Quote:
Originally Posted by Ian - G4JQT
In fact it's MUCH worse that, as whoever now runs the BBC MF sites has not only abandoned the audio phase-matching, but it arrives at different tx sites now by various digital routes with differences measured in (I'd guess) milliseconds.
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It's not just the IP codecs that are taking over for a lot of inexpensive studio-transmitter links! Don't forget the latency introduced by digital audio processors like Omnia, Wheatstone and Orban.
It's gotten to the point where, if you're doing a straight music show, with no phone calls going on-air (thereby no need for a profanity delay), you can't monitor yourself using the air feed into your headphones.
What's the work-around?
What news/talk/sport stations have been doing for decades....a "dummy" chain -- ideally made to sound similar to the processed audio going out over the air, but coming straight of the mixing desk - and using analog processors to eliminate latency.
In addition ot my regular job, I do some part-time engineering work for two co-owned MW stations in my town. They use Barix Exstreamer/Instreamer IP codecs for their studio-transmitter links. These things basically stream the studio audio over the Internet to whatever location the corresponding receiver box is connected.
Latency is on the order of almost a second from where the audio leaves the studio, to where I hear it on a radio.