license for small audio sample

Hi all,

in my application (Kwave) I have some small audio sample file, which
currently is licensed under the CC-BY-SA-3.0 license, as suggested by
https://community.kde.org/Policies/Licensing_Policy section 11.

Now some packager from Gentoo Linux told me that this is not a nice idea
because it is "incompatible with GPL" and that my application (Kwave)
seems to be the only one that uses this license among all other KDE
applications.

-> So what kind of license should I use instead, any suggestions?

Unfortunately I did not find a clear answer to my question on the
"licensing policy" page on community.kde.org, is that page still up to date?

regards,
   Thomas