The owner of this highly-modified 2016 RS7 wanted better audio performance than the Bose system could deliver, but wasn’t ready for a full high-fidelity reference-level system. We improved the performance of the cabin speakers with an Audiotec Fischer  DSP tuning processor/amplifier, and added a dedicated 8-inch subwoofer to augment the low end (with its own, dedicated amplifier). Everything was installed out of sight, and in a reversible manner to allow reversion to stock in future if desired.