Sound and optical apparatus and instruments, namely, amplifiers, loudspeakers, high fidelity systems comprised of sound equalizers and amplifiers, pre-amplifiers, power amplifiers, power supplies, digital to analogue converters, crossover systems comprised of modules, namely, integrated circuit modules for stereo loudspeakers, apparatus for the reproduction of sound, in the nature of analogue and digital recordings; apparatus and instruments for use in recording, storing, generating, carrying...