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wiki:cadence_introduction [2013/06/02 15:45] – external edit 127.0.0.1wiki:cadence_introduction [2013/10/22 15:33] – [JACK Status] danboid
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 =====System Status===== =====System Status=====
  
-This lets you select the CPU Scaling Governor, a property of the Linux kernel which controls the CPU speed. In 'performance' mode, your CPU will run at full speed all the time. This mode consumes the most power but ensures the best performance and minimum CPU-related sound issues. In many cases (especially on battery powered devices) using 'ondemand' makes more sense as this ups the CPU speed when its needed but clocks it back down when the computer is idle which helps save power. //Note: to enable this option in KXStudio 12.04.1, you must first install "indicator-cpufreq" but this will be included on install in 12.04.2.//+This lets you select the CPU Scaling Governor, a property of the Linux kernel which controls the CPU speed. In 'performance' mode, your CPU will run at full speed all the time. This mode consumes the most power but ensures the best performance and minimum CPU-related sound issues. In many cases (especially on battery powered devices) using 'ondemand' makes more sense as this ups the CPU speed when its needed but clocks it back down when the computer is idle which helps save power. //Note: to enable this option in KXStudio 12.04.1, you must first install "indicator-cpufreq" but this is included by default in 12.04.3.//
  
 =====System Checks===== =====System Checks=====
  
-Current kernel is a verification that you're running a realtime or lowlatency kernel. This check will be ticked already if you installed from the KXStudio ISO as it includes a low latency kernel. The other check verifies that your user is included in the audio group. Being a member of the audio group is required for your user to run JACK in realtime mode for optimal performance. You can add your user to the audio group by running:+Current kernel is a verification that you're running a realtime or lowlatency kernel. This check will be ticked already if you installed from the KXStudio ISO as it includes a low latency kernel. The other check verifies that your user is included in the audio group. Being a member of the audio group is required for your user to run JACK in realtime mode for optimal performance and is also required to access FireWire devices.  
 + 
 +The user created during installation of KXStudio 12.04.3 is automatically added into the audio and video groups but newly created users will not be part of these groups. You can add a user to the audio group by running:
  
   sudo adduser <username> audio   sudo adduser <username> audio
  
-Replace <username> with your KXStudio user name when you run that command in a terminal. You will then need to log out and back in or reboot before your user will be recognised as being in the audio group.+Replace <username> with a KXStudio user name when you run that command in a terminal. You will then need to log out and back in or reboot before the user will be recognised as being in the audio group. Alternately, you can manage users and groups using the graphical kuser tool which is included with 12.04.3.
  
 =====JACK Status===== =====JACK Status=====
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 **DSP Load** is the current CPU load estimated by JACK. If it gets too high you may experience performance issues. **DSP Load** is the current CPU load estimated by JACK. If it gets too high you may experience performance issues.
  
-**Xruns** For JACK to operate smoothly and without drop-outs it requires that its buffers (the memory used to transport audio) provide a continuous stream of data. Whenever this data fails to arrive in time to satisfy the requests of a JACK app it causes an xrun which is often accompanied by a disruption to the sound output. The key to success with JACK is to eliminate or avoid xruns.+**Xruns** For JACK to operate smoothly and without drop-outs it requires that its buffers (the memory used to transport audio) provide a continuous stream of data. Whenever this data fails to arrive in time to satisfy the requests of a JACK app it causes an xrun which is often accompanied by a disruption to the sound output. The key to success with JACK is to eliminate (or at least minimize) xruns.
  
 **Buffer** size is measured in frames per second. It determines the latency between the audio being received by JACK and being sent to the output device. The smaller the buffer the lower the latency and, as a result, the higher the accuracy when monitoring audio for multitrack recording. 1024 is the default and is usually a safe value but smaller buffer sizes have less latency, i.e. less delay between the input and output. Try different settings to see how low you can go when recording without getting xruns. The functioning of lower size buffers depends on the power of your CPU and the specifics of your audio device. The lowest buffer most devices can handle well is 64. **Buffer** size is measured in frames per second. It determines the latency between the audio being received by JACK and being sent to the output device. The smaller the buffer the lower the latency and, as a result, the higher the accuracy when monitoring audio for multitrack recording. 1024 is the default and is usually a safe value but smaller buffer sizes have less latency, i.e. less delay between the input and output. Try different settings to see how low you can go when recording without getting xruns. The functioning of lower size buffers depends on the power of your CPU and the specifics of your audio device. The lowest buffer most devices can handle well is 64.
wiki/cadence_introduction.txt · Last modified: 2013/10/22 15:48 by danboid