The Peschitta (Aramaic NT) says:

Now the men who were travelling with him on the road were amazed because they heard only a sound, but a man was not visible to them. - Acts 9:7

And the men who were with me saw the light, but did not hear the voice that talked with me. - Acts 22:9


It says they heard only a sound -- not they only heard a sound. The men saw a light and heard a sound, but could not see a man or hear a voice. I see no contraction here.