ATC SCM45A Reference Monitors Added to Patrick Leonard's Return to an Analog Workflow. Patrick Leonard has enjoyed a long and distinguished career as a producer, composer and keyboardist beginning in the 1970s and early 1980s with keyboard gigs and tours with Frank Zappa, The Allman Brothers Band and Michael Jackson. From there, he began an extended tenure with Madonna, helping to write, produce, and perform on her albums True Blue, Who's That Girl, Like a Prayer, I'm Breathless, and Ray of Light and directing and/or performing in several of her tours.