7/10 the most intriguing new audio technologies that you've probably never heard of. Using a new, more efficient type of Bluetooth, it promises lag-free, high-quality sound transmission from up to 100 meters for a limitless number of devices. It has a ton of potential: Someday, we may tap into Auracast broadcasts on our phones in places like airports and gyms to get a private listening session from public TVs, like a cross between Wi-Fi and FM radio. For now, compatible devices are sadly scarce. That's what makes Sennheiser’s new BTA1 TV transmitter so special. This little block is loaded with inputs, designed as a sort of bridge between Auracast and virtually any TV. Where most traditional TV headphone systems use older standards like radio frequencies or a 2.4-GHz signal to send wireless audio to dedicated headsets, the BTA1 opens things up to any Auracast headphones. The other problem is, most of the best headphones don’t yet support Auracast.…