For version 4 and above, click "Preferences" from the "File" menu. Select "General" and then choose a new temp directory.
For version 3 and lower, you have to go into the registry and change HKEY_CURRENT_USER/ Software/Acoustica/CDBurner/ Acoustica_Temp_Dir to whatever directory you want to be your temp directory. (Note that you should not be running Acoustica MP3 CD Burner at the same time.)
The .ipk are peak temp files which store normalization, trimming and visual data for each sound. The .isk allow us to accurately seek for .MP3 files, especially useful for VBR MP3 files.
**WARNING: Editing your registry should be done with care. Acoustica cannot be held responsible for any damage to your computer. We provide this information to help those who need to change their temporary directory and are technically skilled enough to do it.