Mexico built a nationwide radio broadcasting network in the 1920s such as XEB and XEW, which began broadcasting mariachi music as a media production, rather than as a music for social events. This music was already being modified in part due to the advent of sound recording. For example, most "son jaliscense" songs were longer than the standard three-and-a-half minutes of the then-standard 78 rpm record, forcing the shortening of tunes. Around the same time, the popularity of jazz and Cuban music introduced the trumpet into mariachi, pushing the violins into second place and in some cases, replacing the harp.