Pictured above: An example of the differences between the larger and heavier (ceramic) ferrite motor on the left. And on the right, the smaller and lighter Neodymium motor. Note the Neo speakers are aproximately 1 dB more sensitive and have triple venting for improved thermal characteristics. The Neo speaker also has the added bonus of video shielding. No stray magnetic flux to effect sensitive electronics. These are all 6.5" woofers.