According to www.londonslang.com, "the word is used especially in police and underworld circles and may come from the Romany word drom, meaning highway, but is possibly a back-formation from drummer, someone who knocks (drums) on people's doors, either to buy or sell goods or find somewhere to rob." An alternative answer (though perhaps unlikely to have been the origin) is that it is rhyming slang - drum & bass - place.