Linux-audio-user May 2014

linux-audio-user@lists.linuxaudio.org

75 participants
58 discussions

Ground lifts, TRS, etc. to PA? USB/other signal crossover to audio?

by Jonathan E Brickman

Last night I came to at least a working resolution of a really weird problem. I'm hoping others can tell me what is really going on here, and what best to do about it. I am not an electrical engineer or electrician or anything like that, I just learned a lot from my dad and friends and trial and error. This has to do with my MIDI synth, which is a headless Linux box, often used with three Yoshimis running simultaneously. Input is just MIDI, either through USB direct from keyboards or through USB MIDI adapters. The problem is other really odd high-pitched non-static signals which are contaminating the audio, when plugged into any of three different PAs. The contamination has occurred no matter whether I use motherboard 1/8" jacks, FrontX RCA jacks wired into the motherboard, custom-built Switchcraft 1/4" TS jacks wired into the motherboard, a Prosonus USB, or a Behringer FCA202. It occurs to varying degrees, not predictably, with all of them. AC power ground lifts sometimes have helped, sometimes not, but not predictably: plugging into the same PC, one week the extra signals will be there, the next week about 75% less, et cetera. Same with different MIDI methods. Once I knocked out 90% plus by going from USB direct to MIDI through the Presonus, and then two weeks after that it went up again (still using the Presonus) to about half what it had been. I have tried AC ground lifts on amp, keyboard, and the box. Sometimes the signal goes away when there is nothing connected via USB; sometimes not. Good AC grounding has been explicitly made excellent and tested very thoroughly by at least two professional musicians at one of these locations. Perhaps the oddest thing I have noticed about the extra signal, sometimes, is when it comes. I usually connect the synth box through a Roland volume pedal to PA. If the pedal is entirely absent, it always comes. But if the pedals are there, about half of the time, the extra signal comes in most when the pedal is in the lowest/zero volume position, and least/zero when the pedal is in the highest/maximum volume position. The other half of the time, the signal is always there and always the same volume, no matter what the position of the pedal! About three days ago, reviewing for the umpteenth time the whole memory-history of this project, I remembered one thing I did a long time ago which seemed to knock out the extra signal altogether (back then, it was a 60-cycle hum): I used a Radio Shack inline-audio ground lift device, a 2" black barrel with two short double-RCA-male cables. I wore out several sets of adapters on that thing which is why I abandoned it. But it had worked more positively than anything else I tried. And I found other reports on the WWW of similar setups not necessarily involving 60-cycle in the problem signal. So I investigated the state of the art of inline audio ground lifts, found a whole lot more easily findable options than there had been then (might have been ten years ago), found that Behringer among others is making one using 1/4" TS/TRS, ordered the Behringer, tried it last night, and voila, lovely gorgeous silence until the Great Key-Pressing!!! So. I would like to rigorize this outfit a bit more; right now I have to play using the box plugged via Firewire into the FCA202, thence via TS into the ground-lift, and then to the PA via another TS. Here are a few questions. 1. I would love to be using 1/4" jacks built into the box. But clearly clear grounding is a terrible problem. Sounds like I have to have the 1/4" jacks on a non-metal plate; do you think? 2. What is the real advantage of TRS vs. TS? Some of the audio ground-lifts advertise TS/TRS conversion and/or problem resolution; what is the deal??? Does TRS handle longer runs better? Whenever I have the case plate reengineered, should I have it done with TRS? 3. The 96 kHz audio available via Firewire is clearly helpful in the upper registers. Fitting it along with a 1/4" double inline audio ground lift device into my box, is somewhat less than appealing, especially because the metal cases of both the Fireware and the ground lift devices, will be in contact with PC case metal, possibly resulting in more contamination. What to do ???!??? Jonathan E. Brickman Ponderworthy Music | jeb(a)ponderworthy.com<mailto:jeb@ponderworthy.com> | (785)233-9977 | http://ponderworthy.com

10 years, 10 months

LV2 note2midi plugin

by Lucas Takejame

Hello guys, recently I assembled note2midi LV2 plugin based on the ‘aubionotes’ from lib aubio's example folder. You can find it at this link https://github.com/portalmod/mod-utilities/tree/master/Note2Midi and I'm hopping you guys could help me to improve this plugin so it can be more reliable for using with guitar and bass. The majority of the tests were made using pure sine waves. I barely know how the algorithms ‘onset’ and ‘pitch’ detection works, that’s because I don't know much more how the note2midi can be improved. I appreciate if someone could give me some tips =)! Att, Lucas

10 years, 10 months

LAC

by Will Godfrey

Had a really good time there. Great community spirit and lots to see (and talk about!) -- Will J Godfrey http://www.musically.me.uk Say you have a poem and I have a tune. Exchange them and we can both have a poem, a tune, and a song.

10 years, 10 months

96 kHz -- a bottleneck somewhere

by Jonathan E Brickman

I decided to try 96 kHz audio with the S.R.O. (Supermega Rumblic Organ), my slightly Aslan-like synth (it is not a tame device really), and found items which may be of interest: 1. At 96 kHz, schedtool definitely matters. Taking it out increased xruns a lot. I tried to figure out what was interfering via htop, but it was very unclear. So I'm keeping the schedtool for now. I could believe that if I reengineer for a zero-X default setup (likely to happen in the future) this problem might go away, X and the desktop certainly do have lots of demands. I *think* the only big piece missing for me in this is keymapping, I use F-keys to switch patches, quite easy in both LXDE and MATE. 2. At 48 kHz, I could run stereo, i.e., all three Yoshimis' dual outputs combined by Jack separately, so each output of my FCA202 had a separate signal, with different separations as Yoshimi is prepared to do. But at 96 kHz I started to get rare xruns doing this. Tried a number of things, didn't figure out why. So I tried using just one output of each Yoshimi and then having Jack copy them all to both outputs; xruns gone. Some of my patches -- especially strings-related -- are quite a lot improved by the shift to 96 kHz, the audio detail at the high third of my 88 is much better. Not very surprising from a mathematical point of view of course. I don't use stereo output anyway, I play in ensemble and I need to leave some of the ambient audio thought-room for others, so I'm leaving things as they are unless a solution arises for possible use in recording. 3. The Jack-internal MIDI ports are enormously more handy for portability, because since they retain the same Jack port names for any ALSA MIDI hardware, I can plug in any USB MIDI adapter or USB keyboard and expect things to work without getting into GUI at all. So based on the input from excellent LAU folks, I decided to try an alsarawmidi slave driver via jack_control, thinking that perhaps I mightn't have to worry about the jitter at 4GHz; and lo and behold, all working well so far. For any who may be interested, here is START-INITIAL (run at boot) and patch script START-SRO: ---- begin START-INITIAL, run at boot ---- #!/bin/bash echo '' echo 'Initiating environment...' echo '' nohup /home/jeb/startx11vnc.sh & echo '' echo 'Cleaning up old logs...' echo '' rm ~/.log/jack/jackdbus.log rm ~/.log/a2j/a2j.log rm ~/.log/lash/lash.log echo '' echo 'Starting jackd via dBus and configuring...' echo '' jack_control ds firewire jack_control dps capture 0 jack_control dps playback 0 jack_control dps rate 96000 jack_control dps period 64 jack_control asd alsarawmidi jack_control start jack_control eps realtime true jack_control eps realtime-priority 75 jack_control eps clock-source 1 /home/jeb/START-SRO & ---- begin START-SRO, run to start patch SRO ---- #!/bin/bash # Stop any running audio elements echo "Stop any running audio elements..." killall -9 -w yoshimi fluidsynth zita-j2a aj-snapshot guitarix calfjackhost non-mixer rakarrack mididings lashd killall -9 -w yoshimi fluidsynth zita-j2a aj-snapshot guitarix calfjackhost non-mixer rakarrack mididings lashd # Remove all connections # echo "Stopping a2j..." # a2j_control stop echo "Stopping Jackd to remove all connections..." killall -9 -w jackdbus killall -9 -w jackdbus jack_control stop echo "Starting Jackd..." jack_control start sleep 2 # Running a2j -- needful to use ALSA MIDI devices with # zita-a2j, which uses the 'dummy' driver in Jack # echo "Starting a2jmidid..." # a2j_control ehw # a2j_control start # Start all relevant audio elements echo "Start all relevant audio elements..." nohup schedtool -R -p 90 -e mididings -f /home/jeb/Combine.py \ > /home/jeb/LOGS/Combine.log & nohup schedtool -R -p 90 -e calfjackhost --client CalfSRO \ eq12:SRO ! reverb:SRO ! Compressor:SRO \ > /home/jeb/LOGS/calfjackhost-SRO.log & nohup schedtool -R -p 90 -e yoshimi -N YoshSRO1 -j -l /home/jeb/YOSHIMI/SROpart1.xmz \ > /home/jeb/LOGS/Yoshimi-SRO1.log & nohup schedtool -R -p 90 -e yoshimi -N YoshSRO2 -j -l /home/jeb/YOSHIMI/SROpart2.xmz \ > /home/jeb/LOGS/Yoshimi-SRO2.log & nohup schedtool -R -p 90 -e yoshimi -N YoshSRO3 -j -l /home/jeb/YOSHIMI/SROpart3.xmz \ > /home/jeb/LOGS/Yoshimi-SRO3.log & sleep 2 # And lastly, create jackd connections using aj-snapshot echo "And lastly, create jackd connections using aj-snapshot..." cp /home/jeb/AJSRO.xml /home/jeb/AJRunning.xml nohup schedtool -R -p 90 -e aj-snapshot -d AJRunning.xml & -- Jonathan E. Brickman Ponderworthy Music | jeb(a)ponderworthy.com<mailto:jeb@ponderworthy.com> | (785)233-9977 | http://ponderworthy.com

10 years, 11 months

looking for commercial sfz sample libraries

by Nils

I am looking for commercial sfz libraries. This means intended and sold as sfz, not converted, not user- or script-generated sfz mappings. The bigger the better. More expensive: better. Needs proprietary sfz-extensions/engine? Also fine. This is not for personal use but for Linux Audio research. Do you know any? greetings, Nils http://www.nilsgey.de

10 years, 11 months

AVLinux on KVM? -- doh

by Ken Restivo

Just realized, I could just copy the AVLinux files onto a loop devices using a rw file system, rename isolinux to syslinux, and go from there. Sorry for the noise. -ken

10 years, 11 months

lac2014 photo gallery

by Rui Nuno Capela

howdy, still playing catch-up with the post-lac traumatic syndrome... all those unedited photos that were taken by me during the lac2014@zkm-karlsruhe, are now online: http://www.rncbc.org/lac2014 i suck at photography and it shows :) cheers -- rncbc aka. Rui Nuno Capela ps. please report any concerns you may find, if any, privately.

10 years, 11 months

lac2014 video gallery

by Rui Nuno Capela

howdy again, inthe same vein as my previous post re. lac2014 photo gallery, here goes all the unedited videos as taken by me during the lac2014@zkm-karlsruhe: - LAC2014@ZKM-Karlsruhe - Linux Sound Night (1) http://www.youtube.com/watch?v=-qJETwQi2XQ - LAC2014@ZKM-Karlsruhe - Linux Sound Night (2) http://www.youtube.com/watch?v=eHPIZhDLQ_s - LAC2014@ZKM-Karlsruhe - Linux Sound Night (3) http://www.youtube.com/watch?v=NU0giL8KRhE - LAC2014@ZKM-Karlsruhe - Linux Sound Night (4) http://www.youtube.com/watch?v=8m5pNyq5O-k - LAC2014@ZKM-Karlsruhe - Linux Sound Night (5) http://www.youtube.com/watch?v=6f4gOqYj3Zk - LAC2014@ZKM-Karlsruhe - Linux Sound Night (6) http://www.youtube.com/watch?v=sWqFmmbrXz4 - LAC2014@ZKM-Karlsruhe - Linux Sound Night (7) http://www.youtube.com/watch?v=LBp_wJNGCVo - LAC2014@ZKM-Karlsruhe - Linux Sound Night (8) http://www.youtube.com/watch?v=qxsLO1FIjE4 i suck at cinematography and it shows :) im specially begging for all the depicted performing artists (mainly Jeremy and superdirt²) to help me on their own proper tag lines and descriptions, please. nb. the videos are currently unlisted. you need the direct explicit urls to watch them. cheers -- rncbc aka. Rui Nuno Capela

10 years, 11 months

New Website and Music

by Gerald

Hi folks, I would like to announce the new website of my Band Jimson Drift (www.jimson-drift.de). For now its in German, but I think the word 'Songs' is clear enough ;) Just 3 Songs there, but are more to come, for e.g some of these older ones: www.jamendo.com/en/list/a62900/groove-venture, with the new Band Members . It's lovely here in Karlsruhe at LAC2014 and I'm happy to meet some of the key devs of linux audio, thanks for your efforts and check the Dank& Links section of the website. Regards, Gerald

10 years, 11 months

AVLinux in KVM?

by Ken Restivo

I was going to play around with some studio stuff, don't have a system set up for that any more, so figured I'd try running a linux audio distro in a VM. UbuntuStudio runs fine. But the latest release of AVLinux refuses to boot, it says: > No DEFAULT or UI configuration directive found! > boot: _ Googling around shows that I need to rename isolinux to syslinux in order to fix this. However, the file system for the image is ISOFS, and there does not appear to be a way to mount it read-write in order to change it. Is there any other trick/workaround for this? Thanks. -ken

10 years, 11 months

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Linux-audio-user May 2014