I owned some QC25s for a while and also found that they're useless when it comes to voices. The solution I've found to voices is IEMs, those in ear headphones.

I owned some QC25s for a while and also found that they're useless when it comes to voices. The solution I've found to voices is IEMs, those in ear headphones. I'm currently using a pair of Etymotic ER4SR with the foam tips that came with them and I can't hear a thing when I'm in the office. They're not as good for deep ambient noise like the rumbling of a bus or train engine but I haven't found anything nearly as good when it comes to voices. The stock foam can get a bit uncomfortable for a while though so I'd recommend getting some Comply branded tips, which I find much more comfortable and close to as good. In the end though, I ended up paying for custom molded silicon tips, which by all reports I should barely be able to feel at all, let alone experience discomfort with. Still waiting for them to arrive though.