As long as you get an interface with some kind of "direct monitoring" capability, you'll
be fine. Pretty much all high-end interfaces have this, and an increasing number of
entry-level interfaces do as well. With the MOTU UltraLite, you use the CueMix program it
comes with as a zero-latency monitor.
The UltraLite is a fine interface and
probably has more features-per-dollar than anything else in its class. When I had one my
latency was 7.098ms input, 12.018ms output at 256 samples, which was fine for playing
keyboards live, even without direct monitoring. I mostly only use direct monitoring when
recording vocals. (Also note that interface latency is also tied to your computer, so your
own numbers may differ from mine.)
Also note that each DAW has its own way of
dealing with interface latency. Be sure you understand how your DAW handles things to get
the best results.
Tascam and Roland make fine USB interfaces with around the
same number of I/O as the UltraLite (I have experience with Rolands and they're quite
good), but I believe the UltraLite wins for total number features.
| My DAW Specs