this is to adjust a desired operation at a certain moment such as the bass frequencies treble frequencies volume etc between every area of the row 108 a resistor is arranged by silk printing or by using a miniature chip resistor 110 and only the outer areas 109 of the row have been connected to the preamplifiers and further to the microcontrollers when necessary the layer 107 can either be of this plastic layer like polyester or polyimid or of thin circuit board material however a hole 93 has been arranged in the place of each area 106 from which each area is coupled electrically to the lower surface 92 on the lower surface 92 there is arranged preferably by silk printing a transparent isolation layer 90 on the conductors the ground plane 89 in the embodiment is utilized for noise protection and can be printed on the isolation 90 or it can be arranged on the surface of its own plastic film 88 if the resistors 110 used are high it is preferable to use under the layer 107 a layer like 87 which is preferably corresponding to the layer 98 i e holes 85 have been cut into it so that the resistors do not cause any bosses all the necessary conductors 91 are preferably arranged in one place further to a band 117 at the end 118 of which connectors 119 can be crimped for coupling to a preamplifier when necessary all electronic components can be arranged into the same structure by arranging enough space all the electronics needed by the signal processing unit can be accommodated on the lower surface 92 thus a multiple layer circuit.