The HK Audio Premium Pro 10 XD is an active 10 inch PA speaker with a frequency range of 69 Hz to 18 kHz (-10 dB). With the built-in equalizer you switch between a music and speaking mode. This adjusts the speaker according to the usage situation. Do you have a speaker on the floor in the office? Then you switch to the talk mode for optimal sound reproduction for speech. With the bass boost function you accentuate the bass frequencies. This is useful for a party where a DJ plays electronic music. To connect multiple speakers to the Premium Pro 10 XD, you use the XLR Thru output. This makes it possible to put an extra pair of speakers in the back of the room.