Both the barbell row and the dumbbell row are exceptional exercises for building a thick, wide back. The debate about which is superior misses the point - each has specific advantages that make them valuable in different contexts. Understanding what each does well helps you programme smarter and build more complete back development.
The barbell row allows heavier loading, making it superior for building overall back strength and thickness. You can load significantly more weight than a dumbbell, which creates more mechanical tension and drives greater strength gains over time. The bent-over position also works your lower back and core as stabilisers, making it a more demanding full-body movement. The downside is the technical demand: maintaining a neutral spine under heavy load requires good mobility and practice.
The dumbbell row (specifically the single-arm variation supported on a bench) allows greater range of motion, since each arm moves independently without the bar limiting depth. This extended range of motion creates more stretch on the lat, which many lifters find produces better muscle growth. The supported position also removes lower back strain, making it safer for those with back issues. Use the barbell row as your primary rowing movement for strength development, and the dumbbell row as an accessory exercise for feel and range of motion. Done together, they cover all bases for complete back development. Both work best with a full range of motion, a controlled tempo on the way down, and a brief pause at the top to maximise muscle contraction.