amd64 Gentoo tips - was [ardour-users] Dolby Digital Sound Mixing

Allan Klinbail allan_k at
Sat Aug 20 20:44:48 PDT 2005

On Sun, 2005-08-14 at 19:21 +0200, Edwin Peer wrote:
> On Sunday 14 August 2005 17:18, Allan Klinbail wrote:
> > Hi, I'm using a 64-bit AMD system (Gentoo). The only thing I can't get
> > working are the VST libraries.... (through any of the three available
> > options).... otherwise my system is very stable and working  at low
> > latency ... (2.9 ms in 44.k 32 bit mode with 16+ tracks and multiple
> > plugins). My only recommendation is  use Gentoo if you can and optimize
> > as much as you can.
> I would love to know more about your setup. I am also running an amd64 system 
> under Gentoo and mostly it works. I am using two RME Multiface boards to get 
> 16 tracks of analogue inputs but jack suffers horrible xruns if I actually 
> try to get ALSA to map both both cards into one virtual card for jack. The 
> solution I've come up with at the moment is sending the analogue inputs of 
> the one card via ADAT to the other card and only speaking to the first card 
> with ALSA. Not ideal, but for now it's okay. I may want to use the other 
> inputs later tho'.

I'm not sure if having both as one virtual card is the best way to go,
unless they are designed to do that they might not sync properly.... I'm
using an M_Audio Delta 66 card. I can't track in more than 4 tracks at a
time.. due to my setup... it would be nice to have more but not

> Are you running Ingo's low latency kernel? I haven't managed to get it to run 
> stable - when I even get a version of it to actually compile under amd64. 
> Using the standard gentoo-sources, I haven't been able to get down to 2.9ms 
> reliably on fairly meaty hardware (Dell PE1800, dual EM64T, SCSI RAID-5 w/5x 
> 10 000RPM drives). 

I'm using the "Nitro" sources. I am currently on 2.6.12-nitro5 which is
the lastest version. They are from a custom ebuild, but you can find
everything you need from the Gentoo Forums (just type in
nitro-sources)These sources have ..  I have had substantially better
results that the standard gentoo kernels.. I'm using Reiser4 on my
recording partitions and it seems to be quicker, but has a bigger CPU

> Other weird issues I have are:
> 1) Ardour (beta29, haven't ventured into ardour-cvs yet) sometimes crashes. I 
> haven't reported any of these problems yet, because I have not been able to 
> reproduce them reliably.
Other than disconnects from Jack, ardour doesn't really crash for me..

> 2) Jamin (portage, 0.9.0-r1) sometimes fails to start but works properly once 
> it does and 0.95.0-r6 causes horrible crackle with lots of xruns.  

Interesting I haven't had any problems with Jamin 0.95... I can run
multiple instances simultaneously. Although I use simpler systems for
EQ'ing (i.e. parametric with shelves) and leave Jamin just for

Sound like you have a lot of CPU load.. or maybe other stuff going on...
also what Window Manager are you using? I use fluxbox, and recommend it
or any other "box" WM, over KDE or Gnome.... 

> 3)  Not ardour related, but Rezound dies on playback (This particular issue 
> has already been reported on Rezound's bug tracker for amd64, so at least I 
> know I'm not the only one).

No using rezound.. so I couldn't say. 

Gotta go .. got a band practice... 

> - Edwin
Allan Klinbail <allan_k at>

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