Last week was a bit of a busy one for me, dashing around between Kingswood Warren (the home of BBC R&I), Sky and a trip to the BBC's facility in Glasgow (as well as having just returned from a long weekend in Devon) but I just wanted to share with you some of what I got up to last Tuesday. I spent the afternoon and evening with the sound team of Later Live with Jools Holland at Television Centre. I was there to look at their surround sound production and the technology setup they have. It was an interesting insight into the programme maker's view on all this surround stuff, and while there is considerable enthusiasm from the team, it does add to their workload...To take just one aspect, let's think about monitoring. This is the process of listening to (or watching) your own output to ensure that it's as expected. Back in the days of mono, it was easy. Stereo got a bit more tricky, but a pair of speakers or a decent set of headphones and you're well on your way. Surround makes things rather trickier.

First off, to listen to a surround sound mix, you need a surround sound system. Sounds obvious, but think not only about the equipment cost but also of the space required to construct such a system. Of course, a very large number of listeners will downmix the surround sound to a stereo output because not everyone has a surround setup, so not only must we monitor the 5.1 mix but also the stereo downmix of the 5.1 mix. That in turn is separate to the 'native' stereo mix which goes to BBC 2, where no surround is involved.

Then there's metadata. This 'data about data' controls some elements of how your surround sound receiver decodes the audio, so ensuring the correct metadata is vital, as we know only too well. Therefore the monitoring requirements also include 2 metadata components; checking the metadata we're sending out is as we intended, and checking how the audio sounds after the metadata effects are applied to the decoding. Finally, we really ought to be checking during a live programme that what makes it to your set-top box is what we're sending out, so we aim to do 'off-air' monitoring too.

This means a total of at least 4 audio mixes to listen to as well as metadata checks to be done. You'll be pleased to hear that Later does indeed do all these checks, and so we can be very confident that the audio you receive as a viewer is as the sound supervisor intended. The Later team were instrumental in getting a surround sound suite set up at Television Centre to allow monitoring and in some cases mixing to be done in a dedicated environment rather than the crowded sound gallery. But all this costs money, needs training for the staff involved and adds complications, so ensuring it's done right for all shows all the time is a challenge. Imagine doing all this on an outside broadcast, and you'll see that the challenge there is greater still. It's one we're facing head-on however, and the availability of new testing equipment is helping. In Television Centre's surround room for example they now have a very useful little box which allows us to examine the metadata they're sending out and be sure it's correct, rather than assuming that the metadata authoring equipment is doing it's job. Assumption is, after all, the monther of all mess ups...

I’m an engineer with the BBC and sharing information about my work, but this is my personal website.