Personal research material relating to HiFi systems. Includes correspondence concerning Blundell Jones' articles in Hi-Fi News magazine including one entitled 'an asymmetrical loudspeaker enclosure' 1976 and one relating to 'Philharmonie' 1974. Also includes notes and research material relating to speakers, turntables and circuits. Original file labelled 'Early interest in HiFi Systems 1960s and 1970s'.