The 19" Rackmount hm-800 8-channel headphone amplifier offers up to 10 available mixes with a total of 16 headphone outputs. Perfect for professional applications including studios, houses of worship, practice spaces, and more. Featuring two discrete main inputs with level control Plus stereo outs, aux inputs per channel.Features: two discrete main stereo inputs with separate level control Plus stereo outputs segment LED metering per channel Plus main two headphone outputs per channel eight independent aux inputs for up to eight individual stereo mixes input select and stereo/mono switches per channel 16 total headphone outputs built-like-a-tank construction Specs: audio performance frequency response: 20 Hz 20 kHz, 1 dB noise: -66 dB [hm-400]; 70 dB [hm-800] distortion (THD): 4 dBu, 1 kHz, unity gain; <0.01% [hm-400]; <0.005% [hm-800] maximum levels: main input - 15 dBu balanced/ unbalanced [hm-400]; 19 dBu balanced/ unbalanced [hm-800];; aux input - 20 dBu unbalanced;; headphone output - 550 mW/ channel @ 47 ( 21 dBu) cmrr (main input):> 42 db @1 kHz [hm-400];> 52 db @1 kHz [hm-800] gain range (main input): 66 to 18 dBu [hm-400]; 67 to 19 dBu [hm-800]input/ output input type: female XLR balanced; Female 1/4" Balanced unbalanced main input impedance: 20 k balanced, 10 k unbalanced [hm-400]; 40 k balanced, 20 k unbalanced [hm-800] aux input impedance: 10 k unbalanced [hm-400]; 13 k unbalanced [hm-800] output type: Male XLR balanced; Female 1/4 balanced unbalanced headphone output Impedance: 3 unbalanced power Requirements detachable line cord: 100 120V, 50/60 Hz, 24 W; 220 240V, 50/60 Hz, 24 W AC connector: 3-pin IEC 250 VAC, 10 a male display LEDs front power on/off front input level meter front output level meters L/R mute switches [hm-400] St./ 2-ch switches [hm-400] stereo/ mono switches [hm-800] in 1/2 switches [hm-800]physical properties height: 1.8 in/ 46 mm width: 19.0 in/ 483 mm depth: 8.8 in/ 224 mm weight: 8.0 lb/ 3.6 kg.