Being unhappy with my new Firewire 410 - even with hardware monitoring, I felt some unpleasant delay when playing a guitar or singing - I decided to make a comparative test. So I measured the so-called "zero latency" feature (sometimes more prudently called "near zero") on 3 external audio devices I own, namely : Emagic EMI 2/6, M-Audio Firewire 410 and Edirol UA-20. The results are frightening : - Brand new and over-hyped M-Audio interface, besides its incredibly crappy Mac drivers, has a hardware latency of 120 (!) samples, whatever analog input you're using (mic preamp or line in, so this is not caused by the preamp) - EMI 2/6 is twice better, but still far from "near zero" : 60 samples. - Edirol wins the first price of honesty : zero samples ! This proves that real zero-latency monitoring is possible, even on non-expensive hardware. But don't conclude that the UA-20 is the best option for Logic : at least with its current Mac drivers, software latency is too high. Tests were very classical : I recorded a 48 khz stereo audio file in Logic, using my Powerbook's built-in audio. Source was a guitar (mono) connected to a Y cable, one branch of it being directly plugged into the Powerbook's left in, and the other one going through the tested gear (with software monitoring de-activated) before reaching the PB's right in. Checking the recorded files with a big zoom factor made it possible to actually "see" the delay between L and R signals. Yann Le Bihan PS : I would be interested in knowing the results on MOTU Firewire interfaces.