[LAU] midi keyboards, jackd, low latency

tizo tizone at gmail.com
Fri Feb 27 10:02:39 EST 2009

On Thu, Feb 26, 2009 at 9:21 PM, Paul Davis <paul at linuxaudiosystems.com> wrote:
> On Thu, Feb 26, 2009 at 4:20 PM, tizo <tizone at gmail.com> wrote:
>> Hi there,
>> Sorry about my previous mail. I was just starting to write a draft
>> about the topics I want to ask, and I accidentally push the send
>> button.
>> Well, my goal is to play two midi keyboards, sending the events
>> through jackd, to qsynth. My computer is a Laptop HP 550, with HDA
>> Intel sound card, 3 GB of memory, and a Core 2 DUO CPU of 1.40 GHz. My
>> OS is UbuntuStudio 8.04, with kernel 2.6.24-23-rt.
>> First of all, I cannot run jackd without xruns, if I configure it with
>> 32 frames per period, or less. I am running it as root, with realtime,
>> and a priority of 70. As soon as I run it, it starts to count xruns,
>> and I am only executing jackd.
> 32 frames per interrupt is VERY ambitious with an Intel HDA chipset. Its not
> impossible but every single part of your system has to be "just right" for
> this to work. I would start with a less ambitious goal first, and get some
> experience with the setup before trying to get all the way to this latency
> level.
> moving to USB will likely make things worse. latencies like this are best
> accomplished with good, prosumer level PCI audio interfaces.
> --p

Ok. As I said in another email, I have to make more serious tests with
both midi keyboards, but I think that I could play right with 64 or
128 frames (with some xruns).

Anyway, I am thinking in buy a new desktop PC, and use it with my old
Sound Blaster Live. I guess that I could do much more things with that
configuration, not just play. How about the performance of that card?.

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