I know what it is, i've read about it, but there is one thing i don't know : Depending the vehicle, does it change drastically? Also, qhere can i find out what my freq. is?? I drive a 94 ext cab ranger. Thx guys.
hook up a box in your truck that sealed, run a sine sweep or through the system. have your mic reading with the rta. this will show you peaks in your system, whichever note is highest on the spectrum analyzer. your resonant freq. is a termlab comes with its own dta program. http://www.termpro.com/storefront/Page605.html