Car cabins are small, hard-surfaced spaces that tend to build up bass and let road noise mask quieter details — both classic EQ problems.
If bass feels overwhelming at speed, a cut around 60Hz often helps more than turning down the volume. A gentle boost in the high-mid and high bands can help vocals and detail cut through tire and wind noise on the highway.
Road and wind noise increase with speed, which is why a curve that sounds balanced parked in the driveway can feel thin on the highway — if you tune while stationary, expect to nudge the high-mid band up slightly once you're actually driving.