Got this off the Sonic Site...
"Starting Sonik Synth 2 in Logic Pro/Express 8."
Launch Logic. Go to File/New/Empty project, for example.
When the New Tracks windows appear, type 1 on the Number box, then select Soft Instrument from the Type options and click Create.
In Instrument 1 track, click on I/O and go to AU Instruments/IK Multimedia/Sonik Synth 2/Stereo.
In Sonik Synth 2, open an instrument folder and double click on a desired instrument.
To monitor, just click on the virtual keyboard or play via your MIDI controller.
To record, click the REC transport button and play your MIDI controller.
To set up Sonik Synth 2 as multitimbral instrument, just enable the Multitimbral check box when the New Tracks windows appear.
- In Instrument 1 track, click on I/O and go to AU Instruments/IK Multimedia/Sonik Synth 2/Multi Output (16 x Mono), for example.
- After Sonik Synth 2 interface opens, select and open an instrument per each of the 16 parts. Logic 8 will sequentially route each of the 16 tracks to the related Sonik Synth 2 parts.
FAQ ID: 1772
Does this help... ?
Lookig at their Website it appears you have to register your product and get and install the latest version of it for Intel Macs...
If you have done all this and it still doesn't work they suggest getting in contact with IK Multi Media Tech Support....