Mackie Spike User Manual page 63

There are many factors that contribute to latency, and there is one in particular that you can control:
the software audio buffer size. The audio buffer (also referred to as ASIO buffer on a PC, or Core
Audio buffer on a Mac) is an area in memory that Tracktion uses to hold your audio as it works. The
buffer size is measured in samples, and usually ranges from just a few samples to thousands. The
smaller the buffer, the faster the audio gets in and out of your computer, and the lower the latency.
We would like to set this buffer as low as possible to achieve the lowest latency, but there is another
factor to consider: The smaller the buffer, the harder your computer will have to work. To illustrate
this, pretend you are given fi ve minutes to move water from a large bucket to another bucket ten feet
away. You must use either a large pint glass or a small whiskey glass to transfer the water. Which
would you chose? The pint glass of course. If you choose the whiskey glass, you would quickly grow
tired of running back and fourth moving the small amount of water. Depending on your fi tness and
speed, you may not be able to move it all in fi ve minutes. This is similar to how your computer deals
with the audio buffer. If you choose too small a buffer, the computer needs to work very hard to
quickly transfer the audio in and out of the buffer. It may not even be able to keep up, especially if
you have lots of tracks, lots of automation and/or lots of plug-ins in your work. If this happens, your
audio may stop or "drop out." Drop outs at low buffer sizes may also occur if you have a slower com-
puter or not enough memory.
For low latency and good performance from your system, it is best to adjust the buffer size to taste.
You often need to use trial and error to fi nd an acceptable buffer size. In Tracktion, this is done by
choosing the Settings tab, choosing the XD-2 in the Wave Device drop down menu, and adjusting
the Latency. Usually, a setting less than 256 samples will yield fi ne results, while a setting of 128
samples or less will be required for almost inaudible latency.
Note: While you are recording, low latency is often a priority. Mixing existing tracks on
the other hand, does not often need such extremely small settings. Many users adjust their
buffer setting between the tracking and mixing stage. Increasing the buffer size
while mixing may allow you to run a few extra plug-ins; try 1024 or 2048 samples.
User's
63
Guide