Latency or Echo when headphone monitoring

[bvon]

Macbook Pro 2.5GHz Intel Core 2 Duo
4GB RAM
OS X 10.5.4
Edirol UA-25
Sennheiser 416
Soundtrack Pro 1.1 or Garageband '08

I get either a slight latency or an echo (sort of a hollow echo-y sound as if in a cave) when I'm monitoring my recording through headphones but the recording sounds great when I listen back. No boomy echo at all. I'm inclined to call it latency because it seems as if I can hear my voice mili, nano, pico seconds before I hear them boomy through the headphones. It happens no matter whether I monitor through the Edirol or plugged directly into the Mac and I've heard it using both Sountrack as well as Garageband. I get the same effect if I put the mic in diff. environments or use the computer. mic. Any thoughts on what could be causing it or what else I might do to fix it before it drives me insane? Thank you.

 

[zimv20]

yes, that's latency.

the only way to get a non-latent signal is to tap it in analog before it hits the a/d converters.

possible solutions are y-cables, preamps w/ two outputs, half-normalled patchbays and running through a mixer first (which i wouldn't recommend unless it's a high-quality mixer).

 

[electronique]

Have you adjusted the latency/buffer properties, to allow lower latency?

 

[bvon]

Thanks for the feedback guys. The Edirol UA-25 should allow me to tap into the signal as analog. I may be monitoring after it goes through the computer. I'm not sure. I've tried disabling the software monitoring but when I set it to anything other than the Edirol, I can't monitor from the Edirol. There's a latency buffer setting in Soundtrack Pro but when I adjust it, there's no difference in the latency. You guys have other suggestions?

 

[zimv20]

it looks like that "direct monitoring" knob on the front should allow no-latency monitoring (from the diagram on the top of the unit, it looks like it bypasses the converters, which is what you want).

i'd double-check the manual to ensure you're using it right.

it is possible to get *low* latency monitoring through software, but not *no* latency. the a/d and d/a converters themselves take time, even if the s/w manages to turn it around instantaneously.