

wrote:
In article , Jim Lesurf
scribeth thus
I have now put up a page that compares the dynamics and level
compression on FM with that on DAB. The page can be found at

http://www.audiomisc.co.uk/HFN/DABvs...ewithlike.html

And from that I quote;!...

"However around the start of the Proms in 2006
[snip]

I'd recommend people to read the actual article. Not to take just a quote
presented out of context. :-)

The reasons being the same ones that prompted me to write the article.
Namely that:

A) Simply considering bitrates and ignoring other factors means you fail to
take into account everything that can affect the audible results.

B) That when you *do* consider other factors - as the article does, but
Tony's quote omits - you might not come to the same conclusion as indicated
by the quote presented out of context.

C) That your conclusions might change from one radio (or TV) station to
another.

You ought to treat yourself to a digital satellite system Jim there're
sod all money now!. Most all have a SPDIF out for connection to an
external DAC....

Perhaps if you consider the entire article you will understand some of the
reasons that I have not yet bothered. :-)

Slainte,

Jim - still thorougly enjoying the proms on DTTV BBC4. :-)

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

**Tony** · September 11th 08, 04:54 PM posted to uk.rec.audio

"Jim Lesurf" wrote in message
...
I have now put up a page that compares the dynamics and level
compression on FM with that on DAB. The page can be found at

http://www.audiomisc.co.uk/HFN/DABvs...ewithlike.html

Interesting. I heard a Prom the other night on DAB, Chicago SO playing
Shostakovich 4th symphony. The dynamic range certainly seemed wider than I
am used to on R3 FM. Of course FM has to deal with pre-emphasis, so
percussion can be quite seriously affected.
--
Tony W
My e-mail address has no hyphen
- but please don't use it, reply to the group.

**tony sayer** · September 11th 08, 07:03 PM posted to uk.rec.audio

In article , Jim Lesurf
scribeth thus
In article , tony sayer

wrote:
In article , Jim Lesurf
scribeth thus
I have now put up a page that compares the dynamics and level
compression on FM with that on DAB. The page can be found at

http://www.audiomisc.co.uk/HFN/DABvs...ewithlike.html

And from that I quote;!...

"However around the start of the Proms in 2006
[snip]

I'd recommend people to read the actual article. Not to take just a quote
presented out of context. :-)

Yes understand that it was all about processing and no real reason from
Auntie as usual why its done differently on FM and not DABble and
DTV.....

The reasons being the same ones that prompted me to write the article.
Namely that:

A) Simply considering bitrates and ignoring other factors means you fail to
take into account everything that can affect the audible results.

Indeed.. Tho bitrates are very much a digital broadcast problem as is
transcoding etc..

B) That when you *do* consider other factors - as the article does, but
Tony's quote omits - you might not come to the same conclusion as indicated
by the quote presented out of context.

Its made to point out that old auntie BBC hasn't changed her "knows
best" ways over the years despite all the bull**** she dispenses..

C) That your conclusions might change from one radio (or TV) station to
another.

Indeed they might..

You ought to treat yourself to a digital satellite system Jim there're
sod all money now!. Most all have a SPDIF out for connection to an
external DAC....

Perhaps if you consider the entire article you will understand some of the
reasons that I have not yet bothered. :-)

Ummm... thats not to receive UK digital radio, but that from France and
Germany and other European countries who have higher broadcast
standards

....

Slainte,

Jim - still thorougly enjoying the proms on DTTV BBC4. :-)

Indeed.... and as popular as ever.. The few I've been to this year were
packed!...

Summer.. what there was of it is --officially-- over once the Proms have
finished

..
--
Tony Sayer

**tony sayer** · September 11th 08, 07:05 PM posted to uk.rec.audio

In article , Tony
scribeth thus
"Jim Lesurf" wrote in message
...
I have now put up a page that compares the dynamics and level
compression on FM with that on DAB. The page can be found at

http://www.audiomisc.co.uk/HFN/DABvs...ewithlike.html

Interesting. I heard a Prom the other night on DAB, Chicago SO playing
Shostakovich 4th symphony. The dynamic range certainly seemed wider than I
am used to on R3 FM. Of course FM has to deal with pre-emphasis, so
percussion can be quite seriously affected.

Mind you the Albert hall isn't- -that- quiet for some concerts;!..

The audience population is getting noisier as they age..
--
Tony Sayer

**John Phillips[_2_]** · September 11th 08, 10:02 PM posted to uk.rec.audio

On 2008-09-10, Jim Lesurf wrote:
I have now put up a page that compares the dynamics and level compression
on FM with that on DAB. The page can be found at

http://www.audiomisc.co.uk/HFN/DABvs...ewithlike.html

This is an updated and expanded version of a short item that was published
in HFN. The results are broadly similar to the comparisons of FM with DTTV,
but I have been able to give more details of the level compression
behaviour. I've also covered BBC R1/4 as well as R3.

I think you know I agree about "

Newsgroups: uk.rec.audio
From: John Phillips
Subject: Dynamics and level compression - FM vs DAB
References:
Organization:
Reply-To:
Followup-To:

On 2008-09-10, Jim Lesurf wrote:
I have now put up a page that compares the dynamics and level compression
on FM with that on DAB. The page can be found at

http://www.audiomisc.co.uk/HFN/DABvs...ewithlike.html

This is an updated and expanded version of a short item that was published
in HFN. The results are broadly similar to the comparisons of FM with DTTV,
but I have been able to give more details of the level compression
behaviour. I've also covered BBC R1/4 as well as R3.

I think you know that I agree (ref. BBC R3) with your "What was most
obvious was that DAB had an audibly wider dynamic range with less
background noise than on FM."

However I also note your "We can see that the sound level on FM during
extended quiet passages of music is being lifted by around 8-10dB compared
with DAB." This is also something I observed.

The ambience of the RAH when listening to the Proms on R3/FM is probably
a "trademark" for BBC R3/FM. It is something I had appreciated and
enjoyed over many years, as a measure of the quality and "realism" of
the broadcasts.

It hadn't really occurred to me until I first listened to R3/DAB that this
R3/FM ambience was always much more exaggerated than it was whenever I
was in the RAH in person. Comparing FM to DAB made me realize actually
that R3/DAB also doesn't get the RAH right either - it actually
under-represents the real ambience.

Nevertheless, the result of my comparison was that I changed my mind
about the warm ambience of R3/FM and began to enjoy the restored dynamic
range of R3/DAB (and now R3/DTTV and BBC4/DTTV).

Even so, I think the human brain's audio appreciation capability is
very adaptive if its pre-conceptions will let it just get on and enjoy
the music.

--
John Phillips

**Jim Lesurf[_2_]** · September 12th 08, 07:35 AM posted to uk.rec.audio

In article , Tony
wrote:
"Jim Lesurf" wrote in message
...
I have now put up a page that compares the dynamics and level
compression on FM with that on DAB. The page can be found at

http://www.audiomisc.co.uk/HFN/DABvs...ewithlike.html

Interesting. I heard a Prom the other night on DAB, Chicago SO playing
Shostakovich 4th symphony. The dynamic range certainly seemed wider
than I am used to on R3 FM.

That is my impression, also. I must admit, though, that during the last
couple of years I have largely abandoned listening to FM

Of course FM has to deal with pre-emphasis, so percussion can be quite
seriously affected.

I don't know if pre-emphasis plays much part in this, but it is an
interesting point. The data does show that any sudden loud peaks have their
level swiftly pulled down on FM R3, and that the gain in a following quiet
period is slowly ramped up.

I can see the point of the compression as it helps pull extended pp periods
above the background noise on FM. But I now prefer digital transmissions
which don't have the problem.

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

**Jim Lesurf[_2_]** · September 12th 08, 07:55 AM posted to uk.rec.audio

In article , John Phillips
wrote:
On 2008-09-10, Jim Lesurf wrote:
I have now put up a page that compares the dynamics and level
compression on FM with that on DAB. The page can be found at

http://www.audiomisc.co.uk/HFN/DABvs...ewithlike.html

[ 20,000 blank lines snipped! :-) ]

The ambience of the RAH when listening to the Proms on R3/FM is probably
a "trademark" for BBC R3/FM. It is something I had appreciated and
enjoyed over many years, as a measure of the quality and "realism" of
the broadcasts.

It hadn't really occurred to me until I first listened to R3/DAB that
this R3/FM ambience was always much more exaggerated than it was
whenever I was in the RAH in person. Comparing FM to DAB made me
realize actually that R3/DAB also doesn't get the RAH right either - it
actually under-represents the real ambience.

Alas, it is many years since I have been able to attend a Prom in person.
Distance and decrepitude deter. One reason why the broadcasts and my
recordings of them are now important to me!

These days I tend to prefer the BBC4 TV Proms to R3. I have gained two
impressions wrt ambience. One is that there often seems to be some LF
noise, perhaps due to air conditioning or passing traffic. However it may
be the audience swaying or breathing! :-)

The other is that this varies in being noticable from one Prom to another.
Indeed, I get the impression that the entire sound balance changes from one
to another. Not sure how much this is the orchestras playing differently,
though.

For example, the BPO/Rattle Prom of Brahms/Shostakovich seemed to have
richer (louder) bass strings than some other proms.

For perhaps obvious reasons such ambient noise seems louder when there is
something like an extended violin solo. But I am not sure how much this is
mic useage, change in overall recording/broadcast gain, or my hearing
adapting, or my winding up the volume at home!

Nevertheless, the result of my comparison was that I changed my mind
about the warm ambience of R3/FM and began to enjoy the restored dynamic
range of R3/DAB (and now R3/DTTV and BBC4/DTTV).

Even so, I think the human brain's audio appreciation capability is very
adaptive if its pre-conceptions will let it just get on and enjoy the
music.

Yes. If digital broadcasting hadn't appeared I'd probably still be happy
enough with FM apart from the background noise level and the way ignition
interference can pop up at the most annoying/distracting moments. But these
limitations where what drove me to try digital in the first place.

One thing I didn't mention on the pages was that I have also been struck my
how my older recordings from R3 (back from circa 1980) seem to have a wider
dynamic range despite my having to alter the recording gain at times
because of the limited SNR of domestic cassette and rtr tape. I presume
this ties in with what Trevor Butler reported and that the BBC simply
didn't apply automated level compression in past days as they do now.

I do sometimes notice level adjustments on the BBC4 prom broadcasts, but
they give me the feeling they are being done by a human who is following
the score and tweaking with intelligence to make the result. Not done any
comparisons as yet, but I have the impression that when they put Proms on
BBC1/2 they use more level compression. I do have one or two examples of
the same performance on both BBC4 and BBC2 so may use them to check this
when the necessary round tuit is in stock. :-)

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html