The tuba player was exhausted

When a musician who plays the biggest, lowest-pitched brass instrument is described as 'exhausted,' it sets the stage for some classic musical wordplay. The humor here hinges on the double meaning of the word 'low.' On one hand, it perfectly describes the tuba's signature sound – deep, resonant, and truly 'low' in the musical register. On the other, 'feeling low' is a common idiom for being tired, down, or lacking energy, which perfectly fits an exhausted person.

But there's more to this joke than just a clever turn of phrase. Imagine lugging around a tuba, which can weigh upwards of 30 pounds, and then blowing enough air to produce those powerful, rumbling notes. It's a serious workout for your lungs and diaphragm! So, a tuba player truly could be physically 'low' on energy after a performance, making the punchline even more relatable for anyone who's ever tried to get a sound out of one of these magnificent beasts.