In my experience, audible separation of acoustic events normally happens around 20ms (ignoring phase effects). Most instruments (including guitar) are entirely playable with this sort of delay.
The pipe organ example is a good one - there is a huge variety of delay on pipe organs, probably beyond the half second (I don't have the figures, but there's often a significant delay between keypress and note as well as the acoustic delay). I'm fine with small delays, but fast passages becomes continuously less comfortable as the delay increases. The same is true for other instruments such as guitar. BTW, as I keep moaning, I think network audio is an important "next step" in LAD development and ideally could be combined with the kind of step required to get JACK firmly off the ground. I'm still plugging LADMEA ideas (www.ladspa.org/ladmea/). --Richard
