[LAT] To much latency

Rafael Vega email.rafa at gmail.com
Tue Nov 1 00:25:13 UTC 2011

Hello Everyone,

I'm having a similar problem so I'll take the liberty to jump into this 
thread, let me know if I should create a new thread instead.

My laptop is a MacBookPro8,1 with i7 processor, 8GB ram, built-in intel 
HDA soundcard, dual boot setup with mac os + jack + ardour and 64 bit 
Ubuntu Studio 11.04 + jack + ardour + QTractor.

On MacOS, jack works really well with the default settings: 
/usr/local/bin/jackd -R -d coreaudio -p 64 -r 44100 -i 2 -o 2 -C 
AppleHDAEngineInput:1B,0,1,0:1 -P AppleHDAEngineOutput:1B,0,1,1:0

But on Ubuntu, the only way I can get sound that sounds clear (no 
distortion or clicks) is by setting the "force 16 bit" flag and 4096 
frames. I tried some of the troubleshooting guides out there and 
compiled the latest version of ALSA but the result was the same. I also 
tried AVLinux which comes with a preemptive kernel but still the same :(

Also, If I use ALSA directly on an application that supports it 
(pd-extended for example) the latency feels a lot shorter than using 
jack with the settings I described (I havent measured it, don't know how).

If it helps, here's the output of cat /proc/asound/card*/codec* | grep 
-i codec

Codec: Cirrus Logic CS4206
Codec: Intel CougarPoint HDMI

Has anyone successfully setup this kind of sound card on Linux + Jack? 
Any tips on setting up jack?



On 10/31/2011 06:58 AM, Jeremy Jongepier wrote:
> On 10/30/2011 03:39 PM, Dave Stikkolorum wrote:
>> Ok, you use the realtime option also?
> Yes, and if you set the realtime option ame sure to enter a value for 
> the JACK's priority also. Default is 10 which is a bit low on a scale 
> of 100. Also make sure you have set up JACK to use realtime priorities.
> Best,
> Jeremy
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> Linux-audio-tuning at lists.linuxaudio.org
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