Codecs are a bit like vitamins. They’re essential for things to work properly but only professionals really need to know much about them. That said, it’s worth noting that B&W’s new PX7 headphones (£350) are the first to use Qualcomm’s new aptX Adaptive Bluetooth, which promises 24-bit/48kHz transmission quality and low latency. To normal people, that means they sound better, especially with their 43mm drivers, and with a promised 30-hour battery life they’ll play for longer between charges too. The PX7s are over-ears but if you’d prefer on-ears there’s also the PX5s, with smaller 35mm drivers and 25-hour battery life for £270. Both have three levels of active noise-cancelling and will be available to buy next month.