8 Mar
2015
8 Mar
'15
3:58 a.m.
On Sat, Mar 7, 2015 at 6:13 PM, Bill White <bill.white(a)griggsinst.com>
wrote:
I apologize in advance for what seems like a trivial
and often asked
question. But I can't seem to figure out even the tools to diagnose my
problem. I've been reading web pages and alsa and jackd documentation for
two weeks, with no luck.
I'm trying to configure my ubuntu 14.04 system to use my Akai EWI USB midi
controller. I am trying to use Ted's Linux MIDI Guide
<http://tedfelix.com/linux/linux-midi.html> to configure things. But
before I get midi working I need to test that jackd can route audio to
alsa, and I can't get audio ouput from jackd.
I have verified that alsa works with pulseaudio, when pa is running. I
disabled pa and then made sure that pa did not autospawn (autospawn = no in
/etc/pulseaudio/client.conf.)
I also verified that my hardware device is hw:0. It's the only HW device
in my machine. The EWI is not currently plugged in, and it's a MIDI device
anyway.
When I run qjackctl and start the server I get this:
19:04:28.770 D-BUS: JACK server was started (org.jackaudio.service aka
jackdbus).
Sat Mar 7 19:04:28 2015: Starting jack server...
Sat Mar 7 19:04:28 2015: JACK server starting in realtime mode with
priority 10
Sat Mar 7 19:04:28 2015: Acquired audio card Audio0
Sat Mar 7 19:04:28 2015: creating alsa driver ...
hw:0|hw:0|128|2|44100|0|0|nomon|swmeter|-|32bit
JACK is using hw:0.
You should check how many channels/ports show up and compare with the
number of physical outputs on the audio chipset/back of the computer (and
maybe the front too).
With the Intel HDA in my previous machine (and ONLY that machine), the
default outputs when opened by JACK are actually channels 7&8, so to get
audio out of them, I had to move the output jack. Open the device a
different way (I can't recall the difference) and I would get 8 channels
and 1+2 went where expected.
P.P.S. The EWI works with alsa and fluidsynth alone,
but there seems to
be a noticable latency between fingering notes and hearing the notes. I'm
hoping jack will fix some or all of that.
JACK can't reduce latency. It just tends toward lower latency by default.