。
Only my seat feels cut off from all that noise.
Literal
My seat alone [subject-が] that commotion [from-から] cut-off [passive-されている].
僕の席だけが ('only my seat') isolates one element using だけ + が. 喧噪 (けんそう, 'noise, commotion') is a literary/formal word. 切り離されている is the passive progressive of 切り離す ('to cut off, separate'). The sentence creates a vivid sense of isolation amid chaos — probably a narrative moment in fiction.