Xitel MD-PORT AN1 User Manual - page 6
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3. My AN1 fails to set itself as preferred audio device automatically
Problem: When you plug in the AN1, it is not automatically being configured as preferred audio device.
Fix: This occurs if a system’s soundcard is ISA based – common for standard on board audio solutions (since
Windows cannot automatically take a setting away from an ISA soundcard and give it to the AN1). It will also
occur if you are running an audio program when you plug in or unplug the AN1. Make sure to therefore close
all audio programs before doing this. You may need to configure your computer manually by selecting USB
Audio Device in the Multimedia Control Panel or the Sounds and Multimedia Properties control panel. See
the section "Checking that the AN1 is selected as preferred device in Windows 98, Windows ME, and
Windows 2000" earlier in this manual for further details.
4. My AN1 seems to be introducing pops and clicks
Problem: You’ve installed the AN1 and it seems to be recording fine, except there are pops and clicks every
now and then.
Fix: Some USB host controllers do not function within USB specification. Also Windows, in conjunction with
other hardware in your system, may be consuming all the isochronous bandwidth of the USB bus. Both of
these interfere with the data flowing to the AN1, causing it to randomly add pops and clicks. The main
instances where this occurs is if:
•
USB frame rates are out of specification - isochronous data transfer (required for audio) is not possible
via USB with a frame rate that is too fast or too slow.
•
Controllers do not enumerate devices correctly - some controllers do not send USB resets at the
appropriate times or may enumerate one part of a composite device.
•
Corrupting audio data - some USB controllers introduce artifacts into sound data (i.e. CATC traces of USB
data have shown non-zero vales in data that should be all zeros).
To solve this problem, make sure you are not running any other programs in the background when trying to
record with the AN1 - anything that causes a lot of hard disk access can effect the data flowing down the
USB bus. Virus checking programs that continually run in the background are particular bad. Some drastically
effect the isochronous data flow down the USB bus and starve the AN1 of data. It is therefore important to
disable all virus checking programs. Also, make sure that you are running the most up to date drivers for your
graphics cards and modems. If you are on a network, it is advisable to log off.
Note: If you are using a laptop or notebook computer, the data flowing to the AN1 can be severely effected by
the processing power management of the CPU. Ensure that in the System control panel your computer is set
to Desktop. To verify this, go to Start, then Settings, then Control Panel. Click on System and go to the
Performance Tab. In Performance, click on File System and make sure your laptop is set to Desktop and not
Server. Some laptops are not suitable for the decoding and recording of MP3 via USB due to the variable
operating speed of their CPU and other power management features. Check with your laptop manufacturer to
ensure that the USB environment on your system supports USB audio applications.
Further information on all of these topics is available on our website at www.xitel.com.
MD-PORT
TM
AN1
MAC USERS MANUAL
(PC users: please turn to page 2)
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