I had a different experience. I own taotronics tt-ba09, trond bt-duo x and avantree audition pro headphones, all of which claim to support aptx low lantency. Here is my testing result: a) When I paired either of the two transmitters with avantree headphones, the latency was minimum, and the white light on headset indicated aptx LL active. Obviously both taotronics and trond support aptx low LL in the TX mode; b) I paired taotronics in TX mode with trond in RX mode – NO LAG either; c) Then I made the switch and paired trond in TX with taotronics in RX. The lag suddenly became very noticeable. The conclusion seems quite obvious that taotronics tt-ba09 doesn't support aptx LL in RX.