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 russia dj retro diffusor decoration electronics wood ussr device back 35 watts object black 35as conceptual box grids vocal lowfrequency voice