I don't really understand this, why does the transmitter require a high line input level, doesn't it have some gain adjustment?
I'm only posting my observations.
Of course there is volume adjustment on the side of the audiolink pro.
But even with the volume maxed out the achievable loudness when you feed a source like an iPod (also with the volume maxed) is too low in loud surroundings (i.e. a live drummer playing at your side).
With a normal and decent headphone amp before the audiolink (like it should be normal procedure anyway) this will be no problem though.
That's why the unit gets both my thumbs up.