8. Why does my audio click?
There are a variety of reasons that audio may
have dropouts, or gaps during playback or
recording. This is primarily an issue between
the USB audio implementation of the operat-
ing system and your computer’s hardware
and software configuration. See USB Audio
Optimization to improve performance.
9. Why the mono/stereo button? Does it
mono the inputs?
The ability to monitor in mono is important
when multi-track recording. When recording
with one input, the ability to hear that input
in both ears in the headphones makes moni-
toring less fatiguing. Monitoring in mono is
necessary with single channel sources. The
Mono function can be heard only through the
headphones, and only affects the input sig-
nals; any signals from the PC stay stereo.
10. How do I connect a turntable to the
USBPre to transfer my vinyl into my com-
puter?
The output of a turntable is a low-level, high
impedance signal. A phono preamplifier is
needed between the turntable and the Tape
input of the USBPre to amplify and equalize
the turntable signal.
11. How do I get my internal CD player to play
through the USBPre?
In Windows 98, go to
Start>Settings>Control Panel>Multimedia
and select the CD Music tab and check
the “Enable digital CD audio” to play audio
through the USBPre. In Windows 2000, go to
Start>Settings>Control Panel>Sounds and
Multimedia
> and select the Hardware tab.
Select the CD-ROM, and then click on the
Properties button, then select the Properties
tab, and check the “Enable digital CD audio…
”. In Mac OS, select USB Audio as the output
type in the Sound Control Panel.
12. When playing audio through the unit the
meters don’t respond. Why?
The front panel meters of the USBPre are
analog input meters only. No output levels
show on them. In addition the meters are
measuring analog inputs only, therefore they
will not respond with an S/PDIF input signal.
13. I am losing the first few seconds of audio
when I use the S/PDIF output in Windows.
Why?
With S/PDIF interconnections a clock signal
is sent along with the audio data. Depending
on the receiving input, it may take several
seconds for the S/PDIF input to “lock” onto
the received clock. To minimize this lock-up
time the USBPre Control Panel has an output
sample rate sync frequency selection (see S/
PDIF in the Windows OS section). If selected
the S/PDIF output transmits a blank signal at
the selected frequency. By sending an empty
signal but at a valid clock rate external S/
PDIF inputs can immediately lock to the audio
data when present.
User Guide and
Technical Information
page 24
SOUND DEVICES, LLC
