Final answer:
Brass instruments with valves, such as trumpets, trombones, and tubas, have tubing that is coiled into circular loops in order to produce low frequencies. The coiled tubing allows for a more compact instrument while still maintaining the necessary length.
Step-by-step explanation:
Brass instruments with valves, such as trumpets, trombones, and tubas, have tubing that is coiled into circular loops.
These loops are necessary because the tubing required to produce low frequencies, like those produced by tubas, would be too long to be practical if left straight.
The coiled tubing allows for a more compact instrument while still maintaining the necessary length to produce the desired low frequencies.