Extending the ARC System to Include a Subwoofer

In Part 1 of this series, we discussed the Anthem ARC (Anthem Room Correction) firmware that is present in their SSPs as well as the AVRs which have a  reduced filter bank size. In Part 2, we will discuss the addition of a subwoofer and how it is integrated into the ARC program using the full SSP version of ARC.

By far, the most significant sonic issue for acoustic music when a subwoofer is deployed occurs around the crossover from the subwoofer to the main speaker. Adding a subwoofer to a system using a standard bass management system without a room EQ in the loop (sub and main channels) degrades the flatness of the response in this critical area. At a minimum, the in-room transition band of the low-pass and high-pass filters should track the shape of a fourth-order Linkwitz–Riley (4th order LR – more on these two designers work is below) filter to about 20dB down. With a 4th LR at 80Hz crossover, both speakers are active between 60Hz and 110Hz (-10dB points), a frequency range that is populated with a variety of common instruments playing throughout the score.