I couldnt find any posts online to compare the older original Mavic Pro with the Mini 3 noise levels.   As a simple comparison I am posting these numbers here in case anyone else is looking for the info.  

Measured using a Samsung Galaxy S23 with a noise reading app installed, sitting on a fence with the microphone aimed at the drone   

40dbA Ambient noise in a suburban park with no people around / baseline measurement  

The drone is positioned 4 metres away hovering at 1.8 metres in no wind - the same height as the measurement phone   
60dbA Mini 3
69dbA Mavic Pro   

The mini 3 is considerably quieter   
Its technically less than half the noise level however human sound perception is not on at same rate. But it is much quieter and can hardly be heard at 100m altitude except for when it fights gusts of wind or changes direction.   The Mavic Pro can easily be heard at 100m altitude.

An example is this video
https://youtu.be/EELkGU_NtuA?si=HUYfOUC6TpRm7qTu&t=371
The models are different in the video but the levels are similar and its a very noticable noise level difference.

These mobile apps are not very accurate. Perhaps it is suitable for measuring volume differences, but it would not be suitable for anything else, because it is not calibrated for them

Thanks for sharing this information! It will definitely be helpful for others on the forum. Have a great day! Thank You!

So is the mini 3 one of the quietest drones?