528EFront_300Microphone processing is one of those things that most broadcasters know about, but it seems mysterious to those new to the industry.

When we say “mic processing”, we don’t mean that it will change the voice to suddenly sound like Darth Vader. We are concerned with controlling the overall level of the voice, minimizing background noises, and a few other things.

In the course of an ordinary conversation, your voice may go from very quiet (almost a whisper) to extremely loud (when you get really excited about the point you are making). The problem is, the person listening to your program is not usually able to deal with the full range between soft and loud. The listener is usually in a car or office, with other distracting noises around them. In order to hear you at all, your voice needs to be maintained at a consistent level, and not allowed to drop very far from that level.

The mic processor’s job is to ensure that, when you are speaking loudly, your voice does not exceed the level that the equipment is designed to pass. This prevents a distorted sound. At the same time, the processor brings the quieter parts up to the same level as the loud parts, so when you speak softly, your words are still heard clearly.

The action I just described is compression. But a mic processor does more than merely compression.

When you stop speaking, or take a breath, the background noise of the studio would be clearly heard. A mic processor has a “downward expander” system that effectively reduces the background noise during even brief pauses.

It’s this combination of compression and downward expansion that creates the “bigger than life” sound of a polished radio program. Most mic processors have additional functions that add to the “finished” sound of the voice talent…

Some people have unusually loud “sss” sounds. An ordinary compressor over-reacts to a strong “sss” sound by reducing the level of the voice farther than needed, to the point that the next few words may be too soft to hear. A mic processor treats “sss” sounds separately, with a system called a “de-esser”. It specifically watches for overly loud “sss” sounds, and holds them to a normal level, so the main compressor  circuit can more effectively control the overall sound.

Equalization changes the tonal balance of the voice, by altering the amount of high or low frequencies that are heard. Some mic processors have elaborate equalization sections, while others are more basic. It’s in this section that many users go too far, and cause more harm to the sound than if EQ had not been used at all. If EQ is called for, the amount of adjustment should be minimal for the best results.

Consider this: the microphone you selected for your studio was chosen because of its sound characteristics. You may have heard another one that sounded almost the same, but this one sounded “just right”. If the mic was carefully determined to be “just right”, then why are you anxious to change its sound by altering the equalization settings on the mic processor?

The final process found in many units is the “symmetry control” or “phase scrambler.” On certain (mostly male) voices, a slight increase in loudness can be gained by engaging this process. If the talent is listening to his “processed” voice, the “phase scrambled” effect may be undesirable, and he may elect to not use it. This process is most often used in traditional over-the-air broadcasting. It has little benefit on a non-transmitted format.

So, using a mic processor will ensure that your talent is heard at a consistent level, whether he is shouting or whispering. And the room’s background noise will be reduced.

It’s the first “upgrade” to consider for your new studio.

The most popular mic processors are: Symetrix 528E, dbx 286S, Vorsis M-1, AirTools 2X,  and Aphex Channel.

One thought

  1. Gary;

    I’m giving a copy of this to my announcing staff. They are all “experts” when it comes to tuning audio in their headphones. The best touch you can give something is with a light, rather than heavy, approach to EQ and compression. Also, removing frequencies that are offensive, rather than adding more highs or lows seems to do the trick.

    It is a well-written article, with gobs of great insight into studio technique. Thanks again!

    Lee Roberts, Salem Communications Colorado Springs Chief Engineer

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