When Flanner says upgrade, he means that he no longer uses the DD15 and bought a DD15+. There is no upgrade from the old DD series to the new DD+ series. They are entirely different subwoofers.
I have a small room and previously had used the DD10. I now use the DD10+. It is a substantial upgrade across the board.
Disclosure: I am a Velodyne dealer.
I have a small room and previously had used the DD10. I now use the DD10+. It is a substantial upgrade across the board.
Disclosure: I am a Velodyne dealer.