I have recorded the bag, drones, and chanter with a contact mic and all produce easily visible spectra. I don’t have many pictures yet but below are 2 mp3 files. One is of the contact mic being placed on the outer part of the lower bass drone tuning chamber, where my head falls if I lean over. Another is a few tunes with the contact mic on the chanter, you can hear the pops when my fingers hit, the mic clamped between low A and the tone holes.