Edifier R1000TCN V14 2.0 Bookshelf Speakers (Black) Housed in 100% medium-density fiberboard (MDF), this R1000CTN bookshelf speaker is built to resist resonance. Featuring 4" bass drivers and 3/4" silk-diaphragm tweeter drivers, R1000TCN bookshelf speaker is engineered to deliver commanding sound with subtlety and details. For a personalized listening experience, you'll find the bass and volume adjustment dials at the back of this bookshelf speaker. R1000TCN also features dual stereo line-in ports, with dynamic treble enhancement on port A.