One hypothesis is that we were not hunter-gatherers all the time, but that we tried to do what we needed to do at the time we needed to do it. We hunted and gathered, but at some point we had enough to no longer need to do so. We spent the free time we gained making art and tools (as seen in the Palaeolithic art found on excavations throughout Africa, the Middle East and Mediterranean Europe). We often cut stones with harder stones and rubbed them over the surface until they took the shape that was useful to us (as seen at Lumekwi 3 in Kenya). From then on it was probably only a matter of time before we found stones that made sound.
This is all speculation and I am certainly not in a position to make any claims.
Happens to me too, Sony Xperia 1 V