linuxaudio.org

On 10/30/2011 12:55 PM, Dave Stikkolorum wrote:

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>

>

> On 30-10-11 12:25, Jeremy Jongepier wrote:

>> On 10/30/2011 12:02 PM, Dave Stikkolorum wrote:

>>> Hi,

>>>

>>> 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?

>>>

>>> Regards,

>>>

>>> 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:

>> http://wiki.linuxmusicians.com/doku.php?id=system_configuration

> 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:

>> http://wiki.linuxaudio.org/wiki/current_audio_gear

>>

> 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

But thanks!
> How much does the processor has influence.

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>

The lower the latency the more CPU that will consume.
> For example I have a 1,8 Ghz Pentium 4 upstairs.

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>

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)

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>

That's possible, you're best choice would be USB then assuming not all

your machines have a FireWire connection.
Best,
Jeremy
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