woofer 75gdn-3 sealed with adhesive plaster. repair and restoration of the speaker

70s 75gdn3 acoustics adhesive adjust assembling audio broken business car change connect damaged diffuser door dynamics equipment flexible flux glue glued hand iron machine magnet mechanic mesh modern monitor music off plaster professional protection radio recording repair restoration rip rosin soldering sound soviet speaker spool studio suspension tool transport ushatanny ussr wire wooden woofer workshop