simple two-way loudspeaker
In this design of a simple loudspeakerenclosure an attempt hasbeen made to achieve a reasonablygood quality with a minimum ofmaterial. In spite of inexpensive drivers,this aim was met.The cross-over filter has a 6-dBroll-off, which means only one componentper driver: L1 for the wooferand C2 for the tweeter. There is alsoan impedance-correction network,R1-C1, for the woofer, which ‘flattens’the rising impedance of this driver.
There is an attenuation network,R2-R3, to match the volume level ofthe tweeter to that of the woofer.Note that owing to the positionof the drivers, the polarization of thetweeter must be the opposite of thatof the woofer.The unit may be used as a rearspeaker in a surround-sound systemor with a multimedia computer. Inthe latter case, it must be placed wellaway from the monitor since themagnets of most inexpensive driversare not screened.The bass-reflex enclosure (Figure2) has a volume of 4.5 litres. Thebass-reflex port is is a standard40 mm dia. PVC pipe, 175 mm long(if its walls are 2 mm thick; if theyare 3 mm thick, the length must be150 mm). Te material used for theenclosure is 8 mm thick chip-boardor similar.