The phrase "exhaust note" refers to the sound produced by a vehicle's exhaust system. It describes the unique sound or tone that a vehicle makes when its engine runs and lets out exhaust gases. Full definition
The eight - speed automatic fired off silent and smooth shifts, and when you put the hammer down on this car, the engine and exhaust note sound fantastic. (bestride.com)
This adds a deeper exhaust note in a simple, cost effective way without replacing the entire exhaust system. (ecstuning.com)
It sounds OK, but I wouldn't mind a slightly deeper exhaust note. (autoweek.com)