moving system of the mid-range speaker 20gds-3 of soviet production. diffuser and magnetic coil speaker

audio equipment mobile system midrange speaker 20gds3 soviet production diffuser magnetic coil suspension repair 20gds 15gd11 basket cap magnet ferrite vintage frequency revision upgrade professional tweeter studio sound technology ussr 35as voice circle bass brick wall abstract broadcast enjoy music retro little nostalgia old 35as012 acoustic stereo background subwoofer recording black