lördag 17 januari 2009

Hydrogen drum kits, audio latency, jack crashing

I've been recording a bit in Ubuntu 8.04 (Hardy) using Ardour and Hydrogen, a splendid drum machine / sequencer. The audio interface is, as I have mentioned, an Edirol FA-66.

Hydrogen drum kits
It's been a while since I last checked the list of Hydrogen drum kits, so I was pleased to see that there are more than the few I knew of. You can find them here:

Officially distributed drumkits
A blog post with a bunch of different kits
Asma Davul, a turkish drum

The blog post above actually links to a drum kit I made called Aqoustic. It was a first attempt, using samples of a friend's drums. Not very high quality. The blogger calls it "another homemade jobby". Urban Dictionary tells me "jobby" is scottish for poo. Fair enough!

Audio latency
I have been using jack in real time mode with a buffer size of 512kb.

One thing I've noticed that's different from when I recorded with a mere SoundBlaster Live card on my desktop computer is that the latency between different programs seems to be gone. When syncinc Ardour and Hydrogen for recording drums, I don't have to trim the resulting audio region, which I needed to do before because of the lag.

When recording from an external source - in this case: electric guitar through a Boss ME-50 - the latency varies. Sometimes I seem to get minimal latency, again with no need to trim the recorded audio. Curiously, when I turn up the monitor mix knob on the FA-66 to hear what I play while I record, there is a noticeable latency.

Jack server crashing
After a while of doing takes on several tracks, the jack server crashed. Not with a bang, but with a whimper. Qjackctl froze and Ardour reported that the connection to jack was lost. When trying to restart it, I got an error message (which I will paste here later). This latter error was resolved by resetting the firewire bus using a program called gscanbus and then starting jack. However, it didn't take long before jack crashed again. I will have to find out what causes this problem. I have yet to try different buffer settings, maybe that will give me something.

I hope it's not a hardware issue. I have decided to buy the FA-66, although I haven't been able to test it first as much as I had hoped to. I have done little recording with Ableton Live in Windows, and I didn't notice any anomalies then. This should mean that my problems in Linux are solvable.

3 kommentarer:

  1. Curious, are you using stock jack + freebob, or are you using jack 0.116.1 + ffado from my ppa?

    SvaraRadera
  2. I'm using stock jack + freebob. If by "my ppa" you mean the links you gave me earlier, I haven't used them as I'm still on a 32 bit system.

    I'd thought I'd try building ffado soon though. Do I need to re-compile the kernel with it, or is it enough to compile the module itself?

    SvaraRadera
  3. No need to rebuild the kernel.

    With "my ppa", I actually meant https://launchpad.net/~khashayar/+archive/ppa. Mind you, if you just add that PPA to your sources.list, it will upgrade a lot of packages, including alsa libs, jack, ffado and so on. So be careful if you use anything from there. Feel free to email me if you have problems with anything from the PPA (khashayar dot lists at gmail dot com).

    SvaraRadera