"He plays the drums in a band."

Translation: Han spelar trummor i ett band.

[Adelhaidar]

shouldn't "han spelar trummorna i ett band" be a right translation ?

[Zmrzlina]

No. English prefers the definite form in this sentence, while Swedish does not.

[rwhodges]

I wouldn't say that English prefers the definite article: this sentence wotks equally well with or without the. Thanks for the clarification though - it is helpful to know that Swedish does not like to use it.

[Arnauti]

I think we can safely say that it's actually incorrect to use the definite article in Swedish sentences like this one. If you're playing a specific instrument, we'd always want to add a preposition: Han spelar på trummorna works. (not as a translation here of course)