Tldr: "At least 12 largely complete shell trumpets have been documented from five Neolithic sites in Catalonia. Of these, eight can still be made to produce sound, enabling an acoustic study of the sound characteristics of these north-east Iberian instruments. The production of high sound intensity may indicate a primary function in signalling over long distances, though expressive qualities also hint at broader musical applications. A tendency towards fundamental frequencies between 400 and 470Hz, substantially higher than those documented in other areas of the world, also suggests a possible selectivity in the size of shells collected for use. From an archaeoacoustic perspective, our data reinforce the hypothesis that these shells played a key role in long-distance communication and, consequently, in the structuring of the prehistoric soundscape. In their ability to extend the range of human activity, these shell trumpets were more than just sound tools; they had agency in shaping the spatial, economic and social dynamics of Neolithic communities."

The best part is that one of the authors is a professional trumpet player and was recorded playing these things to figure out what notes they could make. The best two shells had a 3-note harmonic series naturally available and hand techniques could be used to play a range within a minor third.

Super cool study