Kontakt plays the MIDI values, etc. that are sent to it--volume being one of them. So, in your case the volume sliders in Kontakt will reset to whatever they are set at in Sibelius. Check it out the next time you play a file. I'm almost certain that this is your problem. As far as I know, there isn't much of a work around other than making sure that you have the volumes set in Sibelius the way you want them to sound in Kontakt.
Anyone else want to chime in with a prescription rather than a simple diagnosis? :-)
Legacy Forum Post
about 15 years ago
That solved it for all of my sounds except for my Garrittan Personal Orchestra samples. I have an email out to their tech support, so we'll see. Thanks man!