JBL JR310 Kids on-ear headphones

The JBL 4320 series studio monitor was introduced through Capitol Records in Hollywood and became the standard monitor worldwide for its parent company, EMI. JBL's introduction to rock and roll music came via the adoption of the D130 loudspeaker by Leo Fender's Fender Guitar Company as the ideal driver for electric guitars. In 1969, Thomas sold JBL to the Jervis Corporation (later renamed Harman International), headed by Sidney Harman. The 1970s saw JBL become a household brand, starting with the famous L-100, which was the best-selling loudspeaker model of any company to that time. The 1970s were also a time of major JBL expansion in the professional audio field from their studio monitors. By 1977, more recording studios were using JBL monitors than all other brands combined, according to a Billboard survey.