26 Jul
2014
26 Jul
'14
8:44 p.m.
On 07/26/2014 07:42 PM, Ken Restivo wrote:
I was playing around with trying to use a Pi as a
synth.
So far so good except for two problems:
1) I've run into this:
http://comments.gmane.org/gmane.comp.audio.jackit/26263
But I'm already using
jackd2_1.9.8~dfsg.4+20120529git007cdc37-5+fixed1~raspbian1_armhf.deb
which supposedly has Dbus removed/excised/banished/purged/kicked-to-the-curb.
And yet, no dice, same error. Haven't had time to investigate it yet.
I went back to jackd1 (wow, it's like it's 2007 all over again).
Hello Ken,
What does 'apt-cache policy jackd2' say? It seems like you were not
using my package. Jack1 might be a better choice on the RPi anyway as it
has a slightly smaller memory footprint. And yes, this matters on the
RPi since it has only 512M RAM.
2) The sound coming out of either the built-in audio or an external C-Media USB
interface
is cracking and nasty, with obvious aliasing distortion. Any ideas why? I've
tried
44.1k and 48k. No xruns tho, which is nice, at 44100/512/3 using jackd1 and
fluidsynth.
I've used it with a C-Media USB interface too and it worked without
crackling. Is there anything else connected to the USB ports? Are you
running the RPi with or without X? Probably without otherwise you
wouldn't run into the D-Bus issue. What kind of power adapter are you
using? Fluidsynth shouldn't be an issue, did you also try other apps
like amsynth? Do you also get crackling then?
I've got it overclocked to 1Ghz, all is well with
that (ran the self-test), and
using the performance guv'na.
I'm not going higher than 950Mhz, I got a lot of SD corruption issues
when trying to go higher than that.
I haven't tried with my FastTrack Pro yet because
the Pi can't power it at the
same time as a MIDI keyboard, and a working power cube for the keyboard has gone
missing.
Did you try backfeeding the RPi via a powered USB hub?
The crackling/aliased sound is the big stumbling block
though. Any ideas?
-ken
Jeremy