You first need to decide on what type of enclosure you will be employing. Sealed box woofers are VERY different from those used in a vented alignment. Other things to consider are what size of driver you are looking for, what type of music you will be listening to, and your price range. Domestic(US) woofers are much cheaper than most European brands. And not always inferior. For a sealed box, I have found success with Audio Concepts(EXTREMELY underrated), Dynaudio, and Eton. Good vented woofers are manufactured by Focal, Madisound, Peerless(underrated), and Swan. Please let us know more about your design, if you want more specific information.
