Fkelly,
A person who puts music on on shabbos, or who uses any electricity on shabbos, probably can’t be considered a mechallel shabbat, since electricity is not a melacha (neither an av, nor a toldah). The minhag is not to use electricity on shabbos, according to R’ SZ Auerbach. A person who commits an actual violation, such as turning on the flame of his stove, or driving in a car, or carrying, or writing, is outside the pale.