Take a look at this picture of the Japanese war tubas.
I was shocked when I learned that these crazy tuba looking things ever existed.
Unfortunately, these enormous tubas were not used to make music.
Instead, they were used as "acoustic locators" before the invention of radar.
In fact, these tubas didn't make music at all, rather they were used to listen.
From mid WWI to the beginning of WWII, these "tubas" would amplify the sounds of incoming aircraft.
By listening to the airplanes, the Japanese had a better idea of where the enemy was.
Once radar was invented these contraptions became obsolete.