Oh right, I understand! For the BBC, is the headline bed restarted for each headline, or is a thunderclap ovelaid onto the bed?
Restarted.
One thing I've wondered about since the 2008 revamp is whether the vamp is restarted automatically when the transition kicks in. It seems to restart perfectly on time with the transition, and sometimes the vamp starts unexpectedly when a transition is used. For example it happened yesterday during the BOTH headlines; the last transition was welcomed with the TOTH vamp.
The Spot On can be driven from a GPO (*) (sometimes called a GPI) generated by the mixer - which can be assigned to a particular ME bank. When a transition is made on the bank, the GPO fires, and Spot On performs a specific action (i.e. starting a bed with a crash at the top)
The BBC have used GPOs to drive Spot On since the One / Six / Ten introduced variable length headlines, quite a bit before 2008, though the News Channel didn't get them until later ISTR.
Prior to the arrival of Spot On BBC News used MiniDisc players (with hotstart panels) to play audio beds / stabs etc. (And in the era of the 'Sydney Opera House' titles, the audio - as well as slaved key+fill came from a Stingray, which also generated GPOs and could be used to generate wipe transitions that triggered mixer transitions 'underneath'. Liquid News used one for their headline wipe)
(*) GPO = General Purpose Output. GPI = General Purpose Input. Most kit has both - the GPI allows a device to be controlled by an external input (usually a GPO from something else), the GPO allows a device to control something external (usually by feeding a GPI on an other device)