Makes sense though when I TL'd the mustang 34 was my loudest freq tuned at 33 hz... but since then I've reduced internal volume and subsequently raised tuning (by how much I'm not sure, but I did do it in steps). any insights besides cabin accoustics? In modeling, the lower the enclosure volume, the less peak the zcon has. A lower tuning along with less volume should help flatten out the response, but cabin gain will still be present, and I'm not entirely sure you would be happy with reducing this peak of output, after all, you walled your car. The issue is that the peak is SO big, any pther songs just fall short.