On 2/7/21 12:11 PM, Tom Peters wrote:
Hi, I am a beginner with Rosegarden and indeed with sound editing. I am
struggling with what appears to be everybodies first problem: getting
sound out of my computer.
First of all, I just want to take a moment to hang my head in
disappointment that this is still so complicated 20 years after I first
used Rosegarden. Twenty years!
but it is not clear whether I need to use (and configure in RoseGarden)
both ALSA and JACK, or one of them excluding the other, or that they
co-exist. I would appreciate some elaboration.
ALSA is basically the low level sound driver handler, and it provides
MIDI communication functionality. JACK is a low latency audio server
that allows multiple applications to share the hardware. These days,
there is also PulseAudio, which is basically a high latency audio server
that also allows multiple applications to share the hardware.
Latency matters, because you generally want things to be as responsive
as possible. If you press a key on a keyboard or enter a note into
Rosegarden, you want to hear the note at that time, not 1/3 of a second
later.
What I have now:
Kubuntu 20.04
As do I.
Rosegarden "Yesterday" 19.12 (packaged with Kubuntu).
When I first started Rosegarden it warned me I need a software
synthesizer, specifically QSynth: but QSynth is not in Ubuntu.
Sure it is.
$ apt-cache search qsynth
qsynth - fluidsynth MIDI sound synthesiser front-end
RoseGarden appears to start jackd:
/usr/bin/jackd -T -ndefault -T -d alsa
Rosegarden can and will start JACK if you don't already have it running,
but if you want to use QSynth, it's better to start JACK and QSynth
before you start Rosegarden.
You installed QJackCtl. That's the best place to start. Close all audio
applications, then start QJackCtl. The default setup is generally an
acceptable starting place.
Actually, let's back up. Here are the Ubuntu Studio packages I have
installed myself:
$ dpkg -l|grep ubuntustudio|cut -d \ -f 3
ubuntustudio-audio
ubuntustudio-audio-core
ubuntustudio-audio-plugins
ubuntustudio-controls
ubuntustudio-lowlatency-settings
ubuntustudio-performance-tweaks
I also have the Ubuntu Studio kernel:
$ dpkg -l|grep latency|cut -d \ -f 3|grep 5\.4\.0-65
linux-image-5.4.0-65-lowlatency
linux-modules-5.4.0-65-lowlatency
These packages bring in a bunch of audio and synth plugins, as well as a
kernel that better supports low latency audio. You will want to install
all that stuff, then reboot to put the new kernel to use.
Let's see... The actual package to install whatever the current
lowlatency kernel is would be:
linux-image-lowlatency
I don't remember if pulling in the ubuntustudio packages pulled in that
one or if I had to install manually. Anyway, get it installed, boot, and
after you're running again, check to see that it's running.
Command line stuff is easier to post in an email, so the command line
way is:
$ uname -a
Linux omnitonic 5.4.0-65-lowlatency #73-Ubuntu SMP PREEMPT Mon Jan 18
18:17:38 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
The key words to look for there are "lowlatency" and "PREEMPT," and
these indicate that I have the right kernel running. By default (still,
20 years later, sigh) Linux isn't a friendly environment for audio,
because it puts the needs of having 10,000 simultaneous users ahead of
other considerations. On a home audio computer, you typically just have
one user logged in, and you want your audio to work well, even if it
impacts other processes. That's what this gobbledegook is all about.
I apologize for the fact that I'm rambling, and this message is a bit
disorganized. I haven't discussed this topic in a very long time.
So my question is:
what is missing in the components and configuration?
After you've installed the bits from ubuntustudio and booted your new
low latency kernel, log into your desktop.
First, run QJackCtl. The default settings may work. If it doesn't start
automatically, try hitting the start button.
If that doesn't work, we'll get into configuring it.
Once QJackCtl says "started" and it's showing green, start QSynth.
I just did that, and it came up in the system tray. Click the system
tray icon to pop up the QSynth window.
Click the Setup button. Click the Audio tab. Set audio to "jack" and
check "auto connect JACK outputs."
Click the Soundfonts button.
Now... Hmmm... This is where my local setup isn't going to be helpful.
If you don't already have it installed, go install:
fluid-soundfont-gm
That will get you a soundfont in /usr/share/sounds/sf2 somewhere. In
fact, your out of the box QSynth install may already be pointing at:
/usr/share/sounds/sf2/FluidR3_GM.sf2
If not, point it that way. Now save the config and start QSynth's
engine. I think it will ask "do you want to restart the engine" or
something along those lines. Sorry, not actually changing my own config.
So with those two pieces in place, now you can start Rosegarden and load
a demo file. It should play. Maybe.
Sorry again for the long, rambling tone of this reply. Hopefully this
can serve as a jumping off point for a discussion that ultimately proves
helpful to you.
--
D. Michael McIntyre
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