Reply With QuoteD’oh! Just realised that radio 4 is internet streaming, not FM. 🙄
BBC Radio 4’s pips just now were sounded at a time.is indicated time of 08:00:45.
What gives, and which is right?
D’oh! Just realised that radio 4 is internet streaming, not FM. 🙄
DAB is often ''off''.Originally Posted by JGJG
"Once is happenstance. Twice is coincidence. The third time it's enemy action."
'Populism, the last refuge of a Tory scoundrel'.
Don't forget to allow for DUT1 as well.
Lot's of things are off by more than that.
Try switching on terrestrial TV on say BBC1 then powering up your sky box on the same channel. Note the programme lag as the TV flips over to Sky. So time given on TV is not accurate. Probably though only WIS care.
The analogue signal is accurate to the split second. The digital signal has a built-in time lag and is inaccurate. On R4 the analogue sound of Big Ben chiming the hour is broadcast live, with a microphone in the bell tower. Nerds who listen carefully will hear a slight change in the ambient noise as the mike goes 'live'.
How wonderful that the Nation gathers daily listening out for the comforting chimes of an ancient mechanical clock.
There's no such thing as an 'analogue signal' or 'accurate to the split second'. All methods of distribution have been digitised & it's just that some have much longer latencies than others, particularly those that have been multiplexed a number of times (eg the Sky off-sat signals).
FM is digital? Every day’s a school day...
You won't detect any delay on fm....but on dab you will. I've stood in the studio as the fader is opened, , and heard it on the monitoring radio at exactly the same moment. There's no audible delay. There certainly is on dab.
What's more, if you are listening on fm on Waterloo bridge, you will hear Big Ben from the tower, and on your radio, at the same moment. Whatever digital delay there is in transmission is not audible in practice.
The dab time signal is a bit dishonest. You won't get precision.
The transmission is analogue, but the distribution through the system is digital. It has been for a very long time. This was a source of amusement back in the day, when some would argue that their analogue FM tuner was far superior to the new-fangled digital CDs.
I once heard it said that the pips on Radio 4 Long Wave are as accurate as you can get from the BBC, as they take the simplest path.
Without knowing the technical specs of the distribution system, I can think of two possible explanations for this. Firstly that the distribution system was running at a higher encoding spec than a CD (e.g. 192kHz/24bit as many recording studio systems do, vs 44kHz/8bit for CDs), prior to being converted to FM. Secondly, that something else in the encoding/decoding path was just produced a subjectively better sound, e.g. the frequency modulation process removed some transient artefacts that are not pleasing to the ear. It would be good to know if something like this is the case, or we are just kidding ourselves.
@paskinner, thanks for the explanation. I knew the analogue broadcast pips were accurate but I’d never realised that the chimes were actually live.
Well whether you think you can detect a difference or not, it's there as there is always latency in the conversion processes. As I recall the mic run goes to Millbank & then to BH but I'm not sure if the A/D is in Millbank or later in the chain in BH. It's true that the terrestrial R4 distribution is the most direct & it's a relatively short run to the transmitters in London but even that has increasing latencies the further north you go.
Someone’s turned off Big-Ben though for maintenance. So is the BBC still doing the chimes - I haven’t listened for ages.
Last edited by MartynJC (UK); 20th February 2018 at 18:21.
Not just nation! When I lived in Sri Lanka it used to choke me hearing “good morning from a wet and windy London” followed by Big Ben on the World service, when it was 35’C and blazing sunshine!
Sent from TZ-UK app on an iPhone
I remember they were debating whether to use a recording of Big Ben’s chimes for the duration of maintenance, or mike up a different bell in a different clock. Think they went with the former.
http://www.bbc.co.uk/news/uk-politics-40922169
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