hpr-knowledge-base/hpr_transcripts/hpr0755.txt

Episode: 755
Title: HPR0755: LINUX JAZZ  BALLIN' THE JACK
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr0755/hpr0755.mp3
Transcribed: 2025-10-08 01:56:17

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Welcome to Hacker Public Radio. This is Tony Denton, also known as Barryman, with my third podcast.
In my last show, I said that I will be explaining how I use Linux in the production of a website.
Well, I've since decided to hold this topic over until the next episode.
This episode, I've called Ball in the Jack.
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At first, my thanks again go to Claudio M and to Claudio M for their comments.
Claudio M asked whether the music segues were by me playing.
Well, yes, all the music you hear is either played by me on the clarinet, tenor or baritone saxophones,
or compiled using the music software that I outlined in my earlier podcasts.
Claudio suggests that I record some loops and post them on freesound.org.
I think that's a great suggestion. I'm looking into doing just that.
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The Jack Audio Driver. I'm sure that I'm not alone in wrestling with the Jack Audio Driver.
Some people have it relatively easy when installing Jack.
But my hardware is mostly old kit recycled, so it's a bit more temperamental when it comes to compatibility with the latest Linux kernels.
Although to be fair, with each subsequent distro update, audio does seem to get easier.
For any serious audio work, it is essential that the Linux kernel operates in real-time mode.
Prior to kernel 2.4, it was necessary to install a specially compiled kernel to operate in real-time mode.
From 2.4 onwards, however, all kernels have real-time capability built into them.
It just needs switching on through the software, in this case Jack, and then editing a configuration file.
When you load Jack for the first time, or reinstall it after an update say,
you are asked to tick a box if you want to run Jack in real-time mode.
You should make sure you tick this box if you are into any half-series audio work.
If you miss it, or simply turning it on in an already installed copy of Jack, then you can do it through the setup tab from the Jack Control interface.
On the setup page under parameters, the first tick box will turn on real-time mode.
On this same page, the sample rate can be set. I use 44100 for maximum compatibility.
And the buffer size of frames rate can also be reset.
Even on my old single-core 1GHz AMD machine, I can get away with setting the frames rate to 256,
which produces a very acceptable 11.6 millisecond latency.
Of course, you don't have to do all this if you just want to opt for the simple route and use Audacity.
For programs such as Ada, or any amount of other music-related software,
however, real-time operation is essential if you want to avoid extra runs and stuttering audio.
If you've got this far, great!
Now here comes the more geeky bit, and don't worry if you're having difficulty hanging all this together as I speak.
I shall put all the information in the show notes.
Next is the editing of the configuration file.
You can't use real-time audio unless you carry out this next step.
Even though Jack is now running in real-time mode, you're not yet allowed to use real-time scheduling.
This is turned on by the addition of two lines of code to the file limits.com,
in the slash Etsy slash security folder.
I find the easiest way to edit a system file is by using GetIt as a super user.
So I enter sudo, spacegetit, space slash Etsy, slash security slash limits.com.
And after entering my password, add the following two lines before the hash end file marker.
At audio, dash RTPRIO, space99, and at audio, dash Memlock, space unlimited.
This means you have to make sure you're part of the audio group, which in Linux, you can check via the system slash administration slash the users and groups tab.
Or you can simply use your user name instead of at audio, which in my case is Donny Denton.
The first line, RTPRIO, space99, sets the real-time priority to 99%.
You could set it to 100%, but setting it to 99 just gives that little bit of headroom to avoid locking up the CPU in the event of a crash.
The second line, Memlock Unlimited, means that the audio function has unlimited access to all the memory.
And that's it, you should now be able to operate your audio functions in real-time mode.
Few, that was all a bit heavy, but as I said, I shall put all the details in the show notes.
Now when you load and start jack, and the easiest way to do this is with the jack control GUI, Q jack control, which is available in the Linux software repositories.
Now when you start jack, the RT symbol shows up in the display window and you're set to go.
Now that's what I call ball in the jack.
Now when you load and start jack, you're set to go.
Now when you load and start jack, you're set to go.
Now when you load and start jack, you're set to go.
Now when you load and start jack, you're set to go.
Now when you load and start jack, you're set to go.
Now when you load and start jack, you're set to go.
Updating my hardware.
It was only in my last podcast that I described in fair detail my hardware setup.
Well, I've pushed the boat out, so to speak, and invested in an audio mixer.
The mixer I have chosen, is a Beningere XX-1204 USB mixer.
mixer. This mixer has on-board USB audio interfaces and four mono and two stereo input channels
all balanced or unbalanced. And the XLR inputs have very good quality mic preamps. Each input
channel strip has three band EQ and band functions and two AUX sends. On my X model the AUX
two control sends the signal to an effects processor that has 16 effects with 5 reverb
effects, four ambience delay effects, three modulation effects, two detune pitch effects
and a couple of combination effects. These effects should prove useful to future projects.
In addition each of the four mono inputs has a studio grade compressor on the strip. The
mixer is portable enough to be useful on live gigs as well as providing a reasonable
quality of audio for my studio based music activities and the price of the mixer is right
just under 140 pounds sterling. Acquiring this now allows me to add my ageing Yamaha PSR
350 keyboard into the mixer as another input and sound source. One of the consequences
of this acquisition is that I cannot use the Berringer C1U USB microphone with the mixer.
I can however continue to use the microphone for quick direct input recordings into the
laptop. Another advantage of adding the mixer is that I can link the Zoom H4N in to
allow separate recording of the voice and voice signals and the Zoom can of course itself
simultaneously record up to 4 tracks, 2 stereo and 2 mono. Maybe this will be the start
of double-end recording if I can find a suitable parameter link with.
But considering my software bag, all this updating of hardware has caused me to have
another look at the software that I use. For example this podcast is now being recorded
in ARDA, not Audacity. ARDA has become my main digital audio workstation for serious music
projects. I'm only just beginning to get to grips with it, but already I recognise
that it is a highly polished professional piece of software that is close to comparable
with Cubase or Logic Pro for all but the most serious professional musician. I'm still
exploring its capabilities for my particular setup and you'll probably do a podcast on
ARDA sometime in the future. I tend to subscribe to ARDA to help keep Paul Davis developing
the program and I urge others to do so. For the time being I shall continue to use Audacity
as the mastering software with Clato's configuration as I mentioned in my last podcast.
The advantage of using Audacity for mastering is that the noise reduction and compressor
and normalizer plugins are so easy and effective to use. Also another very useful program
for setting or editing ID3 tags is KID3 tag. This little program accesses more ID3 parameters
and can be set via the Audacity export function and allowing cover art to be added.
I shall for the moment have to continue to use band in a box and civilian six in virtual
box for my backing tracks and scorewriting. Although I am currently trialling MMA musical
MIDI accompaniment about the closest I can find in Linux to band in a box. Also I'm looking
at Muse and Lillipond in the hope that I can get to the point where I can dispense with the
Windows-based software altogether. As before I write the backing tracks in band in a box without
the melody of solo track and capture the backing track on the Zoom H4N now mounted to a
photography tripod and set up directly in front of the stereo speakers. The track is then exported
and brought into Arda where the solo track is recorded alongside and mixed with it. It's still a
bit experimental at this stage but I'll let you know how I get on.
Well that's about it for now. My website and blog can be found at www.tonydenton.com
and I'm on Twitter as Tony Denton. My identity can name is Barryman and I'm occasionally found
when I see also as Barryman. Cheers for now.
Thank you for listening to Hacker Public Radio for more information on the show
and how to contribute your own shows visit HackerPublicRadio.org