ImPro MX-9 DSP Karaoke Mixer & Digital Echo Processor – Bluetooth, FBX Feedback Suppression, 4 Mic Inputs, Optical & AUX Music InputsBring the "karaoke room" sound home (or clean up a small venue) with the ImPro MX 9 a 1U rackmount DSP karaoke mixer + digital echo processor built for vocals. You get the controls that matter most to singers: rich echo, smooth reverb, and FBX feedback suppression, plus flexible music inputs like Bluetooth and Optical (TOSLINK) for easy TV karaoke player setups. Why singers love the MX 9 Big vocals without the squeal. The MX 9 is tuned for karaoke