Tweeter Protector

Tweeters, the high-frequency drive units in a loudspeaker system are often dam- aged by a properly matched and rated power amplifier. This happens because many modern power amplifiers are direct-coupled to the loudspeakers, i.e., they do not use a transformer. Such amplifiers have the nasty property of producing square-wave signals when they are (even slightly) overdriven. The ensuing harmonics lie chiefly in the fre- quency range of the tweeter. This con- siderable spectral shift of the audio signal was, of course, not taken into account during the design stages. This is because during the standard (DIN) testing of the loudspeaker system, the tweeter is required to handle only 1% of the total applied power. In other words, when 100 W of audio power is applied, to a loudspeaker system, the tweeter needs to handle only 1 W. Even if the tweeter is rated well above the standard test specification requirements, during loud music passages, when clipping oc- curs (and square-wave signal...