I wasn't clear enough, apologies. I meant that my receiver does not produce any additional latency.
It may or may not be a trustworthy test, but I 'benchmark' this using my Wii U and the gamepad. When I play a game like Smash Bros, or Mario Kart (which produce sound from both the receiver and the gamepad), the sounds are perfectly in sync. There's absolutely no echo.
When I play GBA multiplayer games like Four Swords or Super Mario Bros with a friend (I play using GBI SR, my friend has a real GBA), there's a noticible echo going on, which must be the 8-16ms audio lag that GBI has.
I bought this receiver not only for the better sound, but also because my LG tv has HORRIBLE sound delay (video seems to be perfect, luckily).
Hope this clears thing up!
EDIT: Also, I may be very sensitive to delays, but I can also hear the difference in audio delays when comparing GBI SR to a real GBA. I especially notice this when navigating through menus (which produce little navigation sounds) or when jumping in Wario Land 3.