Behringer MDX2200 Composer PRO in broadcast, Protection of a system with a passive crossover

COMPOSER PRO MDX2200

5.2.1 Protection of a system with a passive crossover

If your sound system incorporates a passive crossover network (included in the loudspeaker case), insert the BEHRINGER COMPOSER PRO between your mixing console output and the power amplifier input. It is used as the last link in the chain preceding the power amp. Thus, you can effectively avoid the “technical knockout” of the midrange/tweeter range caused by high-energy bass signals! This statement, as paradox as it may seem at first, can be explained with the fact that especially low-frequency signals with high amplitudes can overload the power supplies in the amplifier(s). The resulting clipping (cutting off of signal peaks) produces high-energy distortion (upper harmonics), which is abruptly added to the midrange/tweeter signals. For this reason, “weak” power amps, in particular, must be protected by a limiter in their “input dynamics”.

5.2.2 Protection of a system with an active crossover

For systems using active crossovers, there are two ways to use the BEHRINGER COMPOSER PRO. The unit may be inserted between the console output and the crossover input. In this application, the BEHRINGER COMPOSER PRO will process the entire audio frequency spectrum.

Alternately, the BEHRINGER COMPOSER PRO can be inserted between the output of an active crossover and the input of a power amplifier. In this application it will only affect a specific range of frequencies. This application is particularly suited to protect the most fragile components of a multi-way speaker system against harmful signal peaks. For example, when your tweeters keep on going up in smoke all the time, the entire system should be operated at lower sound pressure levels or the tweeters should be replaced by other models. Using the COMPOSER PRO in the corresponding tweeter band avoids overloading and thus damage to the speakers.

5.2.3 Improving the sound of a processor system

A processor system is understood as a PA system which contains a special active crossover whose outputs are linked via separated power amplifiers to the loudspeakers. Each band has its own limiter whose task it is to limit dangerous signal peaks to a certain level. This process avoids overloading the subsequent power amplifier or destruction of the loudspeaker.

In some units, the crossover frequencies in the crossover unit are further changed during high signal levels to achieve a “loudness contour” suited to the human hearing. But in many cases, this function leads more to a disturbance than to an improvement of the sound quality.

If the COMPOSER PRO is preceding this system, the signal peaks can be eliminated before they reach the limiters of the processing system. The sound quality therefore remains natural and free of side effects caused by the changing frequencies of the crossover.

5.4 The COMPOSER PRO in broadcast

The main aim of processing sound recordings for commercial radio and television is to achieve a maximum transmission volume at all costs. Owners of these radio and television stations strive to get bigger audience ratings, because principally, radio programs whose reception is louder than the average are preferred by the listener. By achieving a bigger audience, the broadcast station gains more money from the increasing number of promotion companies placing adverts.

What is volume?

Volume is defined as the relationship between the average level of program material to peak-to-peak level, in response to amplitude and duration. The higher the average level and the time it remains at a high level, the louder the program material will be perceived by the listener.

If you want to run your broadcast station at maximum average volume, proceed as mentioned in chapter 5.1.2. Please make sure that the maximum peak level is below the threshold of the transmitter’s limiter, otherwise this could lead to very hard and audible use of the transmisson limiters. Keep in mind that a heavy increase in average volume by means of compression always leads to a loss in dynamics and an increased perception of side effects. The moderate use of the compressor and the peak limiter sections of the COMPOSER PRO result in higher average volumes, free of distortion.

5. SPECIAL APPLICATIONS 23