LDAC is an audio coding technology developed by Sony, which allows streaming audio over Bluetooth connections up to 990 kbit/s at 24 bit/96 kHz. It's about as close to a wired connection you're going to get with today's technology and it sounds fantastic when using good source files (flac, alac, etc). Huawei has a new codec called LDHC / HWA which transmits even higher bit rates but it's not widely adopted and is still a bit unstable. AAC can transmit 1:1 but only if the source file is encoded AAC, so yes it can POTENTIALLY save some battery life but if the source file is not AAC, it too needs to convert. To date there are no wireless earbuds that have aptxHD or LDAC that I can find because those codecs consume more battery and the Buds by their nature have small batteries - so those codecs are not included so as to ensure decent playback time. The compromise of course is SQ. I finally got my self a Shanling UP2 BT DAC and a short 43 cm FiiO cable and now I use my favorite IEMS both wired and wireless. I also ride a motorcycle and both my oBravo Cupids and Shure SE535s fit under my helmet without issue and I clip the BT receiver to my collar. The short Cable doesn't get in the way of anything which is important both out and about and certainly on a motorcycle. The battery life is about 10 hours (way above wireless iems) and the fidelity is incredible (like wired). I wouldn't buy any of the current crop of wireless Buds.... Not to mention the fact that none of that BT microwave energy is being transmitted to my skull. And the BT DAC doubles as a USB DAC and a remote receiver. It's a far more sound worthy, economical and is a far more practical solution than single use iems or cables.