Rosh Chodesh music fest

I spent the evening listening to the Moshav Band's latest recording, "Misplaced." I thought Elf's logic made sense (see comments to this post)--you can't say Hallel and mourn at the same time. As my favorite quote from Hallel says, "Ze hayom asah HaShem, nagilah v'nism'chah bo, This is the day that the L-rd made, let's rejoice and be glad on it."