There is a certain adrenalin rush to going live, as it's when your ‘It'll be all right on the night’ assurances are put to the test, and any mishaps are immediately transmitted to the viewers. However, you, as the sound department, need not only to handle the sound output from your mixer, but also check the circuits to and from base, and ensure that you are both sending the required level and receiving the correct feeds from them.
Links vehicle
More often than not, you will be working into a separate vehicle which provides the link to your base via satellite, microwave, fibre optic, or ISDN. It's always advisable to know which methods of link are in use (some locations may require a combination) as it might affect the availability of some of the reverse circuitry, and/or cause delays in the signal path. The engineer on board will establish the link and may also handle all the identifications and deal with the correct provision of your talkback, etc.
They will expect to receive your output (probably on XLRs) and will provide you with incoming feeds, possibly on break-out boxes, or you may be handed one box connected to a cable loom into which you plug your output and select the relevant communications facilities from its various outlets.
Communications
Depending on the complexity of your OB, and the facilities available via the links vehicle, there are a number of communications facilities you may require from base.
Omni (or open) talkback
Continuous talkback straight from the control room or gallery has the purpose of controlling and co-ordinating the live broadcast. Programme sound is often heard over omni talkback from loudspeakers in the gallery.
Switched talkback
This is only operative when switched by the producer/director in the gallery. Switched talkback is usually required by the presenter on site, so that they only hear specific instructions in their earpiece. On a complex OB, with more than one presenter, you may require more than one independently switched talkback feed.
Reverse talkback
This is a switched talkback from your OB back to the gallery, for use either for engineering purposes, or for a Floor Manager. You will almost certainly need a talkback box on a flying lead for more complex operations, and you should always have the means to provide it as an emergency spare even if you have:
Obviates the need for wires strewn about a location, and allows greater flexibility for all concerned. The frequency in use must be licensed (via JFMG in the UK), and can suffer from RF problems as outlined in Section 9, Mics: cables and radio; Radio mic rules. The other problem with radio talkback is that it tends not to perform well in extremely noisy surroundings, and is liable to distortion if the volume is turned up too high. (Hence the need for the cabled standby, as mentioned above.)
Clean feed
The overall programme sound mix fed back to you minus your own output (known as mix (or mixed) minus in the USA). This obviates any of your contributors hearing themselves whilst speaking (highly off-putting, even for professionals), and overcomes echo effects from circuit delays. Do not confuse this facility with foldback, although itself a selective feed, which you do not want.
‘When are we on?’
Omni talkback is vital in conveying decisions reached in the gallery as to the timing of any live event. The less control a programme exerts on an event, the more likely changes necessitate altering the time and duration of your on-air piece. For this reason, many experienced presenters prefer to have omni talk-back in their ear piece, so they're aware of last minute decisions which, in the heat of the moment, may inadvertently not get passed on to them via switched talkback. The downside is that they may hear themselves when you do go on-air, but they accept that and have learnt to mentally ‘turn it off’.
The gallery may frequently ask what's happening at your location, and whilst you're not on-air, the answer can be passed via your main sound output. Quite often the gallery wish to converse with the presenter, and listen to his/her answers via their pre-fade. Once on-air, questions from the gallery can only safely be answered on reverse talkback, do not use mobile phones!
Circuit check
When circuits are being established, the normal signals sent to line are bars and tone. Many bars generators these days have the facility for adding a text identification, but to confirm that your signal is the one being received, it's standard practice to cut to ‘ident.’.
Cut to ident.
If you are cutting your outgoing tone, it should be done in conjunction with reverse talkback or a phone connection to base, so that you can verbally confirm the moment you cut and restore your signal. Normally you would do this two or three times, saying ‘Gone, back, gone, back …’ as you cut, until base confirm they're receiving the correct signal (you can often hear your signal cutting over the talkback/phone circuit).
Similarly, you may need to ask base to identify the various talkback and clean feed circuits to your link/OB, and this is done in a similar manner. However, for ease of identification, outgoing circuits from base often have a tape loop playing on them, for example ‘This is the clean feed circuit from Studio A to New Leaf OB’.
Be aware that if you're working on a major event, especially with several other sources feeding into base, a general election, for example, you may be asked to identify your outgoing circuit several times, and probably immediately before you go live. Don't assume because you've done it once, it won't happen again.
By the same token, with major events you need to keep an eye (ear?) on your incoming circuits, since with the ongoing havoc and chaos which frequently surrounds live broadcasts, last minute re-plugging and re-scheduling at base may inadvertently re-direct your circuits elsewhere.
On-air
In a well-ordered universe, you will have been given a clear indication of your precise on-air time, and the expected duration of your contribution. Back in the real world, assuming the omni talkback remains clear, you may be given ample warning and precise cues, or you may simply hear the strangled cry of ‘We're on you …!’.
The worst case scenario is losing some or all of your reverse circuits, and having to rely on an off-air feed to cue your contributors. Should this happen, you may find that the only indication you have that your own output is still being received at base is when you get ‘cut to air’. This is probably the only time I'd recommend having a mobile phone in use, to find out what on earth's happening! But do turn it off once you're on-air, and have established that everything is sorted.
Whilst every OB should have an off-air vision feed available, under no circumstances should you allow off-air sound to be fed to loudspeakers or a presenter's earpiece on site. Quite apart from the possibility of putting the presenter off their stride by hearing themselves, you'll almost certainly get a howl-round of mammoth proportions1, and necessitate base or the network cutting away from you forthwith. No matter how it occurred, you'll shoulder the blame!
So, even if members of your on-site production team ask for programme sound to be fed to a loudspeaker for the benefit of contributors or guests, insist that they listen via headphones or earpieces away from the action area, preferably via a distribution box (and/or use a parallel box which has one input, either jack or XLR, and several jack socket outputs for headphones) over which you have control of the volume. Having insisted of course, you may be expected to supply headphones and/or earpieces, so you should check when receiving a booking for a live broadcast whether this facility is required.
It is good working practice to carry spare headphones and earpieces, but if you do, also ensure that you have disinfectant wipes to clean them before and after use. Professional presenters have their own moulded earpieces, but you will have to provide the necessary lead and feed for them. They never carry a spare, and you will be their hero forever if you can provide them with an emergency spare when theirs fails!
Standby (hot spare)
Speaking of emergencies, always have at least one line-fed standby mic plugged, especially if you are using radio mic/s for your main sound. Depending on the event, your decision will probably be between using either a reporter's hand mic or a gun mic.
Live – from a phone near you!
There are various computer based devices available that allow you to send sound and vision via a phone (landline or mobile, although the latter is not to be recommended, as has already been mentioned, once or twice) or ISDN line in real time. At present, the quality, due to the compression rate applied to the signal, is not up to broadcast specifications. However, because of their portability, they're being utilized more and more for ENG work, especially on assignments abroad.
The more sophisticated devices allow you to work at different resolutions (variable signal compression), depending on the frequency spectrum available for your transmission, i.e. phone, ISDN, LAN or satellite. Thus, several data rates are available, and if you have sufficient bandwidth, you can send a broadcast quality signal in real time. Another option open to you is to send uncompressed full broadcast quality sound and pictures down a phone line, but not in real time. A typical data transfer rate for a phone circuit at present is in the order of forty minutes on-line required to transmit one minute's worth of sound and pictures. Whichever option you choose, the base to which this data is sent will obviously need to have the relevant software installed to interpret the signal.
1 Unless you're live to air via a satellite, which can introduce a delay of up to two seconds. It eliminates the possibility of a howl-round, but if a presenter has programme sound in their earpiece (against your advice, naturally), even though they are used to hearing themselves, the second/s delay could render them speechless!
Should you have sufficient equipment and time at your disposal, you could feed incoming comms via a second (small mono) mixer, and provide an on-site mix of talk-back. In this way, when your presenter is talking, you fade down the studio sound, and fade it back up after their reply, so that they can hear the studio.