high frequency speaker soviet-made 3gd-31, 5 gdv-1-8 . revision and repair of vintage acoustics

3gd31 abstract amplifier antivibration audio bass car carbon case design disassemble driver equipments fiber frequency gdv18 glue high interior lightweight loudspeaker magnetic media membrane midrange music object paper play power pva repair sealing silk soviet speaker square stereo studio subwoofer system tune tweeter twitter twoway ussr vega vibration vintage white wooden