For a soup with a smooth consistency, work with veggies that are soft but not mushy. Additionally, streaming oil or cream into the soup can better emulsify the ingredients for a silkier texture.
Blender features can also play a major role in getting your soup to the right consistency. For instance, the KitchenAid High Performance Series Blender can quickly blend even the toughest ingredients with a range of 9 speeds. Preset recipe programs as featured in the K400 Blender can also produce the texture you desire, from chunky to silky smooth.