Simplify the following text for a Grade 4 native English-speaking person.
Original: The `` Small French Tuba in C '' is a tenor tuba pitched in C , and provided with 6 valves to make the lower notes in the orchestral repertoire possible . The French C tuba was the standard instrument in French orchestras until overtaken by F and C tubas since the Second World War .
Simplified: Most orchestras have a tuba now .