Guy decides to go deep into Africa up the Congo River. After getting to the last easily accessible entry into the river, they board the smallish boat to begin the arduous trek deep into darkest Africa.
A day or three into the journey they start hearing distant drums, then as they continued after some days it got slowly louder. The guy started getting spooked and asks the Captain, "What's up with those drums?"
The Captain replies, "Don't worry. Everything's perfectly fine so long as they continue."
After more days of journeying, suddenly, one night, the drums just stop cold.
Fearfully, the guy inquires, "WHAT DOES THAT MEAN?!"
The Captain replies, "Bass solo."