Never said the physics will change Just provider rule sets or they frequency plans uses different power levels, e.g. care little for AM radio, or AM lobby got it cut even lower

The ADSL2+ would do it, but so will Multimode.

Please can you clarify what country this connection is in? It is hugely important, because all the suggestions we are making assume the UK. Different countries have different setups, as another poster has pointed out. I in particular could be talking junk if you aren't in the UK.