Vehicle NVH performance target setting and cascading

A: That's the most common mistake — assuming it's about convenience. Fixed mic locations exist so vehicle-level targets can be decomposed and traced back. If locations float, cascade math and correlation collapse fast.

A: That's the most common mistake — blaming structure when the BIW data is clean. A cascade error that underweights airborne contribution will pass modal checks and still miss cabin SPL right where openings dominate.

A: That's the most common mistake — overthinking the structure. Wind noise targets live and die on sealing performance, and compression set quietly erodes the cascade long after SOP.

A: That's the most common mistake — trusting rig compliance blindly. A damper can hit its curve on a bench and still inject noise if installed wrong, breaking the cascade at the interface.

A: That's the most common mistake — thinking engineering convenience drives it. A-weighting exists so the vehicle-level target reflects human response, then you decompose it with linear data downstream.

A: That's the most common mistake — treating tolerances independently. NVH doesn't care about individual pass/fail; stack-up can move modes right into trouble even when drawings look clean.

A: That's the most common mistake — equating heavy with quiet. Absorbers work by impedance matching, and flow resistivity is what lets the cascade actually close in the mid-band.

A: That's the most common mistake — comparing apples to oranges. A 2 dB margin disappears fast if the supplier reported linear SPL and the vehicle target is A-weighted over a different band.

A: That's the most common mistake — hiding behind the print. NVH target cascade is a system promise; when stack-up erodes margin, DFMEA action is justified even if GD&T is technically met.