Dayton Audio TCP115-4 4" Treated Paper Cone Midbass Woofer 4 Ohm The TCP115-4 combines a large motor, 1" 4-layer voice coil, vented pole, and a sizable rubber surround to make use of its 4 mm of XMAX. This combination of features makes it a very versatile driver which can be used as a bass driver in a small 2-way system, center channel, or even portable Bluetooth speaker designs.