I’ve been troubled by deep bass notes from mufflers and stereos for years now. I just found a web site that summarizes a lot of research, and that web site referred to another that also provides thoughtful responses to the noise problem.
http://info.acoustiblok.com/blog/bid/72139/Noise-A-Quality-of-Life-Issue
The first site I found.
http://www.noiseoff.org/
The site the first refers to.
Audio Tool [Google Play]
Excellent sound meter software for Android phones
Online Manual for Audio Tool
http://www.google.com/url?q=https://sites.google.com/site/bofinit/audiotool&sa=D&usg=AFQjCNEaQ93rwgBIV98LSdfEWtFWduEAFg