CPC Subgroup
G11B 3/74 Multiple output tracks, e.g. binaural stereophonic
Full Title
Recording by mechanical cutting, deforming or pressing, e.g. of grooves or pits; Reproducing by mechanical sensing; Record carriers therefor (G11B11/00, take precedence) > Record carriers > Groove formations, e.g. run-in groove, run-out groove > Multiple output tracks, e.g. binaural stereophonic