The filter suppressive STF-1 was specifically designed to eliminate noises, whistles, etc …, that perchance appear on the speakers, with the car running after installation of sound.
However, the filter STF-1 will act only in noises that are entering in the amplifiers or CD-Player/MP3-Player through positive pole (+12 V).
The STF-1 filter will not act on static noises that are induced by antenna or housing of CD-Player/MP3-Player. In this case the problem can be solved using suppressive cables into the engine manifold.
Especially developed for use in conjunction with power amplifiers, the STF-1 allows the passage of high current peaks, when required, thus the main disadvantage of most filters, which is the “lock” of the peaks of energy is eliminated . The problem exists only in very high volume, next to distortion .