Music in my head and elsewhere

I mentioned in a previous post that I usually have a piece of music or a single phrase that runs through my mind for most of the day. This can be as simple as one line from a song or as complex as a movement from a symphony.

I start with this because since the evening news, the "theme" from my local station's news broadcast has been running, repeating. It is a fairly simple phrase, quite dramatic (as if to show impending import) but short, five notes with a telegraphic sounding coda. That started me wondering: Who composes these themes?

Think about it. Almost all television stations that broadcast news have a theme to introduce the news. Most of them are quite catchy, certainly au courrant. But where do they come from? Is there a workshop of composers who specialize in writing these themes? Is it a single person banging out tunes on a tinny upright piano, a la tin pan alley? Do the stations hire advertising agencies to find the tunes? Perhaps there is an underground network, known only to TV producers that locates the composer.

I think this is a silly, banal contemplation. But it has grabbed me for tonight. If anyone out there knows, please post a comment.