Reason to take you to a round of GD is to test your soft skills in areas of communication, leadership, interpersonal coordination etc.
Voice and the way you speak matters a lot. Your voice modulation with pauses will impact to the receptivity of audience. Great voice quality with limitation of sound will attract others to hear you.
You will be dependent on your communication skills cent percent in GD. The more you speak better, you may get chance to lead the group.