Tips & Techniques - May 1992

You're Right, It's Left, It's Gone!

from Dave Oliwa, Production Director, KTXQ-FM, Dallas, TX

So, on this sweeper, you say to yourself, I'm going to go hog wild with the stereo. The all-expense-paid trip means I get to use that Roger Ramjet fly-by I just found deep in the cuts of the "Military" sound effects library disk I never use. That EQ'd repeat-the-last-word-I-just-said voice can go way over to the left. And that laser can bounce all over the spectrum if I've got the channels to do it.

Well hey, it sounds great! Lots-O-Stereo. Big, big, big! The only problem? It was too big, big, big. The primal urge of the Producer is to make stereo separation sound like

S-T-E-R-E-O S-E-P-A-R-A-T-I-O-N. But, there's a catch.

Let's talk technical for a moment. Stereo is, by definition, two channels creating a line of sound from speaker to speaker in the mind of the listener. "The center" is an equal amount of signal being sent to both left and right. A sound all the way left has the same amount of signal sent to it as the signal sent to left when an equal amount of signal is sent to right for positioning audio in the center. (Stick with me and I'll promise never to write a sentence like that ever again.) In plain English, a signal that is all left or all right is half the volume of sounds in the center when you look at the big picture. Yea, you may notice it more, but that's because it's coming out of one speaker. Most everything that is recorded is not all the way left or right -- it is somewhere between left and right, with the majority of signal in a very close proximity to center. The reason? The scourge of stereo. The slimer of spectrum. The NFG of THX.

Mono.

I know it's a heartbreaker, but panning all the way left or right decreases by fifty percent the volume of anything recorded that way when compared to center in mono. Think about it -- anything your station's transmitter processing sees in the center as being too loud will cause the compression to kick in and pull both left and right down, lowering the volume even further on signals that are recorded exclusively to left or right. If the box in your audio chain reacts more to one kind of waveform more than another, you could lose an individual channel's signal completely if something going on in the center trips its trigger the right way.

The solution is just a little self-control. Never pan anything all the way left or all the way right. On my board, nine o'clock on the pan pot is pretty far left, and three o'clock is pretty far right. It ain't CinemaScope, but everything will be heard when the two channels are combined into mono.

What? You're a perfectionist and that just won't do? Okay, try this one: set your pans on signals that are all the way left or right to eight and four o'clock, and bump the level up about three dBs higher than you normally would on those sources. In the studio, you should be able to hear it - to the point where you're thinking it's too loud that way. On the air, provided your transmitter processing is not tied together to compress both channels at the same time when an overage is detected on only one channel, the extra bump on the levels should fly by undetected on stereo radios (as a matter of fact it will sound better), as well as solve the problem with stereo effects in mono. Check with your engineer as to how he's got the chain set up.

Coming Down With a Bad Case of Mono

from Rick Allen, Production Director, HOT 97, New York, NY

More people are listening to your great stereo production in mono than you might realize. Are you aware that car stereos have a circuit that blends a radio station's signal to mono under certain conditions? It's a circuit that monitors a station's stereo pilot. The pilot can get "noisy" around tall buildings, in fringe areas, or near hills or mountains. When this happens, a station can sound scratchy. To counter this, car radios blend the right and left channels to mono. Some do this in just a couple of quick steps between full stereo and full mono. Many of the newer models blend in smaller degrees depending on the condition of the pilot. This means that, at any time, you may still see that stereo light beaming away on your car stereo but really hearing something close to mono. Can your production stand up to that?

As our studios become equipped with more and more effects devices, the need to test for mono compatibility is greater than ever. Listen to everything at least one time in mono before it goes on the air. If it doesn't sound right in your studio, a big chunk of the listeners we're all working so hard to impress may just be tuning out.