Linux-audio-user October 2024

linux-audio-user@lists.linuxaudio.org

23 participants
15 discussions

Tape emulation - is it worth the effort ?

by Fons Adriaensen

Hello all, The purpose of this post is to gather some opinions on the use of 'tape distortion' plugins. The way an analog magnetic tape recorder distorts the signal is quite complicated. The non-linear response is mainly due to the hysteresis of the magnetisation process, and how this interacts with the HF bias added to the recorded signal. Simplifying things a bit, as the tape moves past the recording head and away from it, it goes through several cycles of an hysteresis loop with decreasing amplitude, and it finally converges to some value more or less proportional to the signal. The bias signal itself does not remain on the tape, or at most at a very low level. The same process but with just a very high level HF bias is used to erase the tape. Simulating this accurately is quite complicated, and very CPU intensive. The sample rate must be at least twice the bias frequency (around 100 kHz for 'pro' equipment) and for each sample you need to evaluate the hysteresis loop up to a hundred times (depending on tape speed) to simulate the convergence. Over the past few months I've written the code to do this, with the aim to present a useful 'tape emulation' plugin at the next LAC. It uses a somewhat simplified form of the Preisach algorithm for the hysteresis. <http://kokkinizita.linuxaudio.org/linuxaudio/downloads/preisach-model.pdf> But the first results are somewhat sobering. Have a look at <http://kokkinizita.linuxaudio.org/linuxaudio/downloads/tapesaturation.png> This shows the tranfer function (recorded magnetic signal as a function of the input) for three values of the HF bias. The blue line is what you get without bias. It result in a very smooth saturation for high level signals, but a low amplitude signal will be severly distorted due to the flat region around zero. As bias level is increased, this effect is reduced and the low level gain increases up to some maximum. This is shown by the orange curve. The recommended way to set the correct bias level is to further increase it until the small signal gain is reduced by a few dB (typically 1 or 2 dB, depending on tape type). This is shown by the green curve. The central part of this is very linear (less than 1% THD). But now the smooth saturation is almost transformed into hard clipping. The sharp bend in the curve occurs when the signal amplitude is higher than the bias amplitude. The only effect that remains in a complete simulation is the result of the EQ applied to the signal to be recorded. Higher frequencies have a 'self erasure' effect (which is nicely reproduced by the simulation) and so need to be amplified. The net result is that they will saturate at a lower input level. How much EQ is required depends mainly on tape speed, higher speeds need less. At the most popular 'pro' speed (381 mm/s) this would be something around 10 dB at 10 kHz. At the higher (762 mm/s) speed typically used for 'master tapes' it's just a few dB. So what does effectively remain of the 'smooth saturation and compression' that is claimed to give tape recording its magical 'warm' character ? Is it just a myth ? I also simulated the green curve directly without going through the complicated full simulation, and honestly, to me that sounds just the same. And unless you really use very high levels (much more than would actually be used) the net effect is marginal. Maybe the hard clipping can be useful when applied to individual tracks (e.g. drums or bass), but then there are much simpler ways to do this than 'tape emulation'. Comments invited !!

1 month, 1 week

Realtime-Kernel patch merged to mainline kernel after 20 years...

by Tobias Küchel

Cheers to Ingo Molnar! I am not sure how many users are interested in such news, since there might be still a linux-audio-dev community that I am not part of anymore. Nevertheless, it amuses me that basically half my life ago, I struggled and tested and read tons of stuff, invested a lot of time to get some nice audio stuff going on linux and some rather crappy hardware... and now, 20 years later, the foundation to all of it - a real-time kernel - did not disappear but was developed and maintained until the eagle has landed. Again, cheers to Ingo and all that contributed! Yours, Tobias.

2 months, 1 week

[ANN] Vee One Suite 1.1.3 - A Halloween'24 Release

by Rui Nuno Capela

Greetings (from the crypt), The 'Vee One Suite', the so called 'gang-of-four' 'old-school' software instruments, * synthv1 [1] as a polyphonic subtractive synthesizer; * samplv1 [2] a polyphonic sampler synthesizer; * drumkv1 [3] as yet another drum-kit sampler; * padthv1 [4] a polyphonic additive synthesizer. Are here released for the spooky Halloween'24 evening... All creepy delivered in dual form: - a pure stand-alone JACK client with JACK-session [5], NSM (Non/New Session Management [6]) and both JACK MIDI and ALSA MIDI [7] input support; - a LV2 instrument plug-in [8]. Change-log: - Prepping up next development cycle (Qt >= 6.8) The 'Vee One Suite' are free, open-source Linux Audio [10] software, distributed under the terms of the GNU General Public License (GPL) [11] version 2 or later. **synthv1 - an old-school polyphonic synthesizer [1] ** synthv1 1.1.3 (halloween'24) is out! synthv1 is an old-school all-digital 4-oscillator subtractive polyphonic synthesizer with stereo fx. LV2 URI: http://synthv1.sourceforge.net/lv2 website: https://synthv1.sourceforge.io http://synthv1.sourceforge.net project page: https://sourceforge.net/projects/synthv1 downloads: https://sourceforge.net/projects/synthv1/files - source tarball: https://download.sf.net/synthv1/synthv1-1.1.3.tar.gz - source package: https://download.sf.net/synthv1/synthv1-1.1.3-5.1.rncbc.suse.src.rpm - binary packages (openSUSE Tumbleweed): https://download.sf.net/synthv1/synthv1-jack-1.1.3-5.1.rncbc.suse.x86_84.rpm https://download.sf.net/synthv1/synthv1-lv2-1.1.3-5.1.rncbc.suse.x86_84.rpm - AppImage [9] package (JACK stand-alone only): https://download.sf.net/synthv1/synthv1-jack-1.1.3-5.1.x86_64.AppImage git repos: https://git.code.sf.net/p/synthv1/code https://github.com/rncbc/synthv1.git https://gitlab.com/rncbc/synthv1.git https://codeberg.org/rncbc/synthv1.git **samplv1 - an old-school polyphonic sampler [2]** samplv1 1.1.3 (halloween'24) is out! samplv1 is an old-school polyphonic sampler synthesizer with stereo fx. LV2 URI: http://samplv1.sourceforge.net/lv2 website: https://samplv1.sourceforge.io http://samplv1.sourceforge.net project page: https://sourceforge.net/projects/samplv1 downloads: https://sourceforge.net/projects/samplv1/files - source tarball: https://download.sf.net/samplv1/samplv1-1.1.3.tar.gz - source package: https://download.sf.net/samplv1/samplv1-1.1.3-5.1.rncbc.suse.src.rpm - binary package (openSUSE Tumbleweed): https://download.sf.net/samplv1/samplv1-jack-1.1.3-5.1.rncbc.suse.x86_84.rpm https://download.sf.net/samplv1/samplv1-lv2-1.1.3-5.1.rncbc.suse.x86_84.rpm - AppImage [9] package (JACK stand-alone only): https://download.sf.net/samplv1/samplv1-jack-1.1.3-5.1.x86_64.AppImage git repos: https://git.code.sf.net/p/samplv1/code https://github.com/rncbc/samplv1.git https://gitlab.com/rncbc/samplv1.git https://codeberg.org/rncbc/samplv1.git **drumkv1 - an old-school drum-kit sampler [3]** drumkv1 1.1.3 (halloween'24) is out! drumkv1 is an old-school drum-kit sampler synthesizer with stereo fx. LV2 URI: http://drumkv1.sourceforge.net/lv2 website: https://drumkv1.sourceforge.io http://drumkv1.sourceforge.net project page: https://sourceforge.net/projects/samplv1 downloads: https://sourceforge.net/projects/drumkv1/files - source tarball: https://download.sf.net/drumkv1/drumkv1-1.1.3.tar.gz - source package: https://download.sf.net/drumkv1/drumkv1-1.1.3-5.1.rncbc.suse.src.rpm - binary package (openSUSE Tumbleweed): https://download.sf.net/drumkv1/drumkv1-jack-1.1.3-5.1.rncbc.suse.x86_84.rpm https://download.sf.net/drumkv1/drumkv1-lv2-1.1.3-5.1.rncbc.suse.x86_84.rpm - AppImage [9] package (JACK stand-alone only): https://download.sf.net/drumkv1/drumkv1-jack-1.1.3-5.1.x86_64.AppImage git repos: https://git.code.sf.net/p/drumkv1/code https://github.com/rncbc/drumkv1.git https://gitlab.com/rncbc/drumkv1.git https://codeberg.org/rncbc/drumkv1.git **padthv1 - an old-school polyphonic additive synthesizer [4]** padthv1 1.1.3 (halloween'24) is out! padthv1 is an old-school polyphonic additive synthesizer with stereo fx. padthv1 is based on the PADsynth algorithm by Paul Nasca, as a special variant of additive synthesis. LV2 URI: http://padthv1.sourceforge.net/lv2 website: http://padthv1.sourceforge.net https://padthv1.sourceforge.io project page: https://sourceforge.net/projects/padthv1 downloads: https://sourceforge.net/projects/padthv1/files - source tarball: https://download.sf.net/padthv1/padthv1-1.1.3.tar.gz - source package: https://download.sf.net/padthv1/padthv1-1.1.3-5.1.rncbc.suse.src.rpm - binary package (openSUSE Tumbleweed): https://download.sf.net/padthv1/padthv1-jack-1.1.3-5.1.rncbc.suse.x86_84.rpm https://download.sf.net/padthv1/padthv1-lv2-1.1.3-5.1.rncbc.suse.x86_84.rpm - AppImage [9] package (JACK stand-alone only): https://download.sf.net/padthv1/padthv1-jack-1.1.3-5.1.x86_64.AppImage git repos: https://git.code.sf.net/p/padthv1/code https://github.com/rncbc/padthv1.git https://gitlab.com/rncbc/padthv1.git https://codeberg.org/rncbc/padthv1.git References: [1] synthv1 - an old-school polyphonic synthesizer https://synthv1.sourceforge.io http://synthv1.sourceforge.net [2] samplv1 - an old-school polyphonic sampler https://samplv1.sourceforge.io http://samplv1.sourceforge.net [3] drumkv1 - an old-school drum-kit sampler https://drumkv1.sourceforge.io http://drumkv1.sourceforge.net [4] padthv1 - an old-school polyphonic additive synthesizer https://padthv1.sourceforge.io http://padthv1.sourceforge.net [5] JACK Audio Connection Kit https://jackaudio.org/ [6] NSM, Non Session Management (legacy) http://non.tuxfamily.org/nsm/ New Session Manager https://new-session-manager.jackaudio.org/ [7] ALSA, Advanced Linux Sound Architecture https://www.alsa-project.org/ [8] LV2, Audio Plugin Standard, the extensible successor of LADSPA https://lv2plug.in/ [9] AppImage, Linux apps that run anywhere https://appimage.org/ [10] Linux Audio consortium of libre software for audio-related work https://linuxaudio.org [11] GNU General Public License https://www.gnu.org/copyleft/gpl.html See also: https://www.rncbc.org/drupal/node/2684 Enjoy the treats! - - - rncbc aka. Rui Nuno Capela

2 months, 2 weeks

[music] Song for piano and flute

by Jeanette C.

Hey hey, and here's the second one. This time it's a "proper composition", with more of a late 19th century feel. A more positive and intense piece as well. https://youtu.be/SukYCNZ82LU The piano had been played months before the flute could be recorded. Due to time considerations several takes had to be comp'ed, which you can hear. My apologies. Next time, there will hopefully be more time to forego that practise. Best wishes and, mainly, enjoy, Jeanette -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c I used to think I had the answers to everything But now I know ... :) <3 (Britney Spears)

2 months, 3 weeks

[ANN] QjackCtl 1.0.3 - An Autumn'24 Release

by Rui Nuno Capela

Hi everyone! QjackCtl 1.0.3 (autumn'24) is out! QjackCtl [1] is an aged yet modern, not so 'simple' anymore, Qt [2] application to control the JACK [3] sound server, for the Linux Audio [4] infrastructure. Change-log: - Long missing D-Bus method slot added: "reset" (dbus-send --system / org.rncbc.qjackctl.reset). - Graph: Node reference positioning changed to the top-left corner, improving the base snapping-to-grid perception. - Prepping up next development cycle (Qt >= 6.8) Website: https://qjackctl.sourceforge.io http://qjackctl.sourceforge.net Project page: https://sourceforge.net/projects/qjackctl Downloads: https://sourceforge.net/projects/qjackctl/files - source tarball: https://download.sf.net/qjackctl/qjackctl-1.0.3.tar.gz - source package: https://download.sf.net/qjackctl/qjackctl-1.0.3-4.1.rncbc.suse.src.rpm - binary packages: https://download.sf.net/qjackctl/qjackctl-1.0.3-4.1.rncbc.suse.x86_64.rpm - AppImage [6] package: https://download.sf.net/qjackctl/qjackctl-1.0.3-4.1.x86_64.AppImage Git repos: https://git.code.sf.net/p/qjackctl/code https://github.com/rncbc/qjackctl.git https://gitlab.com/rncbc/qjackctl.git https://codeberg.com/rncbc/qjackctl.git License: QjackCtl [1] is free, open-source Linux Audio [4] software, distributed under the terms of the GNU General Public License (GPL) version 2 or later [5]. References: [1] QjackCtl - A JACK Audio Connection Kit Qt GUI Interface https://qjackctl.sourceforge.io [2] Qt framework, C++ class library and tools for cross-platform application and UI development https://qt.io/ [3] JACK Audio Connection Kit https://jackaudio.org [4] Linux Audio consortium of libre software for audio-related work https://linuxaudio.org [5] GPL - GNU General Public License https://www.gnu.org/copyleft/gpl.html [6] AppImage, Linux apps that run anywhere https://appimage.org/ See also: https://www.rncbc.org/drupal/node/2683 Enjoy! - - - rncbc aka Rui Nuno Capela

2 months, 3 weeks

[music] Piece for flute and piano (with Ritual Notes)

by Jeanette C.

Hey hey, I have just released "A Moment of Passing", which my friend Ritual Notes and I wrote and performed together. The recording is a few months old, but I just got back my production environment. https://youtu.be/dmTR8Rm70sY My friend plays the flute, I play the piano. We did record it in two goes, since I don't have two headphones or anything. It's a sad little song, with a few sunnier moments and it came to be on the spur of the moment. There will be another song, which was properly composed, in two days time. Enjoy and best wishes, Jeanette -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c Make all the clouds disappear Put all your fears to rest <3 (Britney Spears)

2 months, 3 weeks

Guitarix.vst v0.4 Release

by Hermann Meyer

Guitarix.vst is the full blown guitarix stack as VST3 plugin for Linux, using Juce to wrap the guitarix engine into a VST3 plugin. It allow to load/save your presets, download presets from online and load external LV2 plugs and IR Files, like the guitarix stand-alone version. But all that as a VST3 plugin in your DAW. All parameters been exposed to the DAW, so accessible for automation. Other than the stand-alone, the VST3 version allows to switch the input to a real stereo input, so it may match better your channel strip in the DAW. For Hdpi users, the GUI is full scalable. New in this release: - Add support for Parallel Processing (process second mono chain in parallel when stereo is selected) - Fix downloading online presets - Update included Juce modules to v7.0.12 - Hide disabled controllers in main amp when no-tube is selected - Update included guitarix engine to latest git head Project Page: https://github.com/brummer10/guitarix.vst Release Page: https://github.com/brummer10/guitarix.vst/releases/tag/v0.4 regards hermann

3 months

Touchpad to MIDI

by Will Godfrey

Does anyone know of software that can generate MIDI messages from a touchpad? The idea would be to send CCs to a sequencer or soft synth, but being able to send it to an external hardware device would also be very useful. -- Will J Godfrey https://willgodfrey.bandcamp.com/ http://yoshimi.github.io Say you have a poem and I have a tune. Exchange them and we can both have a poem, a tune, and a song.

3 months, 1 week

Fluida v0.9.3 released

by Hermann Meyer

Fluida is a LV2 wrapper around Fluidsynth for Linux and Windows allowing to load and control Fluidsynth as LV2 plugin. This release of Fluida add support for Fluidsynth SoundFont Modulators Envelope and Filter with the following MIDI bindings: - MIDI CC 73 Soundfont modulator Envelope Attack Time - MIDI CC 72 Soundfont modulator Envelope Release Time - MIDI CC 74 Soundfont modulator Filter Cutoff - MIDI CC 71 Soundfont modulator Filter Resonance Project Page (Source Code): https://github.com/brummer10/Fluida.lv2 Release Page (Binaries): https://github.com/brummer10/Fluida.lv2/releases/tag/v0.9.3

3 months, 2 weeks

Monitor ports - why do I want this?

by Mitsch

Hi! Using jack a long time, now. I never activated "monitoring" on my RME HDSP 9652 because I did not know how to make use of it. In qjackctl the big block of additional 26 ports was always in the way… Now, with pipewire, monitoring is activated by default. Surely, I can deactivate it through some configuration I have to investigate further. (Or a neat person here tells me how… :) ) But before I do this I want to make sure not cancelling a handy feature I would have definitely used if I was smart enough… So: What are these "monitor" ports and what can I do with them? And sorry for the newbie question although I'm not a newbie, at all… Greets! Mitsch

3 months, 2 weeks

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Linux-audio-user October 2024