I've been emailing Christopher off-list about this - I suspect it may well be a reciever issue. Most of the services on mux 1 are coded in London, and are the same across much of the country on DTT -- and I'm not seeing any phase issues on our monitoring here, with a couple of different set-top-boxes.
I've suggested that Christopher tries another reciever, or moves the aerial to somewhere with better signal strength. (I don't know that much about how the decoding process works, but perhaps someone more fluent in DVB will know - is it possible that error correction and recovery could be doing odd things to the sound in the event of low signal strength?) - martin On 3/6/08, Matt Barber <[EMAIL PROTECTED]> wrote: > Have you tried two different freeview receivers? Could it be something > strange going on in hardware, or delay introduced on speaker setup / > processing? > > > > On Thu, Mar 6, 2008 at 1:08 PM, Steve Jolly <[EMAIL PROTECTED]> wrote: > > > > Christopher Woods wrote: > > >> Can you give an exact channel, date and time when you > > >> observed the phenomenon? (03:59 GMT last night on N24, perhaps?) > > > > > > Definitely. Observable on BBC2 last night/this morning (05/03/2008) > during > > > the intro for "Spin" (03:44am). Also observable during the 60second > > > countdown buffer for N24 top of the hour (4am). I can send MPEG2 files > if > > > you want (direct streamrip, advantage of having USB DTV receiver). > > > > I have access to DTT stream recordings. :-) I took a look at the N24 > > music you mentioned. Listening to it, there's a very clear difference > > in the stereo characteristic of the sound between the (virtually mono) > > talking head segments on either side of the music, and a lesser > > difference between the music at the end of the special report and the > > N24 countdown in question. > > > > Converting the stereo to mid/side encoding and listening to the new > > channels separately, the side channel contains virtually no LF > > component, whereas the mid-channel contains plenty - you'd expect them > > to contain roughly the same amount if the signal had been subjected to a > > 90 degree phase offset, and you'd expect all the low frequencies to be > > concentrated in the side channel in the case of a 180 degree phase > > inversion. > > > > So at the moment, I don't see any evidence for an overall phase error, > > I'm afraid - at least for the one section of audio I've had a look at. > > :-) The difference in the characteristic of the sound that I can hear > > could simply be due to the transition between dead-centre mono speech > > and a very complex bit of music with a broad sound stage. > > > > > > > > > > S > > > > - > > Sent via the backstage.bbc.co.uk discussion group. To unsubscribe, please > visit > http://backstage.bbc.co.uk/archives/2005/01/mailing_list.html. > Unofficial list archive: > http://www.mail-archive.com/backstage@lists.bbc.co.uk/ > > > > - Sent via the backstage.bbc.co.uk discussion group. To unsubscribe, please visit http://backstage.bbc.co.uk/archives/2005/01/mailing_list.html. Unofficial list archive: http://www.mail-archive.com/backstage@lists.bbc.co.uk/
