SIGNALS

In case you haven't noticed, a beach volleyball tournament is going on, apparently in some large city with a beach. This tournament, which includes miscellaneous other non-beach volleyball events, is on TV. Also, in case you haven't noticed, the quality of the TV audio feed is, um, variable.

A television broadcast mainly consists of two parts: the video part, and the audio part. It is a truism that in general the video part is uniformly good. The audio part, however, is not so uniform. Why is that? Well, I have a theory.

With all due respect to videophiles, the question of picture quality is relatively straightforward. As long as the camera is pointed at the subject in question, and moves with the subject, the various automatic signal compensation circuits do a pretty good job of delivering good quality video. Importantly, aside from the pointing requirement, there is relatively little human interference.

In contrast, the audio part is dependent on human interpretation. In a sporting event, you have one or more announcers; they are miked and as long as they maintain some decent mouth-to-mike distance, their sound quality should be okay. You also have various microphones around the venue to capture the excitement of the crowd. You might also have a direct feed from a venue PA system, for example, playing music. And this is where it gets tricky. A person must subjectively mix all those audio inputs.

Video might have automatic color balance, but audio has someone, somewhere, probably wearing headphones, using a combination of skill, judgment and luck to balance the audio inputs into something coherent. And sometimes it works well, and sometimes it doesn't. The camera easily points to what's happening, but the audio mix can be a crap shoot. Can you distinctly hear the announcer's every word, or does the crowd noise drown out the words? Intelligibility can be tricky. You want to understand what the announcer is saying, but you also need crowd noise. Imagine how unengaging it would be to hear only the announcer, with no crowd noise.

But you know what? That human component in the audio signal chain is what makes it so interesting. When the action reaches fever pitch, and the announcer is shouting, but the crowd is roaring so loudly that it drowns out the announcer - that's just terrific. A color balance circuit can't do that, but a human mixer can. And for all those breaking-the-rules moments that are terrific, there are also those times when breaking-the-rules audio sounds lousy. The human variable.

We now return you to your regularly-scheduled beach volleyball.