"Reasonable proximity" refers to being reasonably close or nearby to something or someone. It means being at a distance that is considered sensible or practical. Full definition
This feature determines a user's geographic location and returns a list of science centers and museums within reasonable proximity of that location. (educationworld.com)
That being the case, you'll want relatively flat ceilings in reasonable proximity to the listening area to get the most from this system. (digitaltrends.com)
However, occupancy «as the veteran's home» implies that the home is located within reasonable proximity of the veteran's place of employment. (biggerpockets.com)