FAQ (Frequently Asked Questions)
Why does the USBPre take long to power up?
The USBPre is classified a "high power" USB peripheral. Like all
USB devices, it is required to enumerate with the operating system initially
in low power mode before it steps up to high power mode. It takes roughly 15
seconds for the USBPre to complete "checking-in" with the operating
system and be available for use.
When I plug the USBPre into the computer why do some of the input LED's
flash?
The LED's flash on enumeration with the operating system (see above). Also,
if one of the buttons is being held down on power-up, the USBPre goes into
configuration mode. This mode is used to reprogram the non-volatile memory in
the USBPre and should be avoided except when changing configuration files in
Mac OS or upgrading the USBPre.
Why can't I use Windows 95, Windows 98 (first release), or Windows NT 4.0
with the USBPre?
Windows 95 OS2 was the first Windows OS with USB support. Windows 98 (first
release) is essentially the same as Windows 95 OS2 and has an early
implementation of USB audio support. Both of these operating systems USB audio
drivers are problematic with the USBPre (and other USB audio products).
Upgrade to Windows 98SE (or Windows Me) from Windows 95 and Windows 98. In
addition, early implementations of USB hardware may not be USB 1.1 compliant
and even with Windows 98SE, interconnection with the USBPre may be
problematic.
Windows NT 4.0 has very limited USB support. Upgrade to Windows 2000 from
NT for USB audio support.
Why is the unit connected, with the power LED lit, but the input selection
LED's are not lit and I can't select the USBPre as a playback device.
The software drivers and control panel software have not been loaded on the
computer. Disconnect the USBPre and install the software from the included
CD-ROM. Also check that you are running on a system that meets the minimum
requirements.
If the computer has successfully connected to the USBPre in the past,
disconnect the hardware, wait several seconds, and reconnect. This will
reconnect the USBPre with the operating system.
I can't get the USBPre to start up. It doesn't seem to be getting enough
power.
Depending on your computer setup, you may not be connecting the USBPre to a
high-powered USB port. The USBPre requires a full 500 mA USB port like those
provided with an active hub directly on the computer. Connecting the USBPre to
a passive hub is inadequate to power the hardware, since passive hubs
typically provide 250 mA or less of current to each USB port. With iMac
computers, connect the USBPre directly to the computer, not the keyboard,
since the keyboard acts as a passive hub.
Why is audio playback low or no audio output?
The volume control in the Windows Mixer and the Mac's volume control
adjusts the output level of the PC Audio output and the level to the
headphones. The Windows mixer is accessed by the icon in the system tray that
looks like a speaker (if it is there). Alternatively, go to
Start>Programs>Entertainment>Volume Control to launch the Windows
Mixer. Raise both the "Volume Control" and the "Wave" for
more level. Verify that the USBPre is the selected playback hardware in the
Multimedia settings in the Control Panel. Raise the volume control in the Mac
for more level.
Why does the USBPre seem distorted when recording even though the red
overload LED's have not illuminated?
The headphone amplifier is most likely distorting. High monitoring levels
can overdrive the headphones when using high impedance headphones. Play back
recorded tracks at lower monitoring levels to confirm that the recorded audio
signal is distortion-free.
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 operating system and your computer's hardware/software
configuration. See USB Audio Optimization to improve performance.
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 monitoring 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 signals; any signals from
the PC stay stereo.
How do I connect a turntable to the USBPre to transfer my vinyl into my
computer?
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.
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.
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.
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.
What is an MP3 file?
MP3 is short for Moving Picture Expert Group Audio Layer 3, or MPEG Audio
Layer 3. It is a perceptual audio coding and psychoacoustic compression
algorithm that reduces the size of an audio file while minimizing the
degredation of audio quality. There are several different algorithms available to
encode into the MP3 format with the most common being the Fraunhofer encoder. There are
many programs available that play MP3 files directly and there
are a few that will record directly to MP3. (eg. MusicMatch
Jukebox). Many professional recording programs support MP3 conversion but
will not record directly into MP3. Instead the file is created as an
uncompressed PCM encoded audio file first then encoded into MP3 after
recording.
Why does the '0' LED activate before actual clipping.
The meters on the USBPre will not correspond exactly to the meters in software recording
applications. The USBPre O LED activates at ~ -1dB FS
instead of at 0 dB FS so there is some measure of safety before clipping. The
USBPre has a gain structure designed to clip the
|