Alesis MultiMix12Firewire Frequently Asked Questions Manual page 13

I hear high-pitched screeches, static, wrong-speed playback, or other bad
things
Adjust your latency settings in the MultiMix control panel. You will find this
panel in Windows under Start, All Programs, Alesis MultiMix. In Mac, the
control panel is under Preferences or through Audio MIDI Setup.
For more information on latency, see the next topic.
What is latency, and what are the best latency settings to use?
Latency means delay. All digital signal processing requires a bit of latency. For
instance, the signal that you send to the mixer via a microphone or synthesizer
must get translated into a digital signal. That requires a little bit of time.
In terms of recording, latency is measured as the time it takes for digital data to
travel between the computer and the MultiMix.
Setting the latency low
Latency can be set very low, which lessens the delay between the two devices but
makes the computer work harder to process the data at the very microsecond that
it is received. Latency settings that are too low yield crackling audio and
computer instability.
Setting the latency high
If you increase the latency, the delay you perceive will be increased, but the
devices don't need to work so hard. That leads to more stable operation. Also, it
usually allows you to pile on more effects to your computer audio tracks.
However, if you set the latency too high, you can also experience strange audio
behavior.
(You don't need to worry about the latency setting affecting the timing of your
audio recording. Your recording software adjusts for latency settings
automatically.)
So, what's best?
Every system is different, and you will need to experiment with yours in order to
find the best range of latency values. For your first few days of use, experiment
with different buffer settings.
If you are only recording signals from the MultiMix, feel free to set the latency
relatively high. This is because you will be able to monitor your audio through
the MultiMix's analog routing, which is latency-free.
If you work with software synthesizers, you will hear the latency between the
time you press a key on your keyboard and the time you hear a sound. To
minimize this latency, you will need to choose lower latencies.
MultiMix Firewire FAQ & Troubleshooting Guide Page 13