Path: number1.nntp.dca.giganews.com!border1.nntp.dca.giganews.co
!nntp.giganews.com!wns14feed!worldnet.att.net!128.230.129.106!ne
s.maxwell.syr.edu!sn-xt-sjc-05!sn-xt-sjc-11!sn-xt-sjc-09!sn-post
sjc-01!supernews.com!news.supernews.com!not-for-mail
From: arachnid
Newsgroups: alt.os.linux.ubuntu
Subject: Re: ubuntu MIDI questions
Date: Fri, 09 Feb 2007 18:50:04 -0600
Organization: Posted via Supernews, http://www.supernews.com
Message-Id:
User-Agent: Pan/0.14.2.91 (As She Crawled Across the Table (Debian GNU/Linux))
References:
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 8bit
X-Complaints-To: abuse@supernews.com
Lines: 135
Xref: number1.nntp.dca.giganews.com alt.os.linux.ubuntu:10066
On Fri, 09 Feb 2007 15:08:12 +0000, Franz Fripplfrappl wrote:
> Ubuntu 6.1 Edgy here.
>
> I have a Korg SB-250 keyboard and I wish to connect it via MIDI to
> Rosegarden.
>
> The motherboard is an Asus A7N8X with onboard sound.
>
> What do I need to do to make the connection work?
>
> Can I connect the keyboard via USB?
I'm not familiar with the Korg but I have an M-Audio Axiom with built-in
midi-to-USB converter. It works fine with USB. I know there are
midi-to-USB converters that work well with Linux but don't know the models
offhand. If you need one, there are a few users in comp.music.midi or
alt.music.midi who also run Linux who might recommend specific brands. A
little googling can also turn up numerous discussions of
MIDI->USB converters under Linux.
Here are some pages dealing with MIDI on the Ubuntu site:
https://help.ubuntu.com/community/UbuntuStudioPreparation
https://help.ubuntu.com/community/HowToJACKConfiguration
However these try to have you do too much at once and IMO are more
confusing than helpful. Also if you have a fast enough motherboard, you
probably don't need to go to all the hassle of building a real-time
kernel like they advise. I do OK with a 2.2 Ghz CPU.
There's an easier way to start that involves only installing and
configuring three applications. That'll get you up to the point where your
keyboard can make sounds. But first, if you have a speed-stepping CPU, you
need to disable the speed-stepping or it will cause all sorts of odd MIDI
problems. I don't know about other systems, but, on mine I disable
speed-stepping by killing the powernowd daemon:
sudo killall powernowd
This causes the CPU to zoom to maximum speed and stay there. I have no
idea if this is bad for CPU's but mine hasn't melted down (yet). You'll
need to repeat this every time you boot. You can disable the powernowd
daemon for good using System->Administration->Boot-up Manager. Look for
"Controls CPU Speed and Voltage to save Power" and underneath that in
small letters, "powernowd". Uncheck the box, close it, reboot. If you're
running a laptop this will have the side-effect of increasing power
consumption which is why I prefer to disable powernowd only when I need to
do MIDI stuff.
[If you don't already have something set up, you can monitor CPU speed
using the CPU Frequency Scaling Monitor. Right-click the taskbar to the
left of your icon tray, select "Add to Panel", look under
"System&Hardware", and you should see it. Once you've added it, it will
display the current CPU speed]
Now here's a gentler MIDI setup than UbuntuStudioPreparation. This is off
the top of my head, so just say something here if it doesn't work and I'll
figure out what I got wrong:
Start by installing just three programs - jack, jackctl, and zynaddsubfx.
zynaddsubfx can display its own on-screen keyboard. The plan is to use
this to make sure everything else is set up and working before plugging
the Korg in. That way if the Korg doesn't work, you'll know the problem
isn't in your MIDI setup.
JACK is a patch panel and is used to connect and route MIDI and audio
inputs and ouputs. JACK can be controlled from the command line but in a
GUI you access it through jackctl. For new we need to use it to connect
the output of zynaddsubfx to your soundcard inputs.
So, run Applications->Sound&Video->JACK Control. If it doesn't start with
the dialog on-screen, just click the red icon that appears in the icon
tray. Click on setup and follow the instructions on the above
HowToJACKConfiguration page to configure it (but ignore the side trip to
the UbuntuStudioPreparation page). Click on "Messages" so you can keep an
eye on messages, and then click on "connect" and note the connections
window. Ignore xruns for now - they're common when nothing is connected.
Now start up Applications->Sound&Video->zynaddsubfx. If it asks you which
mode to start in (beginner or something else), chose beginner. It should
start up with a keyboard displayed. If you start it in the more advanced
mode, you can still bring the keyboard display up using
Instrument->Virtual Keyboard.
You should now see zynaddsubfx on the left side of the connections window
and some sound-channels on the right (on my system the sound is alsa_pcm).
Expand both. If you see lines connecting them, skip the rest of this
paragraphy. Otherwise, click out_1 on zynaddsubfx and playback_1 (or
whatever) on the right. Click "Connect". Do the same for channel 2 of
each. Lines will now appear connecting them.
At this point you should hear some clicks and tones when you click the
mouse on the virtual-keyboard keys. To get a better instrument sound,
click on Instrument->Show Instrument Bank. There'll be an *empty* dropdown
box. Click on that and it will list some categories. Select one of those
and the instrument bank will be listed. Click the instrument you want. Now
the virtual keyboard should play it.
Chances are you'll be getting all kinds of xruns in JACK Control's
Messages window, and the sound will be a little scratchy. Go to Setup in
Jack Control and keep increasing Frames/Second until the xruns go away.
Note the effect that increased values have on your latency. Opinions of
acceptable latency vary from 3 millisconds to about 30 milliseconds,
depending on who you ask. On a 2.2 Ghz CPU I use a Frames/Second setting
of 256, which gives me a latency of about 11 milliseconds.
Now it's time to plug in your keyboard. Plug it in and go to the
connections window again. Click the MIDI tab and you should see a new
MIDI device on the left. You want to expand it, expand ZynAddSubFX on the
right, and connect the MIDI channel on the left to ZynAddSubFX's
input channel on the right. Now when you press keys on the Korg you
should hear a tone. You can change the instrument sounds in zynaddsubfx.
Now just for a little fun (and to become more comfortable with JACK), you
can start up additional copies of zynaddsubfx. In the Connections
Window, connect all their outputs to the same audio inputs as before.
Configure each zynaddsubfx for a different instrument. Now you can play
different instruments on the different virtual keyboards.
By now you will have a good overview of setting up MIDI applications under
Linux and routing them with JACK. The UbuntuStudioPreparation page will
go a lot easier now.
You're likely to end up with Rosegarden as your MIDI editor. I haven't
used it too much myself but I did play with it for about an hour and as
best I can tell it has no way of giving sound to the physical keyboard as
you're using it to enter notes. I had to send my keyboard's MIDI output
both to zynaddsubfx and to Rosegarden. This seems a bit kludgy so I may be
missing something.
Just post back in this thread if you have any problems. I'm no expert but
I usually manage to stumble through things.
--- Platinum Xpress/Win/WINServer v3.0pr5
* Origin: Omicron Theta BBS (1:261/20)
|
