Linux-audio-dev April 2023

linux-audio-dev@lists.linuxaudio.org

6 participants
5 discussions

stereospread.lv2 - Stereo spreading plugin (conjugate random phase all-pass filter pair)

by Florian Paul Schmidt

Hi, I wrote a small plugin for spreading mono content to stereo and I would like to receive some feedback on it from people more knowledgable in DSP matters than me. It has one nice property: It spreads the signal over the spectrum by way of a conjugate pair of random phase all-pass filters, and since it's a conjugate pair it sums back to unity when down-mixing to mono. So, no ugly comb filter effects like when downmixing a Haas-expanded signal. https://github.com/fps/stereospread.lv2 The page has an example sound.. How it works: It's actually rather simple: 1. create a vector of random phases (matlab notation): filter_length = 1000; spread = pi; hfft1 = exp(-1i*(spread*rand(filter_length,1) - spread/2)); And for the second filter just take the complex conjugate: hfft2 = conj(hfft1); This ensures that what is a phase theta in the first filter becomes a phase of -theta in the second filter, and summed that just gives a phase of 0. 2. Then assemble the coefficients such that it corresponds to a fft of a real signal and do the inverse fft (possibly I have a small error here which i needed to fix with the 'symmetric' flag in matlab): f1 = ifft([1; hfft1; conj(hfft1((end-1):-1:1))], 'symmetric'); f2 = ifft([1; hfft2; conj(hfft2((end-1):-1:1))], 'symmetric'); 3. The two IRs f1 and f2 implement the pair of filters and can be applied via convolution (which the above plugin does). It seems to be possible with little ill effect to reduce the length of the filter down to a size of 50 samples or so by just cutting it off before the convolution. What do you think? Kind regards, FPS -- https://dfdx.eu

1 year, 11 months

liquidsfz-0.3.2

by Stefan Westerfeld

liquidsfz-0.3.2 has been released The main goal of liquidsfz is to provide an SFZ sampler implementation library that is easy to integrate into other projects. A standalone jack client and a LV2 plugin is also available. liquidsfz is implemented in C++ and licensed under MPL-2.0. The release tarball can be downloaded here: https://github.com/swesterfeld/liquidsfz#releases Overview of Changes in liquidsfz-0.3.2: * Fix crashes triggered by Carla while saving without path * Allow multiple overlapping notes during sustain (#38) * Provide cross compiled LV2 plugin for Windows * Use LV2_STATE__freePath if available (fixes LV2 on windows) * Fixes for building on macOS and Windows * Improve tests and CI checks -- Stefan Westerfeld, http://space.twc.de/~stefan

2 years

snd-firewire-ctl-services 0.1.0 released

by Takashi Sakamoto

Hi all, This is a short announcement about a new release of snd-firewire-ctl-services project. After development for mostly three years[1], version 0.1.0 is released today. If you have FireWire audio device and interests in ALSA support, the release would be worth to check out. * https://github.com/alsa-project/snd-firewire-ctl-services/releases/tag/snd-… The project provides user space service programs to operate digital signal processing function in devices supported by ALSA firewire stack. If using such device, you can configure DSP functions such as the volumes of device. For some device, effects such as dynamics and equalizers are also configurable. Available devices are listed in README.rst of the project. The service programs work as 'message broaker'. ALSA control applications are available for end-user interface to communicate to the service programs[2]. The device connected to IEEE 1394 bus is the peer. The service programs receives messages from both ends, then translates and convert the messages to send to the opposite end. Against your expectation, the project provides neither GUI programs nor end-user interfaces. I know that the user experience is heavily on look-and-feel on the GUI programs, while it is out of the aim of project. I daily use quashctl in QasTools[3] and it is pretty good to me for such ALSA control application. If encountering any issue, please file it to github repository[4]. README should be helpful to new users. Thanks for your support and long patience to ALSA firewire stack. [1] https://lists.linuxaudio.org/hyperkitty/list/linux-audio-dev@lists.linuxaud… [2] For TASCAM FireWire series, ALSA sequencer application is such end as well to operate control surface. [3] https://gitlab.com/sebholt/qastools [4] https://github.com/alsa-project/snd-firewire-ctl-services Regards Takashi Sakamoto

2 years

I'm being stalked, please be weary

by Jeanette C.

Hey hey, I am being stalked and the stalker has already contacted people I am connected with. Please, if anyone contacts you with any request, be weary. It's a plain name gmail address. Thank you and sorry to bother you! 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 Do you even know what I like Just what I'm living for, What I adore <3 (Britney Spears)

2 years

[LAA] New LV2 plugin: B.Silent

by Sven Jaehnichen

Hi, worried about the daily life noise level? But you only want a bit - silence? Then B.Silent is the virtual instrument to make your dreams come true. B.Silent is a unique MIDI instrument to produce silence in highest quality. Choose between 8 hand-selected types of silence provided as built-in presets to play silence in a never heard cleanliness. No background noise, no distortion, no glitches, only pure silence. Github: https://github.com/sjaehn/BSilent Video: https://www.youtube.com/watch?v=6-8g2qBZhSI Enjoy the silence! Released April 1, 2023 Sven

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Linux-audio-dev April 2023