Logic Pro songs sound different when played in Logic Express

Songs created in Logic Pro that contain Logic Pro Instrument tracks may sound different when played in Logic Express.

This happens because Logic Express will substitute a similar GarageBand Instrument for the Logic Pro Instrument (for example, an EVD6 track will be assigned to the GarageBand Clavinet), and the sound settings from the Logic Pro Instrument may not carry over. The degree of disparity varies according to what Instruments or Plug-ins are being used to create the song in Logic Pro.

Conversely, songs created in Logic Express and then opened in Logic Pro will always sound the same.