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faq:start [2012/03/18 17:36]
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faq:start [2017/08/26 17:21] (current)
jeb_ponderworthy.com [Q: How to remove noise from recordings? How to restore old recordings (from vinyl/tape)?]
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 ====== Linux Audio User FAQ (Frequently Asked Questions) ====== ====== Linux Audio User FAQ (Frequently Asked Questions) ======
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-. 
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-. 
  
 ===== General ===== ===== General =====
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 ==== Q: How to optimize my system for audio / midi ? ==== ==== Q: How to optimize my system for audio / midi ? ====
  
-**A:​** ​<​del>​Using ​"​real-time ​kernel" and setting priorities appropriate is an important step here</​del>​. This has often been told, but according to the jackd FAQ it is simply not true! See [[http://​jackaudio.org/​realtime_vs_realtime_kernel]] +**A:​** ​For some uses, it can be helpful to run realtime (RT) kernel, but generally this isn't necessary anymore. See the following JACK FAQ entry: ​[[http://​jackaudio.org/faq/​realtime_vs_realtime_kernel.html | Do I need a realtime kernel to use realtime scheduling?]] 
-[[wiki:​real_time_info|Articles ​and more information about real time operation]].+ 
 +In Linux kernels 3.0 and later, many of the additionally required realtime patches have been incorporated as standard. For those who are recording Audio, a standard non-realtime kernel may be sufficient for your needs, and running Jack with a non realtime kernel will work fine. 
 + 
 +You need to configure your system, however, to [[http://​jackaudio.org/​faq/​linux_rt_config.html | allow JACK to use realtime scheduling]]. 
 + 
 +This wiki has some more [[wiki:​real_time_info | articles ​and general ​information]] about real time operation.
  
 +Those who produce a lot of MIDI I/O, may want to use a Linux kernel with non-standard timer interrupt frequency (aka "tick rate"​). The standard frequency is set at 250 Hz, and realtime kernels are generally set at 1000 Hz. You may still have to use a realtime kernel to obtain accurate MIDI playback using the higher timing setting.
 ==== Q: Some of my applications sound a (half)tone too high/low, have a wrong pitch ? ==== ==== Q: Some of my applications sound a (half)tone too high/low, have a wrong pitch ? ====
 **A:** It's likely, that the sample-rate of the programs you're using doesn'​t match. **A:** It's likely, that the sample-rate of the programs you're using doesn'​t match.
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-==== Q: How to remove noise ? How to restore old recordings (from vinyl/tape) ? ====+==== Q: How to remove noise from recordings? How to restore old recordings (from vinyl/​tape)?​ ====
 Some noises can be removed by surpressing specific frequencies,​ by applying EQs or Filters. Some noises can be removed by surpressing specific frequencies,​ by applying EQs or Filters.
 Audiofile editors as audacity and rezound offer different solutions for noise removal. Audiofile editors as audacity and rezound offer different solutions for noise removal.
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   * [[http://​en.wikipedia.org/​wiki/​Audio_restoration| wikipedia - Audio restoration]]   * [[http://​en.wikipedia.org/​wiki/​Audio_restoration| wikipedia - Audio restoration]]
   * [[http://​wiki.librivox.org/​index.php/​Detailed_Audacity_Noise_Removal| librivox wiki - Detailed: Noise removal with Audacity]]   * [[http://​wiki.librivox.org/​index.php/​Detailed_Audacity_Noise_Removal| librivox wiki - Detailed: Noise removal with Audacity]]
 +  * [[http://​www.cedaraudio.com/​| CedarAudio Company ]] - with some tech. info
 **Applications** **Applications**
   * [[http://​gwc.sourceforge.net/​| The Gnome Wave Cleaner Project]]   * [[http://​gwc.sourceforge.net/​| The Gnome Wave Cleaner Project]]
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   * [[http://​www.muenchen-surf.de/​mpaar/​| "​Declick 2000" plugin - not open source, but priceless]]   * [[http://​www.muenchen-surf.de/​mpaar/​| "​Declick 2000" plugin - not open source, but priceless]]
  
 +==== Q: How to eliminate noise from live production? ====
 +Live noise has many causes, including ground-loops,​ and other equipment near and far injecting static of many kinds. ​ This includes including weak but audio-active USB signals, PC fan noise, firewire, et cetera, into powerline, ground, and thence into the system. ​ There are many approaches to this, and often more than one approach is needed.
  
 +**Related articles** 
 +  * [[http://​www.audioholics.com/​home-theater-connection/​ground-loops-eliminating-system-hum-and-buzz|Ground Loops - Eliminating System Hum and Buzz]] 
 +  * [[http://​lsn.ponderworthy.com/​doku.php/​cleaning_the_tone|Cleaning the Tone]]
  
 ==== Q: What about timers and timing ? ==== ==== Q: What about timers and timing ? ====
-Modern PCs provide good hardware timing sources. +For moderate to new hardware, TSC is the best hardware timing sources. ​ Old hardware may have timing issues with multi-core CPU where HPET (high-precision-event-timer) is preferable.
-One of it is the RTC (real-time-clock). Another one is the HPET (high-precision-event-timer), which is preferable ​due to higher accuracy.+
 Then there is a software layer (in the kernel) to make available the hw-timers to the applications,​ through different interfaces. Then there is a software layer (in the kernel) to make available the hw-timers to the applications,​ through different interfaces.
 One example is the usual system-timer. One example is the usual system-timer.
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 (see: priority settings, rtirq). (see: priority settings, rtirq).
  
-**How to know, if a HPET (hardware) is available?​**+**How to know, if a TSC / HPET (hardware) is available?​** 
 +  dmesg | grep -i tsc
   dmesg | grep -i hpet   dmesg | grep -i hpet
  
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   cat /​proc/​asound/​timers   cat /​proc/​asound/​timers
  
-**Related Kernel Options ​**+**How to config kernel for HPET?**
 <​code>​ <​code>​
 # cat .config | grep -i hpet # cat .config | grep -i hpet
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 Related Articles: Related Articles:
 [[http://​kerneltrap.org/​node/​6750| Article at kerneltrap.org]] [[http://​kerneltrap.org/​node/​6750| Article at kerneltrap.org]]
 +[[http://​btorpey.github.io/​blog/​2014/​02/​18/​clock-sources-in-linux/​]]
  
  
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 **A:** A buffer is not filled in time for the requesting software to use it. Sound data does not arrive fast enough so that the requesting software has a continuous stream of data, in other words, the requesting software runs out of sound data. This is because some part of the system is not fast enough to keep up. **A:** A buffer is not filled in time for the requesting software to use it. Sound data does not arrive fast enough so that the requesting software has a continuous stream of data, in other words, the requesting software runs out of sound data. This is because some part of the system is not fast enough to keep up.
 +
 +An obvious fix for this is increasing the period size. If you're running jack with 128, for example, and you're getting regular X-runs, then increasing the size to 256 may help immediately,​ and solve the problem.
 +
  
 ===== MIDI ===== ===== MIDI =====
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 ==== Q: Is it possible to run VST plugins on Linux? ==== ==== Q: Is it possible to run VST plugins on Linux? ====
-**A:​** ​Yes, there are different solutions:​ +**A:​** ​First one has to distinguish between ​**native** Linux VST plug-ins and VST plugins built for other operating system ​(usually Windows)There is a growing number of native Linux pluginswhich are available in VST format ​(see "​Further resources"​ below) and an also growing number of host software ​for Linux supports native Linux VST plugins ​(see list below)Also there are some hosts or additional tools, which allow to run Windows VST plugins on Linux.
-  ​[[http://​www.joebutton.co.uk/​fst/​| fst-vst ]] +
-  ​[[http://​www.breakfastquay.com/​dssi-vst/​| dssi-vst ]] +
-  ​wine with jack driver and a windows vst-host +
-  ​wine with wine-asio to jack driver ​and a windows vst-host ​(see: [[http://​wiki.jacklab.net/​index.php/​WineAsio_guide| WineAsio Guide]][[http://​people.jacklab.net/​edogawa/​files/​wineasio/​| wineasio download]], [[http://​proaudio.tuxfamily.org/​wiki/​index.php?​title=ASIO_with_Wineasio| Gentoo wineasio info]] +
-  * linux-native vst pluins ​(only availabe ​for open-sourced VSTs that compile on linux) ​(see: [[http://​www.anticore.org/​jucetice/?​page_id=4|Jost]] )+
  
 +Windows VST plugins often come as two versions built for either 32-bit or 64-bit platforms. Some of the aforementioned tools only support 32-bit plugins, some both versions.
  
-**List of windows ​vst-hosts:​**+If a Windows VST plugin doesn'​t work with any of the tools listed below, it is also possible to run a Windows VST host program under Linux via Wine and route its audio output to JACK (with or without WineASIO). 
 + 
 +**Note:** Instead ​of VST, you may prefer to use open plugin technologies like [[apps:​categories:​LV2 | LV2]], [[apps:​all:​LADSPA]],​ and [[apps:​all:​DSSI]]. 
 + 
 +**Linux VST hosts:** 
 + 
 +Open Source: 
 + 
 +  * [[http://​ardour.org | Ardour]] 
 +  * [[http://​www.audacityteam.org/​ | Audacity]] 
 +  * [[http://​kxstudio.linuxaudio.org/​Applications:​Carla | Carla]] 
 +  * [[http://​www.anticore.org/​jucetice/?​page_id=4 | Jost]] 
 +  * [[https://​lmms.io/​ | LMMS]] 
 +  * [[http://​www.muse-sequencer.org/​ | Muse Sequencer]] 
 +  * [[http://​qtractor.sourceforge.net/​ | Qtractor]] 
 +  * [[http://​users.notam02.no/​~kjetism/​radium/​ | Radium]] 
 + 
 +Proprietary:​ 
 + 
 +  * [[http://​www.bitwig.com/​ | Bitwig]] 
 +  * [[http://​energy-xt.com/​ | energyXT]] 
 +  * [[http://​www.renoise.com/ ​ | Renoise]] 
 +  * [[http://​tracktion.com | Tracktion]] 
 + 
 +**Note:** Some Linux plugin hosts only provide VST support, if you enable it at compile time with appropriate options. 
 + 
 + 
 +**Linux-Hosts with Windows VST support:​** 
 + 
 +  * [[http://​kxstudio.linuxaudio.org/​Applications:​Carla | Carla]] 
 +  * [[http://​www.breakfastquay.com/​dssi-vst/| dssi-vst]] 
 +  * [[http://​www.joebutton.co.uk/​fst/​| fst-vst]] 
 + 
 +**Windows VST hosts:** 
 + 
 +  * [[http://​www.reaper.fm/​ | REAPER]]
   * [[http://​www.hermannseib.com/​|VSTHost and SAVIHost by Hermann Seib (source available !)]]   * [[http://​www.hermannseib.com/​|VSTHost and SAVIHost by Hermann Seib (source available !)]]
-  * [[http://​www.dontcrack.com/freeware/​downloads.php/​id/​4228/​software/​MiniHost/​| MiniHost by Tobybear]] +  * [[http://​www.tobybear.de/files.html | MiniHost by Tobybear]] 
-  * [[http://www.dontcrack.com/freeware/​downloads.php/​id/​4076/​software/​MissWatson/​MissWatson ​(command-line) ​]]+  * [[http://teragonaudio.com/MrsWatson ​MrsWatson]] ​(command-line)
   * [[http://​www.kreatives.org/​kristal/​|KRISTAL Audio Engine by Matthias Juwan (free for non-commercial) ]]   * [[http://​www.kreatives.org/​kristal/​|KRISTAL Audio Engine by Matthias Juwan (free for non-commercial) ]]
  
-**List of linux vst-hosts:​** 
-  * [[http://​www.anticore.org/​jucetice/?​page_id=4| Jost linux native VST-Host ]] 
-  * Note: Some linux-apps can run vst plugins, if they are being compiled with appropriate options. 
  
 +**Running Windows VST hosts on Linux**
 +
 +  * Using Wine with its ALSA driver (optionally [[http://​gamesplusone.com/​alsa_to_jack.html | forwarding Wine's ALSA output to JACK]]).
 +  * Using Wine with WineASIO to JACK driver:
 +    * [[http://​wineasio.sourceforge.net/​ | WineASIO homepage]]
 +    * [[https://​lkubuntu.wordpress.com/​2014/​01/​09/​how-to-set-up-wineasio/​ | How to setup WineASIO]] (Ubuntu and Arch Linux)
 +    * [[http://​proaudio.tuxfamily.org/​wiki/​index.php?​title=ASIO_with_Wineasio| Gentoo WineASIO info]]
  
-**Related sites:** 
-  * [[http://​quicktoots.linuxaudio.org/​toots/​vst-plugins/​]] - a more detailed introduction 
-  * [[http://​ladspavst.linuxaudio.org/​]] - Linux Compatibility of Plugins 
  
-**Note:** Instead of VST, you will soon prefere to use **Linux plugin technologie** :-) [[apps:​all:​LADSPA]],​ [[apps:​all:​DSSI]] and [[apps:​categories:​LV2]]+**Further resources:**
  
 +  * [[http://​linux-sound.org/​linux-vst-plugins.html]] - VST/VSTi Plugins For Linux
 +  * [[http://​quicktoots.linuxaudio.org/​toots/​vst-plugins/​]] - a more detailed introduction (**Deprecated** page)
  
  
 {{tag>​howtos_and_faqs}} {{tag>​howtos_and_faqs}}
faq/start.1332088567.txt.gz · Last modified: 2012/03/18 17:36 by root