The sound wave does not care so much about corners as that it's travelling in a cone. Different exhaust routing results mostly from necessity of fitting the properly dimensioned exhaust on the bike, all the pipes are like the 'cigar', just bent into a shape, plus a silencer now days.
If you are interested the exhaust chapter in Gordon Jennings two-stroke tuner's handbook is really good and talks about all that.
"You'll know when you have the design right, because the chamber will then be impossible to fin on the motorcycle without having it drag the ground, burn the rider's leg, or force the relocation of one or more major components".
-Walter Kadeen, former chief engineer of MZ's racing department.