I couldn't tell there. Since my brother was asleep in the other room while I was watching it, I had the sound muted and relied on the captioning. I have to agree with Drtooth's post. Since Carroll is still credited as both BB and Oscar, he'll probably at least be dubbing in the voice for a while. I guess they didn't feel that was necessary for such a small role. In fact, and correct me if I'm wrong on this, but it seemed like Matt also voiced BB in the episode with Telly's alphabet collection from a few seasons ago. He seemed to sound a little different there.