======Hardware - Audio - Sennheiser - GSX 1000 / GSX 1200 PRO======

[[https://www.sennheiser.com/audio-amplifier-gsx-1000|Sennheiser GSX 1000 Audio Amplifier for PC and Mac]] \\
[[https://nl-nl.sennheiser.com/audio-amplifier-gsx-1200-pro|Sennheiser GSX 1200 PRO Audio Amplifier for PC and Mac]]

See [[https://sennheiser.com/gaming-downloads|Sennheiser - Gaming Downloads]] for firmware updates for the GSX series under Firmware Update Tool under Surround Dongle Downloads.


=====Reviews=====

[[https://www.techpowerup.com/reviews/Sennheiser/GSX_1000_Audio_Amplifier/|TechPowerUp - Sennheiser GSX 1000 Audio Amplifier Review]] by [[https://www.techpowerup.com/forums/members/170991/|Inle]], on Feb 7th, 2018.


====Videos====

[[https://www.youtube.com/watch?v=MGX069Zo8kE|YouTube - This Headphone Amp will Blow Gamers' Minds!!!]] by [[https://www.youtube.com/channel/UCTzLRZUgelatKZ4nyIKcAbg|HardwareCanucks]] published on 2016-12-02. \\
[[https://www.youtube.com/watch?v=7e_yVm-vcPM|YouTube - 7.1 Surround Sound - HEAR IT YOURSELF!]] by [[https://www.youtube.com/channel/UCTzLRZUgelatKZ4nyIKcAbg|HardwareCanucks]] published on 2016-12-07. \\


=====Forums=====

[[https://www.techpowerup.com/forums/threads/sennheiser-gsx-1000-audio-amplifier.240674/|TechPowerUp Forums - Reviews - Sennheiser GSX 1000 Audio Amplifier]]



=====Notes=====


====Linux=====


===With PulseAudio enabled=== 

// Tested to work on Slackware64 14.2. //

To enable the GSX to work with PulseAudio do the following:
  - Use the following command to get the card number assigned to the GSX:<code>aplay -l | grep GSX</code>
  - Example output:<code>card 3: Audio [GSX 1200 Pro Main Audio], device 0: USB Audio [USB Audio]
card 3: Audio [GSX 1200 Pro Main Audio], device 1: USB Audio [USB Audio #1]</code> // In this case the number is (card) 3. //
  - Archive the current default.pa:<code>cp -p /etc/pulse/default.pa{,.original}</code>
  - Open /etc/default.pa in a text editor.
  - Find the lines:<code> ### Automatically load driver modules depending on the hardware available
 .ifexists module-udev-detect.so</code>
  - Add the following lines BEFORE those lines:<code>
# capture device, card 4, subdevice 0.
load-module module-alsa-source device=hw:3,0
# playback device, card 4, subdevice 1, 7.1 channels.
load-module module-alsa-sink device=hw:3,1 channels=8
</code> // Change the 3 in hw:3,0 and hw:3,1 to the card number shown in the output of the aplay -l shown earlier. //

With this setup using the volume dial on the GSX will result in audio being muted instead of adjusting volume, so leave the dial alone.

Source: [[https://gist.github.com/augustocdias/4e49515da9226490226d765eb8db898d|GitHubGist - augustocdias/sennheiser.md]]


===With PulseAudio disabled===

// Tested to work on Slackware64 14.2 (with latest patches as of 2018-11-02). //

:!: This assumes the steps described on [[https://docs.slackware.com/howtos:multimedia:pulseaudio_non-default|SlackDocs - howtos » multimedia » pulseaudio_non-default]] were followed to disable and *not* remove PulseAudio. :!:

The following ~/.asoundrc content works to enable a GSX 1200 Pro as the primary audio device with 7.1 (8-channel) audio and direct mixing (dmix) so multiple applications can play sound on the GSX. It also results in a working volume dial on the GSX.

<code>pcm.!default {
	type plug
	slave.pcm "dmixer"
}

pcm.dmixer  {
 	type dmix
 	ipc_key 1024
 	slave {
		pcm "gsx1200pro"
		period_time 0
		period_size 1024
		buffer_size 4096
		rate 44100
	}
}

pcm.gsx1200pro {
	type hw
	card Audio
	device 1
	channels 8
}

ctl.dmixer {
	type hw
	card 1
}
</code>
// Based on an example taken from the Software Mixing dmix example on [[https://www.alsa-project.org/main/index.php/Asoundrc|AlsaProject - Asoundrc]]. //

This also produces correct output for speaker-test.

Speaker-test command:
<code>speaker-test -c 8 -t wav -l 1</code>

Output:
<code>
speaker-test 1.1.1

Playback device is default
Stream parameters are 48000Hz, S16_LE, 8 channels
WAV file(s)
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 2229 to 4458
Period size range from 1114 to 1115
Using max buffer size 4456
Periods = 4
was set period_size = 1114
was set buffer_size = 4458
 0 - Front Left
 6 - Front Left Center
 2 - Front Center
 7 - Front Right Center
 1 - Front Right
 5 - Side Right
 4 - Side Left
 3 - LFE
Time per period = 11.318586
</code>

The following .asoundrc content works to make the GSX 1200 Pro the default audio device, but speaker-test will only play the sound for Front Left and Front Right speakers, speaker 2-7 are shown as Unused.
<code>
defaults.pcm.!card Audio
defaults.pcm.!device 1
defaults.pcm.!ctl Audio
defaults.pcm.!channels 8
</code>
// Based on an example taken from [[https://wiki.gentoo.org/wiki/ALSA#.7E.2F.asoundrc|Gentoo Wiki - ALSA - Configuration - ~/.asoundrc]]. //