1. Purchase a PCI based USB card (desktops) or PCMCIA USB card (laptops). These cards often solve the problem of white noise because the USB implementation on these cards overrides the USB built into your computer. For more information on PCI Cards please visit PCI CARD
2. Adjust the Buffer size in your Line 6 product Driver Console which can be located in your Control Panel (PC's).
Start/Programs/Line 6/Tools/Line 6 Audio-MIDI Devices
The newest version of the driver console will display a Buffer Size slider that you can adjust towards EXTRA SMALL, MEDIUM, or LARGE. Please first move this slider to MEDIUM or LARGE to see if this helps. With the old driver console, you'll see that your latency is defaulted at 2, the lower the latency settings the more CPU usage the software is taking up. Start by backing up your buffer to 20 and work your way down to the lowest setting you can get to before the white noise or static resurfaces. Your objective is to have little or no latency while eliminating that white noise. For Mac users you can find your buffer settings in the recording software you are using usually under your preferences menu.
3.Laptop people this is for you. Change the Power Schemes on your computer (PC's only). To change the Power Schemes in Start/Control Panel/Power Options/ within the power options menu change power schemes to "Always On". Also, underneath the Power Schemes, please make sure that turn off hard disks, system hibernate and system standby are all set to "never".
4. USB hubs can also cause white noise or audio interrupts. If you are using a USB hub and experiencing this, please disconnect the hub and plug your cable directly into a USB port on your computer. This problem especially occurs with Mac users. Make sure you are connecting directly to your computer and not your keyboard as this acts essentially like a USB hub.
5. On some CPU configurations, actively using wireless networking/connectivity while streaming (recording/playing)computer audio via Line 6 USB devices can sometimes impact the fidelity of the audio streams (e.g. noise or artifacts are heard in the audio while using wireless connectivity). For best results, do not use or disable wireless connectivity while recording and playing audio-over-USB.
6. Remember to disable wireless networking devices. A known issue for Mac OSX 10.4.11 users as of May 2008 was an update from Apple that causes audio glitching and stuttering effects during ANY audio playback with USB interfaces if Airport Wireless Networking is enabled. The solution is to disable the device during Audio runtime of USB related interface units.
