[ctrlz]

Recently switched wheels and tires on my car for colder weather. This is on a 2SS. Switch was from 2017 50th anniversary wheels with Goodyear run-flats to 2016 5-spoke Camaro wheels with General AS-05 all season tires. Both sets 20" in stock widths. Tire pressure 35 psi (measured by gauge). About 6000 miles on the run flats, while Generals were brand new.
Noise level measured by app on my android cell phone (Keuwlsoft SPL meter).

At 50 mph on relatively smooth asphalt I averaged 70 dB for the run flats and about 66.5 dB for the Generals.
At 80 mph on moderately worn asphalt (Garden State Parkway) I averaged 72 dB for both sets of tires.
That's the objective.

Subjectively, the new tires sound quieter under all conditions. I did not try to break down the measurements by frequency, but I suspect the 80 mph noise is some combination of drivetrain and wind/cabin noise, and the contribution from the tires is less significant compared to 50 mph.

So I got a 3.5 dB decrease in SPL at 50 mph. To put that into perspective: a 1 dB change would be barely noticeable to most people. 2 dB most people would notice, but not consider a huge jump. A 3 dB difference would be noticeable to just about everyone, and most would consider it a significant volume change. This is my simplification, because hearing is very subjective and frequency is also a factor.

[enzia35]

Yay, science!

I find those tires are pretty quiet, except for the growl that TR noted.