JBL Reverse Polarity
In the golden olden days of speakers, the issue of whether the first motion of a cone was inward or outward, or polarity, was not uniform. Eventually it became standardized. Most speakers have an initial outward movement. When JBL started making speakers, they arbitrarily adopted reverse polarity and their speakers had an initial inward movement. This continued until JBL developed their musical instrument series speakers which used ¼” jacks. The use of these jacks required that JBL change their polarity to fit into what had become industry standards. Therefore, many of the older JBL speakers have reverse polarity, while newer models match what has become the industry standard.