Upgrading my sound – the Sennheiser CX 400BT review Smooth sound, and a lovely on-ear fit – My ears thanked me for trying Sennheiser’s CX400 BT. I’m doing something a little different for this post. Given the Teams-Time I’ve put in this year, I thought I’d do something for my ears. And when I was offered a chance to review Sennheiser’s new wireless earphones, I jumped at it. Let’s start with the basics. Sennheiser makes good audio equipment. I own…