You will arrive by bus to Nord Station. Go to Arc del Triomf and take the metro (Line 1-Red) and get off at the last stop: Plaça Catalunya. From there take the metro (Line 1-Red) and get off in GLORIES (fourth stop). You will go out to a very big square. The easiest thing os to go to the Agbar Tower (the big blue tower that presides over the square) and take the street BADAJOZ, that there begins, going to the sea direction. At the second intersection, turn right and take TANGER STREET. After the first crossing (CALLE AVILA) you'll see a passage (small dead end street) to the right. We are there, at number 7!
However, if you have motivation and a nice day, you can come walking from Nord station (15-20 minutes). Take Ali Bei Street towards the Plaza de las Glorias. You will cross these streets: Sardenya, Marina, Lepanto. Keep walking in the same direction and crossing a wide avenue, where Ali Bei Street ends and begins Tanger street, but in practice is the same street. Continue in that direction, cross Pamplona, and on your left you will find Passatge Ali Bei, we are at number 7!