The subs aren't pushing out bass.
The Kenwood KAC-6202 2-channel is only rated for 60 watts RMS per channel into a 4 ohm load. That just isn't much power for a pair of 12" subs. Even the bridged output is only 200 watts into 4 ohms, still at the low end for a sub, much less to share between a pair of subs.
Assuming that your subs are 4 ohm, you could probably get more sound by driving just one of them on the bridged terminals. But to get the best power with what you have, connect one sub to each channel, set the filter switch to the far right (LPF), set the operation switch to stereo (both channels driven), set the filter frequency (Hz) to 100 or lower, and adjust the input sensitivity as far clockwise as possible without causing distortion.
But, to do the subs justice, you really need at least 300-400 watts to share between them.
Hope this helps.