If the DSL is not filtered at the master socket it will be running around your house and picking up interference. Some of this comes from the ringer circuit.
Also you want to filter the DSL as close to the exchange as possible to get the fastest speed.
Another point to note is if you do use microfilters you may want to swap them out, the components in cheap ASDL filters may not be rated for the higher frequency of VDSL.