I use my system as my stereo. It's the only thing I listen to. For quite some time now though, I have had a problem with audio not being properly played. What I get is what sounds like reverberation in the audio feed. I found that increasing the amount of time for the feeds to be buffered helps, but only partially.

I also installed another parallel system in this very same computer (on a different disk) which initially didn't have this problem. But then I did an upgrade and the problem became apparent on that system also. However after having done a couple of reboots, I noticed the problem disappeared. Now that system running is running clean as it was initially.

This may be an issue with my nVidia drivers. I'm not sure. Because I noticed problems on the second parallel system after attempting to install the proprietary nVidia graphics driver, which had numerous unpleasant side effects. So I removed it. But the problem didn't go away immediately. Only after I had rebooted a number of times did the sound begin to play as it would normally be expected to.

My primary system, the one from which I am now posting this runs KDE. But on the parallel system, due to a much smaller disk space, I am running XFCE. So this isn't a KDE-only issue.

I would prefer to have a solution which eliminates this problem altogether, and an explanation for why it happens in the first place. So if there is someone who has direct knowledge of this issue, please inform me.

Thank you!
Xavian-Anderson Macpherson
Shingoshi

From the description it's hard to say what it is, but it might be a hardware issue.

Possible causes:

0) Do you have a mic attached ? Mute all mics and mic boost in alsamixer.
1) Speakers ... can you test others ? I had some Bose ones that had all sorts of strange things.
2) Is your sound card on the mobo or PCI ? do you have any others to test ?
3) PSU, is it old ? Is its power output close to the limit for the system ? Have you had sudden crashes ?

Does it stutter any or is it just reverberation ?

Stuttering and reverberation are the two sound effects I'm experiencing here. Reverberation was the closest I could think of at the time to most closely define the problem. But what sounds like stuttering is also apparent.

0) I have no mics attached to this system. But I will remove the settings for them in the sound card with AlsaMixer.
1) I don't think this is related in anyway to the speakers. As I've already said the system worked before without issue with the same speakers I have now. Secondly, the parallel installation works as expected with the same speakers.
2) My sound card is integrated on the motherboard. It wouldn't be a motherboard issue, since the motherboard has delivered proper performance with this installation in the past, and continues to with the parallel system.
3) My powersupply is brand new. It came with this Antec chassis. This system is extremely stable, running 24/7 for months at a time without ever being shutdown. Only rebooting for new kernel upgrades.

Hope that answers your questions.

Xavian-Anderson Macpherson
Shingoshi

Hmm, ok, so this happens on two different HDDs, right ? What filesystems are each using, what I/O scheduler, what distros ?

I've had stuttering problems in the past using a certain combo of filesystem and I/O scheduler (JFS + CFQ = bad), the only way to fix it was change I/O scheduler, which fixed it. If buffering helps it, then it could have something to do with the HDD and/or filesystem.

I only use the SGI XFS filesystem on everything that I run. On both of these systems (1+2), the filesystem has never changed. And on both, they have worked properly in the past. Although system #2 continues to function now without any errors. And this is NOT a disk issue either. I have not changed my disks. And this problem occurred on the second system using a different disk, and then disappeared. No more problem there.

I don't know about the scheduler for XFS (driver). If it has been changed, I'm not aware of it. But it has never been a problem in the past. Although it's an interesting point of consideration. But that would point to a change in the configuration by the developer during the build process. So whoever built the XFS driver for Slackware64-current may be the only one who knows.

Xavian-Anderson Macpherson
Shingoshi

I keep having the situation where the buffer is emptied and must be reloaded before the station continues playing. So the delivery of the feed is intermittent.

Xavian-Anderson Macpherson
Shingoshi

I think it might be the I/O scheduler, possibly, run:

The one in brackets is the active one. You can change it by echoing the name of the scheduler you want into that file. Remember to use the right device node instead of 'sda'.

It can have a huge impact especially on playing audio, so try it out.

I'm running my system with my / mounted on RAID1. So my device should be /dev/md0. I think that if I wrote to either /dev/sda or /dev/sdb, I would wind up with a corrupt filesystem. So what exactly am I supposed to do? Since it is quite unlikely the information exists in a specific man page or how-to. I would need to change the i/o scheduler for the RAID1 partition, not the individual drives.

bash-4.1$ cat /sys/block/md/queue/scheduler
cat: /sys/block/md/queue/scheduler: No such file or directory
I get the same result for md0.

Xavian-Anderson Macpherson
Shingoshi

Hmm, well you didn't mention your system setup, I haven't dealt much with RAID. I assume this is software RAID with 2 HDDs, right ?

The IO scheduler can only be set per device, so you can't set it for the whole RAID array at once. I don't know if it is dangerous to set it for the drives if they are in a RAID array, I have never tried it.

On a different note if you search google you'll see that indeed nvidia drivers can cause audio stuttering, so you may wanna mess with different versions of the drivers if you need them, there's nothing else anyone here can do if that is the cause, post on the nvidia forums for that.

There's only the Slackware kernel drivers installed on my system. So whatever came shipped with the kernel is what would be causing this. I don't know what kind of support nVidia forums would offer for Linux drivers provided through Slackware.

Xavian-Anderson Macpherson
Shingoshi

Well, if you don't have the proprietary nvidia drivers installed, then it can't be that, but you said earlier that they caused it. Slackware doesn't come with the nvidia driver installed, it's not legal to distribute it with a distro anyway.

I just checked my XMMS settings. Specifically I checked to see which plugins I had enabled. Turns out I had one for ECHO effects turned on. That may have solved this. But it still doesn't make sense. Because I still hear it to a certain extent. And I've always had better playback with the station (SmoothJazz.com) I have on now as opposed to the one (SwissGrove.ch) I normally listen to.

Oh crap. Now I definitely hear the same effect. I just tried reverting back to my primary station, but can't seem to get it to come up. But that's happened in the past do to loads. So I'll have to wait to verify what the final result is. But it seems like the situation remains as before.

Xavian-Anderson Macpherson
Shingoshi

I was using the nvidiafb and vesafb at different times. It was only after I built and installed the proprietary driver on the second installation that I encountered problems. When I removed it the problem went away a short while later.

But the original problem still exists as described. Though I can't tell how much if any better the conditions are using my backup station.

Xavian-Anderson Macpherson
Shingoshi

Seems your output is redirected to your input line, which is redirected to your output, etc...
Alsamixer, then F5 to see in/out ports and play around with capture/inputs.

Edit : Also, 2.6.33 hda module is broken on certain platforms, including nvidia.