26 Feb
2015
26 Feb
'15
5:18 p.m.
Hei.
I am running linux on a Debian machine with kx repositories, connected
to a Mackie Onyx 1640-i.
Linux kx 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt4-3 (2015-02-03) x86_64
GNU/Linux
04:00.0 FireWire (IEEE 1394): Texas Instruments TSB43AB23
IEEE-1394a-2000 Controller (PHY/Link)
When i record multitrack audio using Ardour and jackd, i see that the
sample frequency is set to 44100.
The audio files are also at 44100, according to file:
root@kx:/home/humla/akt3bolger/interchange/akt3bolger/audiofiles# file
bass-2.wav
<head> bass-2.wav: RIFF (little-endian) data, WAVE audio, mono 44100 Hz
After doing a mix of the material on a separate machine using Ardour3 at
44100, and dumping the mix internally to a 44100 WAV, i received a mail
from the band in which they tell me that the mix is faster and at a
higher pitch than the audio they recorded through a video camera at the
concert.
When i playback audio from the linux machine (like mp3s ) through the
firewire and the Onyx console, i get random switches of speed and pitch.
I have been working in professional audio, and i know there must be a
problem with the sample frequency lock and synch between the two
devices, so that one is on the wrong sample frequency, and "translates"
the bitstream wrongly. Normally in a digital audio chain you have a
machine that is "master" and one that is "slave".
The problem here is that the console has no display showing the sample
frequency it is locked at, and the Linux machine does not show any
master / slave feature in jack or ardour.
There is something strange going on here.
The machine has also another analog audio card:
00:1b.0 Audio device: Intel Corporation 82801H (ICH8 Family) HD Audio
Controller (rev 02)
And i don't know how this could influence the setup.