In compound time signatures, each beat is divided by three into equal groups of dotted notes, such as 6/8, which contains two dotted quarter note beats, or 9/4, which contains three dotted half note beats.

In classical music, 6/8 should always be a compound time signature. But, in modern progressive rock music, you might find examples of 6/8 which are intended to be considered as a regular time signature.

To accommodate both options, PolyNome has a "Compound Sig" button which can be turned On or Off.

This is a global preference that will affect any new time signatures added until it is changed again.

The button will appear when setting a time signature on the main page if you select a time signature that could be considered compound.

If you're in the "Add Items" view of the Playlist page, you need to tap on the time signature in order to see the button. (Doing this will also allow you to set an irregular denominator for the time signature if you so wish)