The perception thing is very real and that is what has driven the German automaker to tweak the sound the doors are making on their cars. Here are a few references. They are recent as this sound engineering has been going on for longer than the newspaper have been reporting online.

* https://www.bloomberg.com/news/articles/2014-08-05/mercedes-... * http://www.bmwblog.com/2014/12/22/perfect-car-door-sound-mad... * http://mediatum.ub.tum.de/doc/1138344/369710.pdf * http://emea.nttdata.com/blog/en/its-all-about-sound-how-car-... * https://hal.archives-ouvertes.fr/hal-00849046/document