From what i understand the size is not necessarily the thing that make it better. For example High Q driver used in Open baffle designs can have small magnets but smaller gaps in the voice coil (closer tolerances from what i understand are part of what makes a higher efficiency driver hi efficiency).
Magnets got really big in the desire for big bass from small drivers to get the control of the cone and maximize excursion (why small speakers usually need lots of power and damping). Large drivers may not need the excursion so the magnets may be smaller. so magnet size is not a factor in sound quality from my experience, its all in the overall design and intended use.
Maybe a speaker designer will chime in and clear some of this up.
Magnets got really big in the desire for big bass from small drivers to get the control of the cone and maximize excursion (why small speakers usually need lots of power and damping). Large drivers may not need the excursion so the magnets may be smaller. so magnet size is not a factor in sound quality from my experience, its all in the overall design and intended use.
Maybe a speaker designer will chime in and clear some of this up.