Magnetic field

Hi all,

I'm about to make myself a speaker with two drivers.
I tested them free-air and I (think) the magnets cause problems when they are close to each other, about -5cm. Is that possible?
I used the same speaker, a very cheap FR10 8ohm Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories
in the project. The result is mediocre, but not bad.

The two drivers that are playing in series are a Visaton FR10 4ohm and FR8 4ohm. When I hook them up and compare them to the FR10 8ohm in my Ikea speaker I notice that the Ikea speakers sounds louder. Why?