Fault Modes for High Frequency Compression Drivers
Fault Mode type 1: Impact Damage (leading to damage when unit is energized)
HF drivers can sustain damage when dropped or subjected to high-velocity forces. This can affect the centering tolerances in the voice-coil gap and create out-of-round conditions, or cause other mechanical attachment / fixture failures. If and when this occurs, normal/typical input voltage levels can lead to premature failure due to rubbing, etc.
Fault Mode type 2: Damage from Transient Peaks
HF drivers can sustain damage from input voltage peaks that dramatically exceed the average input signal that is being sent to the unit. Observed damage is typically represented by diaphragm creasing, shattering, or surround separations, etc. Peak limiting thresholds are typically used to prevent this type of failure.
Fault Mode type 3: Excessive excursion
HF drivers can be damaged due to improper high pass filtering in combination with high drive voltage. This can lead to Ferro fluid migration, shattered diaphragms, de-bonded coil/diaphragm joints, etc. This generally does not result in an excessive, average high operating temperature (unless Ferro fluid is ejected from the gap). In most cases the failure is purely mechanical.
Fault Mode type 4: Damage from High Average Operating Temperatures
HF drivers can sustain damage when the average electrical operating level supports a sustained high-thermal condition. Observed damage is typically seen to be failure of wire leads or solder joints (conductive element separations), or displacement of bonded adjacent surfaces due to adhesives. Average (long-term) limiting thresholds are typically used to prevent this type of failure.