M-AUDIO Quattro USB - Manual (Page 11)

In the M-Audio USB ASIO Driver control panel, to the right of the Bitwidth
section, you will see a “Latency” drop-down list that will set the Quattro’s buffer
size. A lower latency setting represents a smaller buffer size, with the lower
setting being desirable when using the ASIO drivers.
How low you will able to set the latency will depend on several factors, such as
your system’s performance and the performance of the music program itself. Try
the “Medium” setting first (which is the default, as shown in the previous
screenshot), and then try a lower setting. If your system stutters or performance
falters, try the next higher setting until the system performance stabilizes. Once
you are satisfied with any of the control panel settings, click “OK” to close the
USB Audio Quattro Settings page.
Advanced Tab
Some audio applications require more bandwidth in the USB channel for audio
than others. Native functions of other USB devices such as movements of a USB
mouse may cause clicks in the audio during playback or recording. If this occurs,
click on the “Advanced” tab and select “High”.
Note that the default setting of “Normal” will work for most applications. Setting
this to “High” should only be done if you are experiencing issues with clicks in
audio that are not associated with latency. If the “Default” setting is working,
there is no need to adjust it and is to be used only as a means of troubleshooting.
Quattro Operation on the Macintosh
The Macintosh Sound Manager
The Macintosh Sound Manager will allow you to select the USB Audio Quattro
as the system’s audio input and output device.
Open the Apple menu, then select “Sound” from the Control Panels list. The
Macintosh Sound Manager is limited to stereo input and stereo output, so only
Channels 1 and 2 are active on the Quattro under Sound Manager. The Quattro
will operate at 44.1kHz sampling rate at the 16-bit setting in this instance. At this
point in time, most music programs designed for the Mac utilize ASIO drivers.
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With any combination of three stereo pairs enabled, the Quattro will function
either as a 2x4 or a 4x2 audio device, with one input and two output pairs active
or two input and one output pair active, respectively. In this mode, the Quattro is
capable of 48kHz or 44.1kHz at either 24- or 16-bits, as set by the music
program. Note that when the 24-bit option is selected in the Quattro control
panel, the input or output stereo pair that is currently disabled will become
grayed out.
The Quattro will perform at 96kHz sampling rate with any one of the stereo pairs
enabled, and with the 24-bit Sample Depth selected. The Quattro will not operate
at 96kHz when the control panel is set to 16-bits, or when more than one stereo
pair is selected for input or output. In the following example, “Channels 1&2 In”
is enabled and 24-bit Bitwidth is selected, with the “Available Sampling Rates“
section showing 96000 Hz and 88200 Hz.
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