I’m kicking back listening to my bridged mono AHB2’s :)
And there it is, protecting ones self interest regardless of the facts for others.
Yes you need bridged ones with your speakers (attached).
But the OP does not, and he’ll get better sound with just 1x stereo one.
ATC SM19 Lab Report
" Average sensitivity (considering measurements in octave steps between 125Hz up to 16kHz) is close to 83dBSPL/2.83V/1m, a performance that undoubtedly classifies the SCM19 as a low-sensitivity loudspeaker,"
"SCM19’s impedance magnitude variation is quite small for frequencies above 100Hz and as an amplifier load is -for all purposes- constant. The minimum value of about 5.6 Ohm appears near 150Hz and allows us to conventionally consider the loudspeaker as an 8-Ohm load, although -typically speaking- a correct designation would be 6 Ohms. Below 100Hz, impedance magnitude significantly increases up to 50 Ohm, a behavior which could affect amplifiers with low damping factors. Also, phase behavior, ranging from +47° to -57° could be quite punishing for small amps."
http://www.avmentor.net/reviews/lab/2016/atc_scm19/display/atc_scm19_impedance.jpgCheers George