BT 21CN activation 30/4/08
DAB sounds worse than FM
Should I expect the earth to move?
--
Steve - www.digitalradiotech.co.uk - Digital Radio News & Info
The adoption of DAB was the most incompetent technical
decision ever made in the history of UK broadcasting:
http://www.digitalradiotech.co.uk/dab/incompetent_adoption_of_dab.htm
Howard Neil
> The exchange I'm on has got a WBC 21CN activation date of next Wednesday.
>
> Should I expect the earth to move?
>
>
If you believe that analogue sounds better than digital, you may find
that the sound quality of your phone is not to your liking. ;-)
--
Howard Neil
dennis@home
"Howard Neil" <hn...@REMOVETOREPLY.co.uk> wrote in message
news:_KidnbkGSdTbL43VnZ2dnUVZ8vudnZ2d@plusnet...
Its already digital and has been for years.
(8k 8 bit samples per second)
Howard Neil
Not on the local loop.
--
Howard Neil
PeterT
What changes are going to be made to the local loop post 21CN
changeover?
--
Cheers
Peter
WCZ
Nothing unfortunately. It's copper all the way to your house.
--
WCZ
PeterT
wrote:
Yes, the question was rhetorical - I'm interested to see what changes
Howard Neil expects to be made to it to make it a "digital" local
loop!!-)
--
Cheers
Peter
PeterW
Hasn't the whole network been using G.711a (64k) on all calls since
System-X came in. The conversion is in the line card for your loop (or at
you local site if you have ISDN2e (or indeed VoIP).
Why should the local loop sound different unless they are compressing with
a low MoS algorithm?
Regards
Peter
Howard Neil
It was an attempt at humour, given the OP's sig.
--
Howard Neil
R. Mark Clayton
Yes if you had Highway and an ISDN phone - much better than analog!
One could even double up to improve quality (radio stations use to do this),
although I never bothered.
IIRC the last BT analog switch was retired in the early ninties.
>
> --
> Howard Neil
DAB sounds worse than FM
> DAB sounds worse than FM wrote:
>> The exchange I'm on has got a WBC 21CN activation date of next
>> Wednesday. Should I expect the earth to move?
>>
>>
>
> If you believe that analogue sounds better than digital,
What do you mean by "believe that"? Are you suggesting that I'm wrong?
> you may find
> that the sound quality of your phone is not to your liking. ;-)
It's already digitally compressed - I've got nothing against digital audio
in general, it's just the shit sound quality on DAB I have a problem with.
Howard Neil
> Howard Neil wrote:
>> DAB sounds worse than FM wrote:
>>> The exchange I'm on has got a WBC 21CN activation date of next
>>> Wednesday. Should I expect the earth to move?
>>>
>>>
>> If you believe that analogue sounds better than digital,
>
>
> What do you mean by "believe that"? Are you suggesting that I'm wrong?
Yes, depending on local geographical features. I have both DAB and FM
and, for me, DAB is far superior. This is because of multi path signals
which cause problems on FM. DAB, however, has circuitry that combines
these multi path signals and presents one solid quality signal.
--
Howard Neil
DAB sounds worse than FM
> DAB sounds worse than FM wrote:
>> Howard Neil wrote:
>>> DAB sounds worse than FM wrote:
>>>> The exchange I'm on has got a WBC 21CN activation date of next
>>>> Wednesday. Should I expect the earth to move?
>>>>
>>>>
>>> If you believe that analogue sounds better than digital,
>>
>>
>> What do you mean by "believe that"? Are you suggesting that I'm
>> wrong?
>
> Yes, depending on local geographical features. I have both DAB and FM
> and, for me, DAB is far superior.
You're referring to reception quality issues, whereas the audio quality on
DAB even when you have rock solid reception quality is crap due to the low
bit rates the broadcasters are using.
And what would you say to someone who has poor DAB reception and they suffer
from the 'bubbling mud' sound that accompanies low signal strength DAB? Is
DAB far superior for them? No, obviously not. And remember that FM has 99%
population coverage whereas the BBC natinoal DAB multiplex only has 86%, and
10% of the population are never going to get DAB coverage from the BBC, so
I'd like to hear you justify to these people that DAB sounds better.
The only fair way to compare the audio quality of DAB vs FM is to compare
them when you've got good reception quality on both systems, which I have,
and I'm afraid FM pisses all over DAB in terms of audio quality.
> This is because of multi path
> signals which cause problems on FM. DAB, however, has circuitry that
> combines these multi path signals and presents one solid quality
> signal.
Wrong. DAB doesn't use any circuitry to "combine these multipath signals"
whatsoever. I suggest you read this:
http://www.digitalradiotech.co.uk/cofdm.htm
DAB uses OFDM, and in DAB's case this consists of 1,536 sub-carriers that
are transmitted in parallel, and each of these sub-carriers is subject to
flat (Rayleigh) fading, and there isn't any circuitry or processing that
attempts to avoid this flat fading, because it is an inherent consequence of
using OFDM. The only reason DAB works (because there are always some
subcarriers that are in a deep fade) is basically that OFDM is combined with
error correction coding so that the data on the subcarriers that are in a
deep fade (so there's a relatively high probability that the data
transmitted on those subcarriers is received in error) can be corrected. DAB
also uses time and frequency interleaving to spread out concentrated error
bursts to help the error correction decoding do its stuff.
Howard Neil
All I can say is that you ought to hear the difference where I am. FM is
unusable; DAB is excellent. It doesn't matter what theories you like to
throw at it, the simple truth is that *where I live* DAB sounds better
than FM.
--
Howard Neil
Malcolm Knight
> DAB sounds worse than FM wrote:
>> You're referring to reception quality issues, whereas the audio
>> quality on DAB even when you have rock solid reception quality is
>> crap due to the low bit rates the broadcasters are using.
<snip>
> All I can say is that you ought to hear the difference where I am. FM
> is unusable; DAB is excellent. It doesn't matter what theories you
> like to throw at it, the simple truth is that *where I live* DAB
> sounds better than FM.
You didn't understand a word of what was said did you. :-(
--
Malcolm
George Weston
"Howard Neil" <hn...@REMOVETOREPLY.co.uk> wrote in message
news:oLWdnQSbjMolfozVnZ2dnUVZ8sjinZ2d@plusnet...
Stable and un-interfered-with maybe.
The audio frequency range is, however, inferior, by all reports.
Try listening to music on DAB that has deep bass notes and high trebles and
then do a comparison with the FM sound (if of course you can get FM, which
apparently you can't!).
George
DAB sounds worse than FM
<snip>
> All I can say is that you ought to hear the difference where I am.
I'm perfectly aware of what poor FM reception sounds like - you hear it
every time you tune across the dial from station to station - everyone knows
what hiss sounds like.
> FM
> is unusable; DAB is excellent.
But you're ignoring what I said in my last post. 10% of the population is
never going to receive DAB, so DAB is pretty unusable for them, wouldn't you
agree?
As I've already said, the only fair way to compare the audio quality of the
two systems is to compare when you've got good reception quality on both
systems, or else reception quality issues distort the results, and there are
more people that can't receive DAB than can't receive FM anyway.
> It doesn't matter what theories you
> like to throw at it,
This has nothing to do with theories, it's simply about a fair way to
compare the audio quality of two systems, but you seem to want special
dispensations for DAB - i.e. you want to take into account FM reception
problems you have, but you're not prepared to take into consideration DAB
reception problems for other people, even though 6 million people in the UK
are never going to be able to receive DAB EVER! You have to divorce
reception quality from the underlying audio quality that's broadcast - it's
the only fair way to make a comparison.
Similarly, you couldn't say "an FM portable radio sounds better than a £800
DAB hi-fi tuner". You've got to remove other factors to make a level playing
field.
> the simple truth is that *where I live* DAB
> sounds better than FM.
DAB with good reception quality sounds far worse than FM with good reception
quality. Unfortunately, that name wouldn't all fit into the From column on
newsreaders, so I use the name I do.
Howard Neil
> This has nothing to do with theories, it's simply about a fair way to
> compare the audio quality of two systems, but you seem to want special
> dispensations for DAB - i.e. you want to take into account FM reception
> problems you have, but you're not prepared to take into consideration DAB
> reception problems for other people, even though 6 million people in the UK
> are never going to be able to receive DAB EVER! You have to divorce
> reception quality from the underlying audio quality that's broadcast - it's
> the only fair way to make a comparison.
I simply made the point about multipath combining which you dismiss as
it "doesn't exist". There are other people who think that it does:
http://www.mmsa.org.uk/guides/car_audio/dab_digital_radio.html
http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/6675/17896/00831772.pdf?arnumber=831772
http://www.patentstorm.us/patents/5970085-description.html
http://www.homevisionuk.com/dabexplained.htm
(just a selection from many possibles)
> DAB with good reception quality sounds far worse than FM with good reception
> quality. Unfortunately, that name wouldn't all fit into the From column on
> newsreaders, so I use the name I do.
>
>
I am happier with that explanation. It just is not true that DAB
*always* sounds worse than FM
--
Howard Neil
Malcolm Knight
news:cPlQj.70398$kN5....@newsfe1-gui.ntli.net...
> Similarly, you couldn't say "an FM portable radio sounds better than a
> £800 DAB hi-fi tuner".
I might. :-)
> You've got to remove other factors to make a
> level playing field.
As the owner of an £800 tuner (purchased late 1999), a pair of speakers
costing a great deal more than that and a 20 year old twenty quid Sony
FM portable I know which I prefer to listen to. OK, I know there are
other factors such as convenience and the cost of running a couple of
hundred watts of amplification but one annoys my ears far more than the
other. So it's quite a long time since the DAB system has been powered
up.
--
Malcolm
Howard Neil
> Stable and un-interfered-with maybe.
> The audio frequency range is, however, inferior, by all reports.
> Try listening to music on DAB that has deep bass notes and high trebles and
> then do a comparison with the FM sound (if of course you can get FM, which
> apparently you can't!).
I can get FM, just. It simply does not sound as good as DAB, mainly due
to the interference from multipath signals. All I want to do is to
listen to the radio without interference. It just does not matter what
the theory is; the listening environment usually makes such measurements
unrealistic. I do not sit in an anechoic chamber listening to music; I
listen in the real world where very deep and very high notes are
cancelled out by background noise.
Howard Neil
DAB sounds worse than FM
Actually, it's not the audio frequency range that's the problem - DAB
potentially has a higher audio bandwidth than FM due to FM using a pilot
tone at 19 kHz so they have to lowpass filter the audio prior to 19 kHz gto
allow for the filter roll off. But on both systems the broadcasters use
brick wall lowpass filters with a cutoff frequency of around 15 kHz.
The problem with the high frequencies on DAB is due to the broadcasters
using bit rate levels that are too low for the MP2 audio codec that's used
on DAB - 98% of stereo stations on DAB use a bit rate of 128 kbps, whereas
the BBC uses 256 kbps MP2 for the audio on its TV channels.
The upshot of using insufficient bit rate levels regarding the high
frequencies is that the audio samples at high frequencies are encoded with
as few as 1 or 2 bits per sample, if they're encoded at all, and with such
low resolution encoding you get a kind of splashy or metallic sound on the
treble. DAB also tens to sound dull and muffled, again due to the bit rates
being too low. Neither of these problems affect FM, because if you've got
good FM reception the limiting factor is the use of NICAM (the BBC's
national stations are distributed to the transmitters using NICAM), but
NICAM is actually very good, and you don't get any of the perceptual audio
coding artefacts you do on DAB.
It's a bit dry, but I've written a page comparing NICAM with MP2 here in
terms of quantisation noise:
http://www.digitalradiotech.co.uk/nicam_vs_mp2.htm
Quantisation noise is the difference value between the CD original and the
encoded version, and it's quantisation noise that causes all audio artefacts
you hear on compressed audio. I used 192 kbps MP2 on that, which is the
highest bit rate used on DAB in the UK, and it's only used by 1 station, so
the graphs actually significantly underestimate the amount of noise that's
added to most DAB stations' audio. But as NICAM has far lower noise levels
it's bound to provide higher audio quality - assuming good FM reception
quality..
DAB sounds worse than FM
That's what I thought...
DAB sounds worse than FM
> DAB sounds worse than FM wrote:
>
>> This has nothing to do with theories, it's simply about a fair way to
>> compare the audio quality of two systems, but you seem to want
>> special dispensations for DAB - i.e. you want to take into account
>> FM reception problems you have, but you're not prepared to take into
>> consideration DAB reception problems for other people, even though 6
>> million people in the UK are never going to be able to receive DAB
>> EVER! You have to divorce reception quality from the underlying
>> audio quality that's broadcast - it's the only fair way to make a
>> comparison.
>
> I simply made the point about multipath combining which you dismiss as
> it "doesn't exist".
I didn't say it "doesn't exist" at all. You seem to be making things up.
>> DAB with good reception quality sounds far worse than FM with good
>> reception quality. Unfortunately, that name wouldn't all fit into
>> the From column on newsreaders, so I use the name I do.
>>
>>
>
> I am happier with that explanation. It just is not true that DAB
> *always* sounds worse than FM
As I say, that name wouldn't fit into the From column, so it's staying as it
is.
DAB sounds worse than FM
> "DAB sounds worse than FM" <dab.is@dead> wrote in message
> news:cPlQj.70398$kN5....@newsfe1-gui.ntli.net...
>
>> Similarly, you couldn't say "an FM portable radio sounds better than
>> a £800 DAB hi-fi tuner".
>
> I might. :-)
True. :-)
>> You've got to remove other factors to make a
>> level playing field.
>
> As the owner of an £800 tuner (purchased late 1999), a pair of
> speakers costing a great deal more than that and a 20 year old twenty
> quid Sony FM portable I know which I prefer to listen to. OK, I know
> there are other factors such as convenience and the cost of running a
> couple of hundred watts of amplification but one annoys my ears far
> more than the other. So it's quite a long time since the DAB system
> has been powered up.
Yep, my DAB/FM tuner doesn't get used at all on DAB either.
DAB sounds worse than FM
> George Weston wrote:
>
>> Stable and un-interfered-with maybe.
>> The audio frequency range is, however, inferior, by all reports.
>> Try listening to music on DAB that has deep bass notes and high
>> trebles and then do a comparison with the FM sound (if of course you
>> can get FM, which apparently you can't!).
>
> I can get FM, just. It simply does not sound as good as DAB, mainly
> due to the interference from multipath signals. All I want to do is to
> listen to the radio without interference. It just does not matter what
> the theory is;
It's not theory, it's about making fair comparisons.
> the listening environment usually makes such
> measurements unrealistic. I do not sit in an anechoic chamber
> listening to music; I listen in the real world where very deep and
> very high notes are cancelled out by background noise.
What utter crap. First you come out with a load of crap about DAB using
circuitry to "combine multipaths" to give a solid quality signal, or
whatever it was you said, and now this.
I'd suggest you turn the volume up if the background noise is so loud...
Howard Neil
> I didn't say it "doesn't exist" at all. You seem to be making things up.
In that case I must have misunderstood you and I apologise.
--
Howard Neil
PeterC
More a case of FM sounds worse than DAB. Comparing a poor signal to a good
one isn't a valid arguement; however, the important thing is the result.
When I had a 512k connection, internet radio wasn't good but if I recorded
it and played it back it was OK, so obviously the connection. Soon as I
could get 1M+ the radio was OK.
--
Peter.
You don't understand Newton's Third Law of Motion?
It's not rocket science, you know.
PeterC
Indeed, the result is the only important parameter. I could use Hi-Def
audio, but on 2.0 speakers with the PC on...!
Howard Neil
At last, some common sense amongst all the theories.
--
Howard Neil
DAB sounds worse than FM
Apology accepted.
DAB sounds worse than FM
No, that's supporting my point, because you cannot make audio quality
comparisons on shit quality equipment, which is the same point as what I'm
making about that you can't make audio quality comparisons if you've got
reception quality issues interfering with the audio quality comparison.
DAB sounds worse than FM
So you would have written something off as sounding terrible even though
every other person might have described it as sounding excellent? That's
about as unscientific an experiment as you could ever hope to concoct.
PeterC
> PeterC wrote:
>> On Fri, 25 Apr 2008 15:39:51 +0100, Howard Neil wrote:
>>
>>> George Weston wrote:
>>>
>>>> Stable and un-interfered-with maybe.
>>>> The audio frequency range is, however, inferior, by all reports.
>>>> Try listening to music on DAB that has deep bass notes and high
>>>> trebles and then do a comparison with the FM sound (if of course
>>>> you can get FM, which apparently you can't!).
>>>
>>> I can get FM, just. It simply does not sound as good as DAB, mainly
>>> due to the interference from multipath signals. All I want to do is
>>> to listen to the radio without interference. It just does not matter
>>> what the theory is; the listening environment usually makes such
>>> measurements unrealistic. I do not sit in an anechoic chamber
>>> listening to music; I listen in the real world where very deep and
>>> very high notes are cancelled out by background noise.
>>>
>>> Howard Neil
>>
>> Indeed, the result is the only important parameter. I could use Hi-Def
>> audio, but on 2.0 speakers with the PC on...!
>
> No, that's supporting my point, because you cannot make audio quality
> comparisons on shit quality equipment, which is the same point as what I'm
> making about that you can't make audio quality comparisons if you've got
> reception quality issues interfering with the audio quality comparison.
Agreed. If I had good equipment, the room would colour the sound - then the
noise from the passing traffic (including the world's first intercity
railway 100m away)...!
dennis@home
"Howard Neil" <hn...@REMOVETOREPLY.co.uk> wrote in message
news:pfWdnSOOc989jYzVnZ2dnUVZ8umdnZ2d@plusnet...
> dennis@home wrote:
>>
>>
>> "Howard Neil" <hn...@REMOVETOREPLY.co.uk> wrote in message
>> news:_KidnbkGSdTbL43VnZ2dnUVZ8vudnZ2d@plusnet...
>>> DAB sounds worse than FM wrote:
>>>> The exchange I'm on has got a WBC 21CN activation date of next
>>>> Wednesday.
>>>>
>>>> Should I expect the earth to move?
>>>>
>>>>
>>>
>>> If you believe that analogue sounds better than digital, you may find
>>> that the sound quality of your phone is not to your liking. ;-)
>>
>> Its already digital and has been for years.
>> (8k 8 bit samples per second)
>
> Not on the local loop.
It was for me, I had ISDN.
However it is analogue in the 21cn local loop as it is now.
xCx
> The exchange I'm on has got a WBC 21CN activation date of next Wednesday.
>
> Should I expect the earth to move?
>
>
No but the wardrobe door might come open.
PeterW
> PeterW wrote:
>> Howard Neil <hn...@REMOVETOREPLY.co.uk> wrote in
>> news:_KidnbkGSdTbL43VnZ2dnUVZ8vudnZ2d@plusnet:
>>
>>> DAB sounds worse than FM wrote:
>>>> The exchange I'm on has got a WBC 21CN activation date of next
>>>> Wednesday.
>>>>
>>>> Should I expect the earth to move?
>>>>
>>>>
>>> If you believe that analogue sounds better than digital, you may
>>> find that the sound quality of your phone is not to your liking. ;-)
>>>
>>>
>>>
>>
>> Hasn't the whole network been using G.711a (64k) on all calls since
>> System-X came in. The conversion is in the line card for your loop
>> (or at you local site if you have ISDN2e (or indeed VoIP).
>>
>> Why should the local loop sound different unless they are compressing
>> with a low MoS algorithm?
>
> It was an attempt at humour, given the OP's sig.
>
DAB has nothing to do with 21CN and the poster "DAB sounds worse than FM"
who has had his feet glued to that soapbox for years has now entered my
killfile. Whilst I may agree with him regarding DAB audio quality, the way
he rams it down our throats is so boring after reading the same ranting for
months.
I presume we will see a new sig "Analogue loop sounds better than 21CN"
before too long ;-)
Peter
petert
<p...@removethis.whisker.adsl24.co.uk> wrote:
>I presume we will see a new sig "Analogue loop sounds better than 21CN"
>before too long ;-)
I somehow doubt it - are we going to have a digital loop?
--
Cheers
Peter
Howard Neil
Here's hoping. I understood that BT's experiment with blown fibre local
loop (somewhere in Pembrokeshire, I think) was a success. There doesn't
seem, to me, much purpose in such experiments unless they intend to go
digital at some stage.
--
Howard Neil
dennis@home
"Howard Neil" <hn...@REMOVETOREPLY.co.uk> wrote in message
news:0tWdnc25bp_cHY7VnZ2dnUVZ8t3inZ2d@plusnet...
Blown fibre is OK unless someone gets the wrong pipe.. then you get a room
full of glass fibre that you weren't expecting.
Howard Neil
ROFLMAO
--
Howard Neil
Tim Clark
Well it might not always be so bad - isn't the pipe the same as they use
for piping beer in pubs? Get the wrong pipe and....
Of course it may have changed now, but I believe in the early days of
blown fibre, beer pipe was used because it had the right characteristics
and was readily available.
--
Tim Clark
PeterC
Or if the pipe is the sewer - ouch!
DAB sounds worse than FM
> Howard Neil <hn...@REMOVETOREPLY.co.uk> wrote in
> news:lICdnacNxcVFX4zVnZ2dnUVZ8s3inZ2d@plusnet:
>
>> PeterW wrote:
>>> Howard Neil <hn...@REMOVETOREPLY.co.uk> wrote in
>>> news:_KidnbkGSdTbL43VnZ2dnUVZ8vudnZ2d@plusnet:
>>>
>>>> DAB sounds worse than FM wrote:
>>>>> The exchange I'm on has got a WBC 21CN activation date of next
>>>>> Wednesday.
>>>>>
>>>>> Should I expect the earth to move?
>>>>>
>>>>>
>>>> If you believe that analogue sounds better than digital, you may
>>>> find that the sound quality of your phone is not to your liking.
>>>> ;-)
>>>>
>>>>
>>>>
>>>
>>> Hasn't the whole network been using G.711a (64k) on all calls since
>>> System-X came in. The conversion is in the line card for your loop
>>> (or at you local site if you have ISDN2e (or indeed VoIP).
>>>
>>> Why should the local loop sound different unless they are
>>> compressing with a low MoS algorithm?
>>
>> It was an attempt at humour, given the OP's sig.
>>
>
> DAB has nothing to do with 21CN and the poster "DAB sounds worse than
> FM" who has had his feet glued to that soapbox for years has now
> entered my killfile.
Sorry for taking so long to reply, but I've been sobbing uncontrollably ever
since I read your post and I've become a bit dehydrated as a result.
>Whilst I may agree with him regarding DAB audio
> quality, the way he rams it down our throats is so boring after
> reading the same ranting for months.
Ranting for months? What, on here, you mean?
Tatty-bye then.
Mike
<nospam...@btinternet.com> wrote:
>
>"Howard Neil" <hn...@REMOVETOREPLY.co.uk> wrote in message
>news:pfWdnSOOc989jYzVnZ2dnUVZ8umdnZ2d@plusnet...
>> dennis@home wrote:
>>>
>>>
>>> "Howard Neil" <hn...@REMOVETOREPLY.co.uk> wrote in message
>>> news:_KidnbkGSdTbL43VnZ2dnUVZ8vudnZ2d@plusnet...
>>>> DAB sounds worse than FM wrote:
>>>>> The exchange I'm on has got a WBC 21CN activation date of next
>>>>> Wednesday.
>>>>>
>>>>> Should I expect the earth to move?
>
>>>> If you believe that analogue sounds better than digital, you may find
>>>> that the sound quality of your phone is not to your liking. ;-)
>>>
>>> Its already digital and has been for years.
>>> (8k 8 bit samples per second)
>>
>> Not on the local loop.
>
>Yes if you had Highway and an ISDN phone - much better than analog!
But surely HH was digital local loop for everything, including audio
even if you used a POTS phone. I had an NTE replaced due to very
noisy audio connections, the "digital" side was completely unaffected.
--
Mike
>Blown fibre is OK unless someone gets the wrong pipe.. then you get a room
>full of glass fibre that you weren't expecting.
Try explaining that to a BT droid in India.
--