In reverberation enhancement systems (RESs), sound is constantly fed back from multiple microphones to multiple loudspeakers to enhance reverberation artificially in the target room. This contribution shows that such a system can be understood as an extended feedback delay network (FDN). A tuning process, similar to that of the FDN is presented, allowing arbitrary frequency-dependent reverberation elongation. The cross-talk between the loudspeakers and the microphones leads to comb filtering and isolated ringing modes in the RES, which produce undesired metallic and rough sounds. To mitigate these undesired effects, a cross-talk cancellation system is integrated in the RES. In a simulation example, the benefits of cross-talk cancellation is evaluated.