Linux-audio-dev

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7516 discussions

Building 'rhumba box', need square inches of ports data.

by Gene Heskett

Greetings; I'm building a rhumba box not exactly like anything I've been able to google up on the net. But I saw one a week ago that I thought worked very well as an acoustic standup bass substitute when it was close miked. My boxes panels are 5.2mm birch plywood, with double rabbeted cherry glue strips, and except for the sound port holes in the front panel, will be air sealed for best resonance. Total capacity then is 3.535 cu feet. My question is, given that the port holes will be a larger one in the dead center of the front panel, and two smaller ones flanking it, splitting the space so the smaller ones will be centered on 1/2 the distance from the center point of the center hole, sort of a | o 0 o | where the vertical lines are the ends of the box by its longest measure. Is there a formula for lowest frequency vs cubic feet that is commonly used to determine the sizes of these 'sound' portholes? Thanks all. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Yes, but every time I try to see things your way, I get a headache.

16 years, 6 months

Utility to read SMPTE LTC "audio" time-code

by Pau Arumí

Hi all, I'm facing the need of converting SMPTE LTC time-code* (encoded in an audio stream) into MTC timecode, to then route to other applications. Does anybody know a Linux application for that, or a library to decode that audio? Any advice will be appreciated. Thanks, P * http://www.philrees.co.uk/articles/timecode.htm#wave

16 years, 6 months

LAC2009 countdown

by Fons Adriaensen

Hello all, *** Latest news from Parma *** Joern N. has been here the past few days to get the streaming running and things look really good. We should have high-resolution and stable streaming, better than ever before. The streaming server homepage is at http://lac.stackingdwarves.net (IP 78.47.233.27, both on port 80 an 8000/tcp) There are two LAC chatrooms at irc.freenode.net: #lac2009 for discussions about the current paper/concert #lac2009-piazza for off-topic discussions and socializing. Remote participants are advised to join the first. They will then be able to take part in the Q&A session at the end of each presentation. See you soon in Parma ! -- FA & JN

16 years, 6 months

Travel from Milan Malpensa to Parma on wednesday evening

by Pieter Palmers

Hi all, I seem to have put myself in a brilliant position... My flight lands at 22:30 in Milan Malpensa airport, meaning that I can't make the last train from Milan to Parma. I have two possibilities: either stay a night in Milan and take the morning train, or rent a car in Malpensa, drive it to Parma and drop of it there the next morning. I've done the accounting for both scenario's, and the first one would come down to 100eur, while the car rental would set me back about 120 eur. Therefore I'm probably going to rent the car as it saves me a lot of hassle. But before booking it, I'm wondering if there are other people that might have the same issue. If so, a split fee would make things even more interesting (at least for me ;). Greets, Pieter

16 years, 6 months

[ot] Electrical Plugs in Italy

by Steven Yi

Hi All, Sort of off topic but I was having a hard time figuring this out: will electrical plugs that work other parts of Europe work in Italy as well? I am thinking the two circular prongs adapter. I have some adapters for when I was in Poland and Germany, but looking online it seemed like the adapter is slightly different in Italy but wasn't quite sure if the adapter I have will fit. Thanks! steven

16 years, 6 months

Re: [LAD] audio recording through pipe using mplayer and sox

by Kjetil S. Matheussen

Arnold Obdeijn: > > Hi all, > > I am using mplayer, sox and tee to capture streaming internet radio > and send it both to an audio recognition program and to a file > (recording). > This is how I do it: > > mplayer -playlist {url} -nocache -af volnorm -msglevel all=1 -nolirc > -vc dummy -vo null -ao pcm:file={$fifo1} & > I don't know if it will help or work, but how about using -dumpstream <file> instead of -ao pcm:file=<file> ? I think there's more buffering with -dumpstream than -ao pcm: ...

16 years, 7 months

qt and jack

by Gregorio Canelos

Greetings, I am trying to a connect a bare bones Qt-based client to the JACK audio server , and I am running into a strange run-time error. I recently posted my question on the Qt-Interest list but have had no luck. Maybe someone on this list would be kind enough to help... my Setup is: -Fedora 10 - 2.6.26.8-1.rt16.1.fc10.ccrma.i686.rt #1 SMP PREEMPT RT Tue Feb 17 15:48:24 EST 2009 i686 i686 i386 GNU/Linux -Qt 4.50 (for Linux/X11) -Jack audio connection kit The .cpp files which cause this error are here: ****************** #include <QApplication> #include "MainWindow.h" int main(int argc, char *argv[]) { QApplication app(argc, argv); MainWindow mainWindow; mainWindow.show(); return app.exec(); } ********************* #include "MainWindow.h" MainWindow::MainWindow() { QPushButton * b1 = new QPushButton("HELLO BUTTON",this); audioEngine = new AudioEngine(); audioEngine->run(); } MainWindow::~MainWindow() { } ********************** #include "AudioEngine.h" using namespace std; static int process(jack_nframes_t nframes, void *pvArg) { AudioEngine * pAudioEngine = static_cast<AudioEngine *> (pvArg); return pAudioEngine->audioEngineProcess(nframes); } int AudioEngine::audioEngineProcess(jack_nframes_t nframes) { currFrame = nframes; return 0; } AudioEngine::AudioEngine() { } AudioEngine::~AudioEngine() { } void AudioEngine::run() { const char * client_name = "Template Player"; jack_options_t options = JackNullOption; jack_status_t status; // open a client connection to the JACK server client = jack_client_open(client_name, options, &status); if (client == NULL) { fprintf(stderr, "jack_client_open() failed, status = 0x%2.0x\n", status); if (status & JackServerFailed) { fprintf(stderr, "Unable to connect to JACK server\n"); } exit(1); } if (status & JackServerStarted) fprintf(stderr, "JACK server started\n"); if (status & JackNameNotUnique) { client_name = jack_get_client_name(client); fprintf(stderr, "unique name `%s' assigned\n", client_name); } jack_set_process_callback(client, process, 0); // jack_on_shutdown(client, jack_shutdown, 0); //register the client ports input_port = jack_port_register(client, "input", JACK_DEFAULT_AUDIO_TYPE, JackPortIsInput, 0); output_port = jack_port_register(client, "output", JACK_DEFAULT_AUDIO_TYPE, JackPortIsOutput, 0); if ((input_port == NULL) || (output_port == NULL)) { fprintf(stderr, "no more JACK ports available\n"); exit(1); } jack_activate(client); } ************************* Everything compiles , but I am getting the following run-time error: /usr/libexec/<unknown>: No such file or directory. Cannot access memory at address 0x7 Cannot access memory at address 0x7 Not sure what this means... I have registered a callback function with the JACK daemon and whenever I try to access the member variable currFrame from within the callback function I get that error. Has anyone seen this error before? -Thank You!

16 years, 7 months

lv2 sampleRate PortProperty seems not to work

by Renato Fabbri

turtle rdf here: http://svn.assembla.com/svn/audioexperiments/lv2plugs/filtro-notch/filtro-n… if you go like: svn co http://svn.assembla.com/svn/audioexperiments/lv2plugs/filtro-notch make install freq control is displaying only the fractions of the current sample rate, not the fraction times the sample rate, that is, its actual frequency as it is supposed to. tested in ingen and ardour. i found this same problem reported as an ardour bug report ( http://tracker.ardour.org/view.php?id=2611), but since i got the same behavior in Ingen i dont know what to do. any idea?

16 years, 7 months

jack_midi in jackd and jackdmp

by hermann meyer

Hi to all Thats my first post to the dev list, first I wont to say hello, and sorry for my bad english. I try to do my best to make it readable for you. So,. . I try to build a jack_midi output port and I get the stuff working with jackd(1). But my test's with jackdmp end up with crash's (segfaults). I realise that's because the needed buffer recived from jack_port_get_buffer(midi_output_ports, nframes) is == 0 when I run jackdmp-1.9.2. jackd gives me a buffer from 480. I 'am only be able to protect the port for crash's but I can't figure out what I make wrong. I try and I try and I try, but I can't get now . . . It would be realy great if someone from the list here is willing to have a lock at my source and give me a hint to drive me in the right direction. My (uggly) sources are here : http://apps.sourceforge.net/trac/guitarix/browser/trunk/src/main.cpp midi_process callback start's at line 233 regards hermann

16 years, 7 months

basic in-game audio synthesis api?

by james morris

Hi, I'm wanting to use basic synthesis techniques such as ADSRs LFOs hi/lo pass filters, echo, and reverb to generate some kind of ambient sound scape using pre-recorded audio clips, for a game I'm working on. Are there any libraries around to help make this a bit easier than coding it all using SDL_mixer? I'm not keen for a game to have audio, to depend on JACK or LADSPA plugins. Cheers, James

16 years, 7 months

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Linux-audio-dev