Incorrect, WiiM applies a low pass filter to the sub out as well as a high pass filter to the speaker out under its bass management functionality. It also has separate delay control for the mains and for the sub as well as separate volume level control for the sub out (relative to mains, so it goes up and down with the main volume). The problem with the delay control is that it is only in whole ms increments, which is not very granular. Additionally, there is no slope control, only selectable crossover frequency.