You’re not hearing “drone” in any of the previously posted video in this discussion. You’re hearing sound, piped through either your phone, computer or sound system speakers, which really aren’t capable of reproducing the sound dampening and resonance characteristics of your Raptor’s cabin.
here’s a reasonable explanation from an internet search
https://itstillruns.com/fix-exhaust-drone-8080950.html
Exhaust drone is primarily the result of sound waves traveling through the air and vibration that is transferred through a vehicle's frame, body and components. Exhaust drone vibration may also be a result of sound frequency alignment between the engine and exhaust. When the frequencies are aligned, the result is a pressure wave between the engine and exhaust. Sound waves, transferred sound and sound frequency must be controlled to quiet the exhaust. Exhaust system modifications and the application of sound control material will reduce exhaust drone in your vehicle.
There may be other, more eloquent descriptions out there but this one isn’t just good; it’s good enough.
A change in tone generally doesn’t cause and is not “drone”. neither is a change in volume in and of itself. However, when you modify components of the engine exhaust you don’t just change one characteristic, you change numerous characteristics. Reasonable increases in exhaust volume or alteration of the audible tone generally isn’t enough to cause a ‘drone’. A good delineation between changed tone and drone is the former is just a change, the latter is fatiguing. That is to say, drone is bad for your hearing, will cause the onset of headaches, etc. just like an open pipe Hardly Ableson, or a riding mower with no muffler, etc.
it’s possible to introduce a drone with a frequency that mutes normal conversation. Like say, the 302W Mustang GT with flow masters. It was great for when I passed a Yankee Candle factory or craft shop and I could see her talking, but by the time she was able to shout over the drone, we were well past whatever store I really didn’t want to stop at anyway. So not all drone is bad ...
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