Ubuntu studio audio problem

[Jay Vaughan]

On Jan 17, 2010, at 9:57 PM, Tom Adam wrote:
> It was time for me to buy a new PC. So I got an Asus P7P55D Mobo with
> 4gig DDR3 memory and Intel i5 750 processor. I recovered a delta 1010
> PCI soundcard and an ATI whatever video card. Alas this is an AGP  
> card,
> and on the mobo there's no AGP slot.

for sure the delta card is going to be nice.. i think it works quite  
well in linux, no?

> So I got me a Nvidea card, alas a PCI one, not a PCIE one.

In case you haven't already: You should go ahead and install the  
NVIDEA drivers for Ubuntu on x86, I suggest.  You don't want to hack a  
3D driver do you, really?  No?  You don't need source then.  So just  
bite it and install the proprietary driver.

I am quite happy with the NVidia card in my linux box, though .. I  
have been refining control on my kernel builds pretty aggressively,  
however, not like some Linux users, perhaps.

> I've installed ubuntu studio, without any issues.

Cool .. I am settled with ubuntu studio as an audio/development rig on  
my home disk, though I do like to try out some of the USB-boot linux- 
audio specific distros from time to time.  I have puredyne, and it  
runs my system very, very well, as does 64Studio, which I don't have a  
fob for yet but will probably add soon .. :) keyboot computing is  
quite useful!

> When checking out ardour and seq 24 I ran into some issues so I opened
> QJackCtrl and opened the 'log' window. Now each time I move a  
> window, I
> get underruns.

This is a sign you have something like interrupt sharing going on in  
your video config, a driver-mishap, or some sort of poor default  
driver performance on blit operations.  You *might* get better results  
if you get the proprietary drivers installed .. did you use the  
Hardware Driver manager to see if it suggested a solution for this?   
On Ubuntu, if you have NVIDIA/ATI/OtherStrange hardware with known,  
public proprietary drivers, there is now a gui to manage their install  
and .. important .. removal.

> And when I record something, it all sounds distorted.

IRQ/Realtime stuff happening, and also maybe a kernel issue.  When you  
boot, do you get the -rt kernel option, setup and configured for audio?

Did you edit your /etc/security/limits.conf file .. you have to do  
this manually on Ubuntu Studio, after a fresh install .. see the  
Ubuntu-studio faq/google for this one.

If you didn't do this, you will get stuttering, but you may not notice  
it as well when your card is *also* producing interrupts in output.   
Note: both the rtprio setting *and* the video-card issue can be  
causing your bad results, so far, so if you fix one and not the other,  
do not panic if its not all smooth!  be sure you have fixed both a  
detected video-driver issue *and* the final rtprio tweak for ubuntu,  
together!


> I guess there's an issue with the PCI devices, soundcard and video  
> card.
> So how can I solve this? Should I just change the position of the 2
> cards?

Hardware Inventory-time .. what does lspci say your card is, and what  
is the best driver for it?  Check Hardware Driver manager in sysadmin ..

> Or should I start messing with IRQ's and such? Maybe get me a
> PCIE videocard?


There is a bit of a 'settling in' period required before you will get  
this happening, but with your hardware it should happen smoothly.  You  
have to match your motherboard with what the kernel - and some apps -  
think is happening - check your BIOS to make sure you've got 'simple  
ACPI' settings that are sensible, and disable acpi on the first few  
boots to see if things help.. It is definitely the truth that there  
are some technical steps to confirm, in your case, though ..



;
--
Jay Vaughan