Crackling sounds with Omnistudio USB

Crackling sounds with Omnistudio USB

[Rusty Phillips]

I've done a lot to narrow this down, and I know I'm getting crackles and
pops on my Omnistudio USB from within the computer (it has zero latency
monitoring, so I can hear what happens on the device).

This only happens when recording - not playback, and I know it happens
on both my Intel 440BX motherboard (which doesn't have any problems
reported - not sure of the actual model) and my Abit KG7, which has a
Via 686B southbridge, which is reported to show such problems.

The Abit board is dual-boot, and I found a Windows USB patch from VIA
called the "USB filter patch."  This got rid of the pops and crackles
when recording in Windows.  

Anyway, anyone have any clues as to the problem or solution?



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Re: Crackling sounds with Omnistudio USB

[Lee Revell]

On Fri, 2005-01-21 at 17:19 -0500, Rusty Phillips wrote:
> I've done a lot to narrow this down, and I know I'm getting crackles and
> pops on my Omnistudio USB from within the computer (it has zero latency
> monitoring, so I can hear what happens on the device).
> 
> This only happens when recording - not playback, and I know it happens
> on both my Intel 440BX motherboard (which doesn't have any problems
> reported - not sure of the actual model) and my Abit KG7, which has a
> Via 686B southbridge, which is reported to show such problems.
> 
> The Abit board is dual-boot, and I found a Windows USB patch from VIA
> called the "USB filter patch."  This got rid of the pops and crackles
> when recording in Windows.  

Please give some more information about what the USB filter patch does.
Got a link?

What kernel are you using?

Lee



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Re: Crackling sounds with Omnistudio USB

[Rusty Phillips]

As to the version of Linux, I'm running 2.6.10 with the Alsa-CVS
drivers, and 2.4.26 with the Alsa-CVS drivers.

Unfortunately, I can't give you a link to the exact page for the USB
filter driver, but you can get to it from the VIA drivers page (just
select any Windows OS (I use 2000) and pick USB then USB 1.0 drivers)
http://www.viaarena.com/Default.aspx?PageID=2

Here's the description from the VIA page about the filter driver:

This patch fixes very specific issues under specific circumstances,
described below. Users who are unsure as to whether they should install
the patch can be assured that if they do install the patch, even if it
is not necessary, it will cause no harm to their system. The patch will
detect your systems configuration and install only when necessary. The
patch will only install on certain older VIA host controller revisions.
Under these circumstances, the patch will resolve the following issues: 

      * Fixes the issue when a connected usb hub that has no usb devices
        connected will be disabled after another usb hub is attached at
        another available root port. 
      * Fixes the issue when transferring large of amounts of data, the
        system will hang. 
      * Avoids noise from a USB audio converter or speaker. 
      * Supports a usb 1.0 add-on card. Note that this patch does not
        assist with problems concerning USB 2.0 add-on cards. 
      * Under Win2000/XP: This patch will save all register values in
        the memory before a system enters Stand By mode and then restore
        those registers when the systems resumes. This therefore avoids
        the situation where USB devices are not ready for use after a
        resume from Stand By mode. 

On Fri, 2005-01-21 at 17:44 -0500, Lee Revell wrote:
> On Fri, 2005-01-21 at 17:19 -0500, Rusty Phillips wrote:
> > I've done a lot to narrow this down, and I know I'm getting crackles and
> > pops on my Omnistudio USB from within the computer (it has zero latency
> > monitoring, so I can hear what happens on the device).
> > 
> > This only happens when recording - not playback, and I know it happens
> > on both my Intel 440BX motherboard (which doesn't have any problems
> > reported - not sure of the actual model) and my Abit KG7, which has a
> > Via 686B southbridge, which is reported to show such problems.
> > 
> > The Abit board is dual-boot, and I found a Windows USB patch from VIA
> > called the "USB filter patch."  This got rid of the pops and crackles
> > when recording in Windows.  
> 
> Please give some more information about what the USB filter patch does.
> Got a link?
> 
> What kernel are you using?
> 
> Lee
> 




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Omnistudio USB further problem report

[Rusty Phillips]

Okay, I can be even more specific with some of it's problems:
1)  The second channel of the USB device is the only channel that has
clicks and pops.  Further, it looks like its outputting a waveform, not
white noise.  It's not 60 hz, but it's pretty close to that.
2)  There are some strange initialization problems:
	If you playback on channels 1 or 2 before recording then Jack will not
do recording and playback at the same time, even though aplay and
arecord run just fine at the same time.  What happens when you try is
that you get white noise saturating the signals on all lines.
	If you record on channels 1 or 2 before playing back, then you can
never playback on 1 and 2 unless you're using jack (i.e. normal alsa
playback doesn't work anymore - all you hear is silence).  This is also
fixed by restarting the device.
3)  The S/N ratio is 10:1 on a -10dB signal.  Isn't that fantastically
bad?

Is there anything you can tell me?  Is anyone working on this?  Will
anyone be working on this?

On Fri, 2005-01-21 at 17:44 -0500, Lee Revell wrote:
> On Fri, 2005-01-21 at 17:19 -0500, Rusty Phillips wrote:
> > I've done a lot to narrow this down, and I know I'm getting crackles and
> > pops on my Omnistudio USB from within the computer (it has zero latency
> > monitoring, so I can hear what happens on the device).
> > 
> > This only happens when recording - not playback, and I know it happens
> > on both my Intel 440BX motherboard (which doesn't have any problems
> > reported - not sure of the actual model) and my Abit KG7, which has a
> > Via 686B southbridge, which is reported to show such problems.
> > 
> > The Abit board is dual-boot, and I found a Windows USB patch from VIA
> > called the "USB filter patch."  This got rid of the pops and crackles
> > when recording in Windows.  
> 
> Please give some more information about what the USB filter patch does.
> Got a link?
> 
> What kernel are you using?
> 
> Lee
> 
-- 



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Re: Omnistudio USB further problem report

[Clemens Ladisch]

Rusty Phillips wrote:
> 2)  There are some strange initialization problems:

The Omnistudio has some quirks that are similar to the Quattro ones.
I made a patch after ALSA 1.0.8, so either get the current CVS or try
to replace four files in 1.0.8 with the files in
<http://www.informatik.uni-halle.de/~ladischc/usbmidi.tar.gz>.


HTH
Clemens



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Re: Omnistudio USB further problem report

[Rusty Phillips]

Thanks for the help, but I'm afraid that doesn't change anything.  The
same problems persist.

On Fri, 2005-01-28 at 19:23 +0100, Clemens Ladisch wrote:
> Rusty Phillips wrote:
> > 2)  There are some strange initialization problems:
> 
> The Omnistudio has some quirks that are similar to the Quattro ones.
> I made a patch after ALSA 1.0.8, so either get the current CVS or try
> to replace four files in 1.0.8 with the files in
> <http://www.informatik.uni-halle.de/~ladischc/usbmidi.tar.gz>.
> 
> 
> HTH
> Clemens
> 
-- 



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