This weekend I drove from GA. to IL.
Newly purchased 2005 Corvette "Road Trip".
My improvements before trip
Peel & Seal, 3 layers in rear cabin, 1 layer on both wheel wells, and 1 layer behind both seat.
The rear cabin was loaded with 2 soft-shell-suitcases, and 3 thick winter coats. The Peel & Seal plus the suitcases and coats should be more than needed to damped my exhaust drove noise problems.
I used a Bruel & Kjaer Hand-held Analyzer Type 2250 (This device is used to measure sound levels at different frequencies in db)
At cruising speed of 70 to 80 mph I measured the following.
40Hz at 102db
125hz at 102db
40hz and 125hz are low frequencies. 96db in low freq in very loud.
I am getting readings of these freqs at 102db. THis is not GOOD to the body.
Frequencies this low can only be filtered by using a large solid mass that will not resonate.
Most filter materials used will only help with the higher frequencies and road noise. My corvette is like a giant sub-woofer mounted on rubber tires. Everything in the car is resonating at these freqs. Plus the shape of the rear window amplifies the effects
Some components of low freq can not be heard by the human ear but can still cause some damage to your ears if exposed too long. My car caused my "ear to jaw" to hurt after 6 hours of driving...I am only 49 year of age.
The exhaust system in my car is "engine to cats to resonators to straight pipe". TOO LOUD.
Solution for me....Going back to OEM.