====== focusrite scarlett ======

===== General =====

The Focusrite Scarlett [[http://us.focusrite.com/usb-audio-interfaces/scarlett-2i2|2i2]] and [[http://global.focusrite.com/usb-audio-interfaces/scarlett-2i4|2i4]] both have 2x combo XLR and TRS inputs and are USB 2.x bus powered. The 2i4 has 2 extra outputs, MIDI and extra hardware controls. The range also includes 8i6, 18i6 and 18i20. At least some are described as class compliant.

===== Support =====

The 2i2 and 2i4 are both confirmed to work well with Linux, ALSA and JACK. Using the correct settings, you can achieve near 1ms latency with no xruns using 96Khz or 48Khz 24 bit audio with the Scarlett 2i4.

===== JACK notes =====

The following outlines how I discovered the optimal JACK settings for tracking with minimal latency and no xruns using a Scarlett 2i4:

TEST PROCEDURE

Record approx 1 minute of random sound from both XLR inputs to two separate (qtractor, in this case) tracks simultaneously, play them back then check for xruns. For the settings listed below, I was able to complete the recording test procedure with no xruns. The latency is as reported by Cadence.

TEST PLATFORM

Samsung R700 laptop, 4GB RAM + 64GB SSD running KXStudio 12.04.1 recording with qtractor 0.5.7. No synth or FX plugins nor Flash-using browser tabs open to cause xruns.

SETTINGS AND RESULTS

Frequency Buffer Periods Latency

96000 128 3 1.3ms

48000 64 3 1.3ms

===== References =====

  * [[http://linuxaudio.org/mailarchive/lau/2012/4/30/190034|LAU]] talks about the 18i6, saying it 'works', but Linux cannot control the internal mixer.
  * [[https://www.linuxmusicians.com/viewtopic.php?f=6&t=10142|LM forum]] Discussion about using the 2i4 under Linux and the source of the test data above
  * [[http://ardour.org/node/5751|Ardour forum]] says Scarlett 18i6 works on Linux with Alsa 1.0.25. Also includes a mixer
  * [[http://focusritedevelopmentteam.wordpress.com/2012/04/23/linux-and-focusrite-novation-products/|Focusrite developer blog]] on Linux

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