Wrong studio set being loaded when song starts

Make sure you have the latest OS version installed. Then, make the appropriate settings for the Studio Mode you want to use, eventually play the song back one more time to make sure that you hear the right sounds and re-save the song. When you do that the settings of the sound generator are also saved together with the song and they are recalled when you hit the play button. This is why it's a goog idea to leave a little room in the begining of the song (1 measure empty). If you want to start straight from measure 1 then delete the blank measure at the begining, make sure that the Studio Mode is properly configured and you hear the right sounds and re-save the song. Most likely if you leave a blank measure at the begining but start the playback on measure 2 will lead you to a playback wih the wrong sounds.

Thanks G-Man. I do have the latest OS installed.

I realise the settings for the sounds (studio set-up are saved with the song that is how I've been operating. Something must somehow have gone out of sync.

I guess I'll go through them all and resave the song with the correct studio set again though what I don't understand is why the songs loaded with the correct studio set but then changed it when I hit play?

Probably some program change messages are inserted somewhere, or exclusive messages at the begining of the song. You should check that out with microscope mode. Try to set the Studio correctly and playback the song with the right sounds; when the song reaches the end, re-save it (don't rewind before that, stay at the end and see if it works that way). Also, if you have a blank measure at the begining, don't jump to the second one and hit play there; either play from the begining and wait one measure, either delete the blank, make sure that you have the right sounds and re-save the song.