matching impedance and maximize the speaker’s output
You've got it backwards.  You have a 600 &Omega; signal and want to drive a 8 &Omega; load.  Apparently you are trying to do this with a transformer between the two.  Clearly the primary needs to have the higher number of turns.

Your resistance ratio is (600 &Omega;)/(8 &Omega;) = 75.  The turns ratio needs to be the square root of that, which is 8.66.  (50 turns)/8.66 = 5.8 turns.  That's what the secondary should be.