So I brought my e60 (LCI w/Logic7) to a high end knowledgeable mobile audio shop this evening, He went to town quite quickly adjusting the gains, cross-over, and EQ/Tone settings. It sounds much better, but there still is a gap and he pointed it out quite quickly; mid-bass. He said the easiest thing to do is putting in an amp to power the woofers under the seat. In addition he would tap into the front speakers as a source and set the high-pass to 70 (70Hz >). He said the 8" woofers are great for mid bass, but using them for low bass as configured by BMW is not optimal.

Thoughts?

 

If you do that, wouldn't that mean that you have no low-end bass... nothing below 70Hz? That doesn't sound very 'optimal' to me.

plus, having only the high-pass means that you are trying to make the 8" woofer play everything over 70Hz (including the high-end, 20K-30K)... doesn't sound like a very good idea to me.