1 x 26mm high frequency with metal dome, high temperature voice coil and fluid cooling 1 x 200mm bass/midrange with reinforced polypropylene diaphragm and 31mm high temperature voice coil on Kapton® former
These are 2 ways speakers with the bottom driver being a passive bass unit in a sealed unit which means that there are no base ports.
They do sound better sited away from walls and definitely don't place them in the corners of rooms otherwise the bass loses focus and can sound muddy and slack. There's plenty of power and control from the 620's with a crisp, clear top end. Very capable of playing all types of music and enjoyable to listen to.