I don't see how it's possible to win ANC against loud, booming, tiny reproductive bits car stereos driving by wannabe cholos because the speaker size to produce phase-canceling mirror sound would have to be 10-12" / 25-30cm and placed probably on 3 sides minimum... say 12 speakers or 24 for all 6 sides. And the SPL of the ANC would need to be sized proportional to the most powerful car stereo one wished to block.