New music collective sfSound comes to Old First Concerts this week with music by Mathias Spahlinger, a German composer of highly intense modernist music; Brian Ferneyhough; and Ferneyhough students Erik Ulman, an sfSound resident composer; and Matthew Shlomowitz, an Australian composer and student of Ferneyhough who, like his mentor, makes abstract, complexly-patterened music. For all you adventurers out there who like an intellectual challenge, this is the antidote to the easy listening summer pops season you’ve been waiting for.