Hi-Vi Research B4N 4" Aluminum Cone with Copper Anodizing<br />

Anodized advanced alloy cone (magnesium/aluminum), coated with special damping material
High power handling, heat-resistant Kapton voice coil former and heat-resistant SV voice coil wire
Shielded magnetic system with long-throw linear excursion
Rubber surround

Good choice for small bookshelf speakers.  Often used for multimedia or computer speakers.  <br /><br />In 0.1 to 0.15 cubic foot sealed box you get down to about 85Hz.  A sealed box also has a nice gradual roll off on the low end.<br /><br /><img alt="Frequency response curve" src="https://www.madisoundspeakerstore.com/images/B4N-curve.jpg" /><br /><img alt="Frequency impedance curve" src="https://www.madisoundspeakerstore.com/images/B4N-imp.jpg" /><br /><img alt="spec text" src="https://www.madisoundspeakerstore.com/images/B4N-specs.jpg" /><br /><img alt="Mechanical drawing - 116.5mm outside" src="https://www.madisoundspeakerstore.com/images/B4N-mech.jpg" />