Apparatus for recording, transmission or reproduction of sound or images; magnetic data carriers, recording discs; compact discs, DVDs and other digital recording media; data processing equipment, computers; computer software; computer peripheral devices; apparatus and instruments for recording, transmitting, receiving, modifying or reproducing sound, images or data; electronic control systems; electronic sound mixing, processing and synthesizing apparatus; electronic controllers; interactive terminals; mixing desks [signal]; data conversion apparatus; apparatus for the processing of sound; apparatus for processing music; sound mixers; signal mixing controllers; headphones; microphones; downloadable software for mixing audio and/or video tracks; software for processing digital audio files and/or video files; software for playing and mixing audio data, video data, and/or lighting effect data; computer software for checking and improving the sound quality of audio equipment; computer equipment for checking and improving the sound quality of audio equipment; interfaces for computers; interfaces for audio equipment; sound cards; carrying bags or carrying cases all adapted for any of the aforesaid goods; electronic publication, downloadable