Bluetooth audio streaming and telephony support The three full-range, multi-channel Kappa amplifiers (K2, K4, and K5 models) feature Bluetooth connectivity for wireless audio streaming from phones and other devices. You can receive phone calls through your car audio system, just by touching a button on an included control panel. Clari-Fi™ audio restoration technology Clari-Fi™, a proprietary DSP technology is incorporated in the K2, K4, and K5 amplifiers, analyzes music files and improves highly compressed digital music files in real time. A predictive algorithm restores audio content that is discarded in the compression process. Clari-Fi™ works with all playback devices and audio sources. It extends high-frequency bandwidth, restores the natural warmth of vocals and widens the sound stage. In short, Clari-Fi™ gives your digital music back its soul. Party Mode wireless pairing The K2, K4, and K5 amplifiers offer Party Mode, a multi-pairing capability that enables Bluetooth devices to stream audio individually. When Party Mode is selected from the cabin-mounted control panel, anyone in the car can drive the music. Cabin-mounted control panel The K2, K4, and K5 multi-channel amps come with a wired control panel that incorporates an omnidirectional microphone and puts a range of functions at your fingertips. You can activate Bluetooth pairings, accept and end phone calls, select Party Mode and cancel Clari-Fi™. Class D amplification Every Kappa amplifier, including the full-range models, is a Class D. These high-efficiency, low-heat amps generate a lot of power without drawing much current, and feature small footprints. Full-range line outputs The full-range Kappa amplifiers (K2, K4, and K5) include full-range line outputs. This enables them to pass the audio signal to additional amps that power subwoofers, increasing your system configuration options. Upgradable firmware Kappa amplifiers incorporate a mini-USB port that enables you to easily upgrade firmware. ADAS Input The full range Kappa amps feature an ADAS input which overrides the audio signal when connected to ADAS accessories. In addition, ADAS alert routing location can be assigned during amplifier setup using the panel mounted control. DBO™ (Dynamic Bass Optimizer) Kappa amps feature a subsonic filter in with variable frequency and Q. For sealed enclosures, set the Frequency Control to 35Hz, and then adjust the Boost Control to your preference. For vented enclosures, set the Frequency Control to 10Hz below the port tuning, then adjust the Boost control to your preference. Sleek design Sometimes, an amp can be as stylish as it is powerful. With brushed steel and screwdriver access concealed by a magnetically attached panel, Kappa amplifiers have a clean, streamlined industrial design.