[linux-audio-user] Re: [Alsa-devel] usb audio sound quality

[Patrick Shirkey]

Patrick Shirkey wrote:
> I'm getting a lot of wierd sound quality bugs while using JACK. It seems 
> like the driver is storing the crappyness somewhere and each time I 
> access it the quality gets worse. Is it possible that the driver could 
> allow the data to linger and make things unstable?
> 
> I have been doing some testing today with various softsynths and my mem 
> is getting pretty full. Turning off jack just freed up 10MB but still 
> it's at
> 
> Mem:    386484K total,   336212K used,    50272K free,    41304K buffers
> 
> The machine has been up for 7 hours. Is that reasonable?
> 
> 

This is all done with tuned disks, lowlat and root access.

Yesterday I was having this problem. I also tested the sound quality of 
native alsa vs jack by using two alsaplayers one connected to alsa and 
one connected to jack.

While doing that I found that the output quality was exactly the same so 
I assumed that it was the alsadriver that was at fault. However After 
letting the machine and device cooldown while I slept and testing with 
native alsa today the sound quality is crystal clear. When I test 
through jack the quality is degraded. I assume that it is the demands 
that jack places on the system that is causing the quality to degrade.

I have just gone down from 9 -> 6 screens in my virtual desktop and that 
seems to have gone a long way towards cleaning the sound. Any ideas on 
how I can tune x to give me those screens back? I currently use a 
geforce2 with nvidia drivers. I'm holding out on getting a new video 
card until the price of the new ATI has dropped.

Does anyone know how the support for that card is going?

-- 
Patrick Shirkey - Boost Hardware Ltd.
For the discerning hardware connoisseur
Http://www.boosthardware.com
Http://www.djcj.org - The Linux Audio Users guide
========================================

Being on stage with the band in front of crowds shouting, "Get off! No! 
We want normal music!", I think that was more like acting than anything 
I've ever done.

Goldie, 8 Nov, 2002
The Scotsman