do you need to register the roam under new e mail address on s2?
I keep getting things moving between both apps and causing compatability issues.
too much trouble to just add a wireless speaker imho
No, the Roam and its S2 setup can all be done under the same Sonos Account/E-Mail Address. If you ever get devices moving between the S1/S2 Apps, then you have not got the System split setup correctly and are in mixed mode (S1/S2 in mixed mode have the same HouseholdID)… you ideally need to create one of your Systems as a brand new Household and the problems will then stop and you will no longer have the compatibility issues mentioned.
I suspect most users choose to split their system by upgrading their "compatible only" components to S2 and then they opt to factory reset their S1 devices to create a brand new S1 Household on the same Sonos account.. the important step in the process is starting that new S1 HH from a factory reset state otherwise both remain linked via the HH ID.