Quadraphonic System Logo CrewneckHigh quality Crewneck Sweatshirt is made of organic cotton and recycled polyester its slim fit so size up if you want a looser jumper! When audio recording began, there was only one single channel capturing everything. This all changed when in the 1930s EMI scientist Alan Blumlein invented a way of recording sound on two channels, giving birth to stereo. Then came along quadrophonic sound with its luxurious four, yes four channels! Quadrophonic sound