[LAT] To much latency
jeremy at autostatic.com
Sun Oct 30 12:03:21 UTC 2011
On 10/30/2011 12:55 PM, Dave Stikkolorum wrote:
> On 30-10-11 12:25, Jeremy Jongepier wrote:
>> On 10/30/2011 12:02 PM, Dave Stikkolorum wrote:
>>> I am a musician and programmer.
>>> I use a laptop with an internal soundcard (intel)
>>> and ubuntu studo.
>>> When I see the qjack control settings window
>>> I always see a 46.6 ms latency.
>>> On a older Desktop computer with an internal ac97 soundcard
>>> or an pci sweex (cheap) I have the same problem.
>>> Reducing the sample period to 512 , reduces the latency, but
>>> always ends up with problems.
>>> My question is how to have a good studio setup
>>> for recording (and playing midi in the background)?
>>> Is it possible to better the performance with an external soundcard?
>>> What are your experiences?
>>> I also tried ccma an av linux, but the same problems.
>>> Anyone suggestions?
>>> Dave Stikkolorum
>> Hello Dave,
>> 46.4ms is the default JACK latency (1024 frames / 44100 sample rate *
>> 2 periods). You can try lowering it by reducing the number of frames.
>> But if you get xruns then (buffer errors) then you may need to
>> optimize your Ubuntu install. You might want to look here:
> I certainly will read that, thnx!
>> And it's possible to get better performance with an external
>> soundcard, especially compared to onboard cards and specifically in
>> the case of ac97 soundcards. The latter just refuse to work at lower
>> latencies (at least for me). There are quite some soundcards available
>> that yield good performance and that are compatible with Linux:
> That sounds promising.
>> For starters could you run cat /proc/asound/cards in a terminal on the
>> laptop with the Intel soundcard?
> cat /proc/asound/cards
> 0 [Intel ]: HDA-Intel - HDA Intel
> HDA Intel at 0xdb320000 irq 47
Oops, sorry, I meant cat /proc/asound/card*/codec* | grep -i codec
> How much does the processor has influence.
The lower the latency the more CPU that will consume.
> For example I have a 1,8 Ghz Pentium 4 upstairs.
That will work, I'm using JACK with a netbook which has a 1,2Ghz CPU.
But then I quickly hit the limits of what this netbook is capable of.
But I can run a simple session using my Edirol UA-25 USB soundcard with
8ms of system latency.
> I would like to use both. (one portable studio and one upstairs)
That's possible, you're best choice would be USB then assuming not all
your machines have a FireWire connection.
More information about the Linux-audio-tuning