I'm currently exploiting the 'proms' to do some comparions between:

1) prom broadcasts on BBCTV4 DTTV

2) proms on BBC R3 DTTV

3) proms on BBC R3 FM

The snag is that I have the DTTV box with the 'TV' system in the living
room, and record that onto DVD+R via analog scart. Whereas I have the FM
tuner in another room with the audio-only 'hifi' and record that onto CD-R.

I'd like to be able to record the s/pdif output of my DTTV receiver onto
CD-R. However this means either moving the CD-R recorder (which is awkward
for other reasons) or running a long co-ax from room to room.

I have a long run of co-ax so that is probably what I'd do for
test/comparison purposes. But if I can I'd like to be able to 'split' the
s/pdif signal so I can use in both places. This means finding a box that
will provide two s/pdif output streams from one. (Presumably, a box which
will need an amplifier, so has to be powered.) I may also want to put an
isolating transformer in the room-to-room s/pdif link to avoid any risk of
ground loops.

Anyone know if a splitter of the kind I'd need is available, if so, where
from, and at what cost? :-)

Failing a splitter, I can just use a switchbox, or swap cabling. But a
splitter would be more convenient if available and not too costly....

Also: I now have a DVD rewriter on my computer (*not* a windows box, not a
mac, not even x86/IBM form!) and can see the files on a DVD+R recorded
with my Philips DVD video recorder. Anyone know:

1) Are the recorded discs CSS encoded?

2) A source for an algorithm to convert the data onto the disc into an LPCM
form I can then examine/analyse?

FWIW Preliminary listening gives me the impression that the (1) BBCTV4 DTTV
sound is better than the (2) BBC R3 DTTV sound. However when recording for
comparsions this means recording (1) 'live' sic and (2) the next
afternoon. My impression is that I find (3) preferrable to (2) except for
the clearly higher background noise, but prefer (1) except for occasional
'mini-dropouts' which I suspect are due to ignition interference. However
I'm trying to get recordings I can analyse which means I need to recover
LPCM formats. Hence either a long lead, or a way to get LPCM out of the
audio recorded onto DVD+R. I'm also experimenting with different
arrangements, etc, to see to what extent preferences are either imaginary
or nothing to do with the broadcasts as such! :-)

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

In article ,
Jim Lesurf wrote:
FWIW Preliminary listening gives me the impression that the (1) BBCTV4
DTTV sound is better than the (2) BBC R3 DTTV sound.

To the best of my knowledge, BBC4 simply takes a clean feed of the R3
music balance and adds its own presenters, etc.

--
*I'm not your type. I'm not inflatable.

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Dave Plowman (News)
wrote:
In article , Jim Lesurf
wrote:
FWIW Preliminary listening gives me the impression that the (1) BBCTV4
DTTV sound is better than the (2) BBC R3 DTTV sound.

To the best of my knowledge, BBC4 simply takes a clean feed of the R3
music balance and adds its own presenters, etc.

That may be so, and I may be imagining any 'differences'. Perhaps worth
expanding on what I wrote earlier...

I only have one DTTV RX, so in my case I'm having to compare (1) with (2)
by using the 2-4pm rebroadcasts on R3 the next day. Hence it may be that
any actual differences (if real) are due to the way the rebroadcast is
made. My impression is that the DTTV broadcast isn't optimodded, but I am
not sure of this, and even if not, it might, I suppose, be altered in some
other way.

Although I have been recording both onto DVD+R, using my Philips DVDR70, I
have (mostly) so far recorded the TV in 'M2' or 'M2x' modes (2hrs or 2.5hrs
per disc), but the R3 in 'M4' or 'M6' modes (4 or 6 hours). Been doing this
as it means I can fit both the TV version and the radio version onto the
same disc, which is very convenient for comparison and storage.

Now, according to the info I have, the DVD recorder uses the same 256k/sec
data rate for audio for *all* these modes. However perhaps this is
incorrect. Hence I am now also experimenting with recording R3 DTTV with
the M2 mode.

The R3 DTTV is on a different multiplex to BBCTV4. This means I get them
with slightly different UHF signal levels. Although the signal levels at
the receiver are 'ok' I have to use a low-noise UHF preamp, and
occasionally suffer from ignition noise interference. I do not know if the
owners of the R3 multiplex process the signal so the result differs from
that the BBC would produce. Nor am I certain that my receiver (Nokia 221T)
is doing an entirely satisfactory job of recovering the audio stream. One
of the 'unknowns' here is the lack of data on the actual practical audio
performance of DTTV receivers. In theory, they should all produce the same
output. But, in practice?...

Thus there are a number of differences and uncertainties that might mean
the two results differ - perhaps with the BBC being unaware/innocent of
this, for for reasons outwith their control.

Nor I am I confident that there *is* systematic difference. I may be
imagining it. Alternatively, it may be the result of varying reception
conditions, or some other factor.

Hence my aim is to be able to recover analysable streams which I can then
compare and check in terms of dynamics, spectra, etc, etc, to see if I can
find any indicators that will help.

FWIW my impression is that *at times* the R3 DTTV signals show a strange
sort of 'modulation noise' background whereas the BBCTV4 versions of the
same music do not. There also seems a difference in level (R3 at a lower
level) at times. But given that I can't do 'instant' comparisons, and the
effects (if any) are subtle, it is very hard to be sure at present one way
or the other. Hence the attempts to record in forms I can analyse.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

On 2005-07-23, Dave Plowman (News) wrote:
In article ,
Jim Lesurf wrote:
FWIW Preliminary listening gives me the impression that the (1) BBCTV4
DTTV sound is better than the (2) BBC R3 DTTV sound.

To the best of my knowledge, BBC4 simply takes a clean feed of the R3
music balance and adds its own presenters, etc.

From listening to Elgar's "The Dream of Gerontius" this evening
("simultaneous" on Radio3 and BBC4) my impression is that:

* The BBC4/DTTV audio level is much higher than the audio level on
Radio3/DTTV. After adjusting the levels I have the same impression
as Jim, but the comparison is too difficult to be sure (I have to
adjust manually on switching).

* I cannot distinguish the audio on Radio3/DTTV from the audio on
Radio3/DAB (except that DTTV is more fragile from impulse
interference).

Is BBC4/DTTV broadcast at 256 kbit/s in comparison to 192 kbit/s on
Radio3/DTTV and Radio3/DAB?

--
John Phillips

In article , John Phillips
wrote:


From listening to Elgar's "The Dream of Gerontius" this evening
("simultaneous" on Radio3 and BBC4) my impression is that:

* The BBC4/DTTV audio level is much higher than the audio level on
Radio3/DTTV. After adjusting the levels I have the same impression
as Jim, but the comparison is too difficult to be sure (I have to
adjust manually on switching).

I also have the impression that the R3 DTTV sound is at a lower level than
the BBCTV4 sound. However I am avoiding switching back and forth as I want
to get 'complete' recordings for both enjoyment and comparison at a later
date! Hence I am comparing the 'live' sic TV4 with the 'rebroadcast' R3.
Since the R3 rebroadcasts are on at 2-4pm I wondered if they were 'daytime
listening compressed' in a way that the 'live' broadcasts are not. The
curio would be that applying something like 'optimod' would tend to lift
the level, yet it does seem lower on R3 to TV4 to me also...

* I cannot distinguish the audio on Radio3/DTTV from the audio on
Radio3/DAB (except that DTTV is more fragile from impulse
interference).

Is BBC4/DTTV broadcast at 256 kbit/s in comparison to 192 kbit/s on
Radio3/DTTV and Radio3/DAB?

I have also been wondering if the bitrates differ. Also, since the R3 DTTV
is on a different mux, if this is 'reprocessed' in some way at a point
between the BBC and the actual transmitter(s). IIUC repeatedly
expanding-compression mpeg-like streams has a detremental effect just like
repeated conversions to-from jpeg.

FWIW I have been given the name of someone at the BBC who may be able to
answer some of the questions I have, so will investigate. If I find out
anything useful I'll report back.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

In article , Jim Lesurf jcgl@st-
and.demon.co.uk writes
I'm currently exploiting the 'proms' to do some comparions between:

1) prom broadcasts on BBCTV4 DTTV

2) proms on BBC R3 DTTV

3) proms on BBC R3 FM

Bin there dun that and R3 FM wins!. Far more open and natural and easier
on the ear.

Signal from BBC Peterbourgh, Tuner Audiolab T8000, aerial Triax 4
element.......
--
Tony Sayer

tony sayer wrote:

In article , Jim Lesurf jcgl@st-
and.demon.co.uk writes

I'm currently exploiting the 'proms' to do some comparions between:

1) prom broadcasts on BBCTV4 DTTV

2) proms on BBC R3 DTTV

3) proms on BBC R3 FM


Bin there dun that and R3 FM wins!. Far more open and natural and easier
on the ear.

Signal from BBC Peterbourgh, Tuner Audiolab T8000, aerial Triax 4
element.......

So you prefer uncompressed but limited to 16KHz NICAM distorted by an
analogue transmission to 192Kbps MP2 compressed music?

There are also the options of:
NICAM from BBC2 terrestrial analogue TV (I presume the last night is on
BBC2)
BBC4 on Sky
BBC R3 on Sky.

--
Eiron

I have no spirit to play with you; your dearth of judgment renders you
tedious.

In article , Eiron
writes
tony sayer wrote:

In article , Jim Lesurf jcgl@st-
and.demon.co.uk writes

I'm currently exploiting the 'proms' to do some comparions between:

1) prom broadcasts on BBCTV4 DTTV

2) proms on BBC R3 DTTV

3) proms on BBC R3 FM


Bin there dun that and R3 FM wins!. Far more open and natural and easier
on the ear.

Signal from BBC Peterbourgh, Tuner Audiolab T8000, aerial Triax 4
element.......

So you prefer uncompressed but limited to 16KHz NICAM distorted by an
analogue transmission to 192Kbps MP2 compressed music?

Oh!, Yes please and more of it)

I know what distortion and frequency limitations I lioke)

--
Tony Sayer

In article , tony sayer

wrote:
In article , Jim Lesurf jcgl@st-
and.demon.co.uk writes
I'm currently exploiting the 'proms' to do some comparions between:

1) prom broadcasts on BBCTV4 DTTV

2) proms on BBC R3 DTTV

3) proms on BBC R3 FM

Bin there dun that and R3 FM wins!. Far more open and natural and easier
on the ear.

My initial reactions some time ago were as the above. :-)

However having started to re-compare at length, and recording items to be
able to repeatedly compare, I am finding my reactions are less clear-cut.

In part, I have the impression that I am hearing two factors when I compare
(2) with (3).

One is that the FM seems at times to show peak compression which DTTV does
not. I've measured this with DAB versus FM, and it showed that FM on the
example I had squashed the top 6dB or so. This may add some 'warmth' as it
lifts the sustain of notes compared with the peaks. I'd like to do a
similar comparison of the measured dynamics of FM versus DTTV to see if
they show something similar to see if this *is* the case.

The other is that FM has background noise at a level which becomes clearly
audible if I try listening to the FM recordings at the same peak/max level
as DTTV recordings. Indeed, this noise seems to be at a higher level than
the 'modulation noise effect' I sometimes think I hear on DTTV R3. This
makes comparison difficult as it becomes a matter of "On one hand, this, on
the other hand, that".

Overall, I'd say the FM was more 'reliable' in terms of sound quality,
albiet with the background noise. The noise being low enough that in
general it isn't really much of a problem, or even audible. But I also have
the impression that at times the R3 DTTV sound can be really excellent.

FWIW I found the sound (and performance) of the VW London symphony truly
superb on BBCTV4, but am less happy with some of the quieter sections on
DTTV R3. Alas I didn't get an FM recording of this as the amplifier gave
problems and I abandoned the attempt to get a recording that day for
'safety' or 'panic' reasons. :-)

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

On Sat, 23 Jul 2005 10:28:01 +0100, Jim Lesurf
wrote:


I'd like to be able to record the s/pdif output of my DTTV receiver onto
CD-R. However this means either moving the CD-R recorder (which is awkward
for other reasons) or running a long co-ax from room to room.

I have a long run of co-ax so that is probably what I'd do for
test/comparison purposes. But if I can I'd like to be able to 'split' the
s/pdif signal so I can use in both places. This means finding a box that
will provide two s/pdif output streams from one. (Presumably, a box which
will need an amplifier, so has to be powered.) I may also want to put an
isolating transformer in the room-to-room s/pdif link to avoid any risk of
ground loops.

Anyone know if a splitter of the kind I'd need is available, if so, where
from, and at what cost? :-)

As SPDIF has similar electrical characteristics to video a video DA
will work. I've used a Keene KDA video & audio DA (currently £70) for
this very purpose and it works fine. I removed the HPF on the s-video
branch to give me 2 video DAs.

If your SPDIF source has a healthy output level, and your receivers
are sensitive, you might get away with a passive splitter.

Bill