Matthew 20:29-34
Two blind men who sat by the side of the road heard that Jesus was passing by. I've never been blind, but in the great crowd that was following Jesus, I imagine it would have been difficult for a blind man to pinpoint exactly where He was. They couldn't just walk up to Him, because they couldn't see Him. With the noise of the crowd, they could hardly hear His voice, and couldn't be sure that He would hear theirs. I picture them yelling "Lord! Have mercy on us, Son of David!" at the top of their lungs, just hoping to get His attention. The crowds tried to silence them because of the commotion they must have been making, but they continued with renewed enthusiasm. To their surprise, (or to their faith), Jesus approached them and healed them.
I don't think it was their loud noise that drew Jesus attention, but rather their faith. Their faith became evident by their persistence, merely reflected in their volume. They put it all on the line, even enduring public ridicule, in order to get Jesus' attention, and then made their request known plainly to Him. I believe He responded to their faith (as Jesus often did) and had mercy on them. Their response proved that they were genuine - they got up and followed Him down the road.