linuxaudio.org

Giso Grimm wrote:

quoted text
> Hi,

>

> On 04/07/2011 12:34 AM, Dave Phillips wrote:

>> I've been working with Ardour3 on my laptop, a machine with an AMD

>> Turion X2 CPU and an nVidia 8200M integrated video chipset. Recently I

>> started monitoring my test recordings through the headphone output of my

>> UA25 and I notice that when I move the mouse it creates scratchy sounds,

>> though QJackCtl reports no xruns and my recordings are unaffected. I

>> verified the problem with Ardour2 and Mixbus. It doesn't occur when I

>> use the integrate audio chipset (snd-hda-intel, wahoo).

>

> we observed exactly the same problem (only on the output of a custom

> made USB sound card). The noise was spikes of varying amplitude at a

> fixed rate (125ms if I remember well). Replacing the USB cable by a

> shorter one significantly reduced the problem, and it also depended on

> the USB ports used for mouse and sound card. On some mainboards/laptops

> the noise was less then on others.

Also depends on the presence or absence of an externally-powered

external USB hub. I have an external USB2 hub (having three USB ports on

laptop and 8 devices to plug into them). Running my USB soundcard

through the external hub provided large bundles of noise. Hooking it

directly to a USB port on the laptop abolished the noise. Probably bad

grounding in the external hub or its power supply.
--

David

gnome@hawaii.rr.com

authenticity, honesty, community

_______________________________________________

Linux-audio-user mailing list

Linux-audio-user@lists.linuxaudio.org

http://lists.linuxaudio.org/listinfo/linux-audio-user