leezone ,

... just to add to what you mentioned above, there is a difference between:-

* OS (the *.mem file Ketron offers for free which is basically the Operating system which controls the features, enhancements and how your AUDYA operates). This file's size is usually in xxMB.

* Extra Sounds (new/modified) and Styles (new/modified) which are what account for the extra xxGB of space usually occupied by the new AUDIO Drums associated with the new styles. These are not really 'part' of the OS but rather 'extra'. In some cases (e.g OS 3.0) they are offered for free and in other cases (OS4.2) a charge could be associated with them.

Any AUDYA (independent of current OS installed) can take advantage of any OS 4.0 and higher without sequentially going through the previous updates. These newer OS files do include the modifications and enhancements found in the previous ones.

This added to Tonewheeldude's explanation above should answer your question(s).

Thanks,

AJ
_________________________
[KETRON - USA]
Design Engineer & Product Specialist.
www.KetronAmerica.com