I've found the opposite to be true. Got a pair of QC-35II that block everything but speech, which subjectively appears to become even louder, even when you listen to music.
They're great for airplanes, trains, and low-frequency background noise, but for a crowded office where people are having chats and telcos, I'd rather use Shure in-ear monitors.
They're great for airplanes, trains, and low-frequency background noise, but for a crowded office where people are having chats and telcos, I'd rather use Shure in-ear monitors.