Should you wonder how it sounded like, please visit John Kenny's webpage on myspace.com: http://www.myspace.com/carnyxco and listen for example to 'The voice of the Carnyx'. It is quite certain that it was never used as a musical instrument (after all it is an instrument of warfare) but it is still fun and you can read some interesting things about its history and reconstruction on his other webpage http://www.carnyxscotland.co.uk/index.htm.
A last thing that is unique to Scottish prehistory is the Pictish period. They produced these marvellous stone stelae:
Although they were made in a basically Christian period they more than often depict pagan motifs. Look at a close-up: