Take the subway to Sangsu station on Line 6 (exit #1) - double back on yourself keep going straight towards Hongik University. Take a left onto the street before the 7-Eleven. Walk straight along that road about 30m - you will see Club Ta on your right.
One of the original Hongdae live cubs, Ta is a fantastic basement club in the middle of Hongdae. Always has high quality bands playing from all genres.