Thumping trams, speedboats underwater, creaking moorings

The sound under the Nieblungen bridge can be spectacular. Trams thump and roar as their weight makes the whole structure reverberate and cars rock over the joints in particular spots. But it's not only what can be heard with human ears. Contact mics pick up the creaks and strains in metal mooring ropes that hold landing stages and large riverboats to the shore. And hydrophones can listen into the sound of tourist speedboats from underwater as they zip past. This latter is a loud, persistent (it never completely disappears), cutting whine, an intensely irritating drilling in your ear - real underwater sonic pollution. It can't be much fun being a fish in this part of the river. The recording mixes all these layers together. They were recorded simultaneously in sync.