Hopefully, the suttle changes in engine sound will be enough to signal my brain, throttle position. This is an area of many potential complaints.
In heated dogfights, it is very possible to forget you have chopped throttle, and I personally have come accustomed to engine sounds reflecting airspeed to a greater degree than an actual pilot.
I do pretty much the same with my truck engine sounds, when changing gears. I guess I also look for visual clues and tire and wind sounds in combination, but rarely look at the speedometer.