UA-4FX advanced mode noise

jborden

I've recently purchased an Edirol UA-4FX usb sound mixer, which is supported in a "standard" usb sound device mode which supports 16bit at 44.1Khz., and an "advanced" mode which allows up to 24bit at 96Khz as well as enabling use of the onboard midi ports. Alsa supports both the standard and advanced modes on this device, however, when I am in advanced mode, I am getting some extra background noise which is especially noticable at lower volumes and certain frequencies. I have attached a tar file containing two mp3s comparing the output of the standard and advanced modes. I've tried linux kernels 2.6.28, 2.6.29, and the git sources alsa code all with the same results. Is anyone else with this device having a similar issue?

Note: the file was too big to attach, so here's some urls for each:

Standard:

http://209.90.109.2/test-standard-mode.wav.mp3

Advanced:

http://209.90.109.2/test-advanced-mode.wav.mp3

atreyu

jborden wrote:

I've recently purchased an Edirol UA-4FX usb sound mixer, which is supported in a "standard" usb sound device mode which supports 16bit at 44.1Khz., and an "advanced" mode which allows up to 24bit at 96Khz as well as enabling use of the onboard midi ports. Alsa supports both the standard and advanced modes on this device, however, when I am in advanced mode, I am getting some extra background noise which is especially noticable at lower volumes and certain frequencies. I have attached a tar file containing two mp3s comparing the output of the standard and advanced modes. I've tried linux kernels 2.6.28, 2.6.29, and the git sources alsa code all with the same results. Is anyone else with this device having a similar issue?

Note: the file was too big to attach, so here's some urls for each:

Standard:
http://209.90.109.2/test-standard-mode.wav.mp3

Advanced:
http://209.90.109.2/test-advanced-mode.wav.mp3

I assume you've already run alsamixer and futzed with the volume levels there? I've seen some background noise get introduced when my Line-In and Mic levels were too high...

jborden

I assume you've already run alsamixer and futzed with the volume levels there? I've seen some background noise get introduced when my Line-In and Mic levels were too high...

On this particular device there isn't a software mixing control. All volume control is done using mixing knobs on the device itself, but yes, adjusting those controls does not make a difference on the noise produced during playback. The volume knobs merely make all audio louder or softer, including the noise.

woboyle

It's possible that the noise is hardware related, perhaps due to external interference? The wiring is especially conducive to inducted spikes in the signal. Make sure that all cables and wires are kept a reasonable distance from power cables, wireless devices, and network cables.

jborden

It's possible that the noise is hardware related, perhaps due to external interference? The wiring is especially conducive to inducted spikes in the signal. Make sure that all cables and wires are kept a reasonable distance from power cables, wireless devices, and network cables.

In this case I don't believe that to be the issue. My reasons are that first, no noise in standard mode and second, no noise in advanced mode in that other OS.

jborden

In answer my own question: according to some recent wiki posts, others with this device are having a similar issue. It seems that more reverse engineering is required to fix the problem.

kaori

Just bought the UA-4FX and was trying to get it working in advance mode
on a fedora 11 box. I had the same problem getting hiss noise like
nose given by a fm radio tuned to off station while playing a sound
even though the kernel recognizes the UA-4FX as usb sound device.

I was finally able to get it working. What I did was I updated the
pulseaudio to 0.9.15-14 which is the latest verion. On the fedora 11,
it can be done by yum update.

While trouble shooting, I found out that the pulseaudio installed in
the fedra 11 was unable to transfer sounds to the UA-4FX in format
24bit/44k, 48k or 96 since it had the bugs unable to handle 24bit
format. As the result of the bug, the pulseaudio transfers sound in
standard format 16bit/44k even though advance mode of UA-4FX requires
24bit/44k, 48k or 96. Miss matching sound format caused noise.

Also the alsa wiki page suggests the patch for UA-4FX but it was
already integrated to the kernel 2.26.8. As fedora 11 has the kernel
2.26.9 installed, I did not need to patch the kernel.

woboyle

What exactly do you mean by "background noise"? Is this noise from your environment, or is it electronic noise from interference and such? If interference/electronic noise, then you probably want to check on cable routing and shielding, proximity to wireless devices (wifi, bluetooth, cellphones) or speakers, etc. If environmental, then try noise-canceling microphones.