Do I need to insulate or soundproof my grow room?

Run a quiet fan on a speed controller, hang it with rubber mounts, keep the ducting short and straight, and a carbon filter will take some of the hiss out of the air. Soft bends and flexible ducting hold vibration; stiff, tightly stretched duct acts like a drum.

Insulation only matters at the extremes. In a cold room it helps hold heat. In a hot room it can trap heat, so ventilation matters more. Inline fans, fan controllers and ducting are the parts that make the difference.