A retaining feature is provided for connecting a plastic tube to a corrugated acoustic duct. The retaining feature accommodates variations in the undulations and thread pattern of the corrugated duct, while at the same time minimizing the materials, specialized equipment or tools, labor and cost of making a successful connection. The retaining feature includes at least one barb extending circumferentially around the exterior surface of the plastic tube. Each barb is sized and structured to engage an undulation of the corrugated duct.