9:3 And as he journeyed, he came near Damascus: and suddenly there shined round about him a light from heaven:

9:4 And he fell to the earth, and heard a voice saying unto him, Saul, Saul, why persecutest thou me? Acts 9:3-4

9:7 And the men which journeyed with him stood speechless, hearing a voice, but seeing no man. Acts 9:7

In the above account of the Apostle Paul's conversion near Damascus the men traveling with Paul heard a voice.

22:9 And they that were with me saw indeed the light, and were afraid; but they heard not the voice of him that spake to me. Acts 22:9

In the verse above it reads the men traveling with Paul heard NOT the voice. This apparent contradiction may well be resolved in the next verse to be examined.

26:14 And when we were all fallen to the earth, I heard a voice speaking unto me, and saying in the Hebrew tongue, Saul, Saul, why persecutest thou me? it is hard for thee to kick against the pricks. Acts 26:14

In the above verse it may be significant that Paul heard the voice in the Hebrew language. It may be that the men traveling did hear the voice, but that they heard not may mean that they did not understand what was said. It could be they didn't understand the Hebrew language.