Both modifications make a sound softer. It seems to me that engines, for example are never "muted" but commonly "muffled" while it's the opposite for brass horns. What usage guidance might apply to distinguish between these two in other settings?
For some examples (feel free to supplement), which would I use for:
- a machine that is quieter because it's only heard at a distance through a window.
- a shocked person whose voice is very quiet as a result
- a falling tree/limb cushioned by soft leaves
- a crowded atrium once sound absorption panels have been installed
- a car engine designed to sound quieter to people around it
- a firearm with a noise suppression device
- anything I hear with ineffective earplugs