These are just some notes on how I'm trying to clean up Linux support a bit to make the Focusrite Scarlett 18i8 (gen2) and 2i4 a bit easier to use.
Currently having issues getting a clean test run on upstream project. See failing history
- Filed a minor tweak to logging
Going to proceed with trying to label inputs better, make a profile for recording analog & spdif, ignoring ADAT for now
I still haven't fully worked through how GNOME sets its defaults, but my hope is to set up a policy so that these interfaces can be used for:
- default output, with volume configurable in Gnome. Mute it in gnome to get rid of system sounds, firefox, etc
- JACK apps, such as Renoise
In either case, I'd like to be able to work on music in Renoise+Reaper, without system sounds showing up in the recording
I have the mixer driver loaded during all of this. I have not tested this device without the mixer driver loaded. The alsa-scarlett-gui page shows how to do this in the prerequisites.
[172458.667696] usb 3-1: New USB device found, idVendor=1235, idProduct=8204, bcdDevice= 6.2f
[172458.667708] usb 3-1: New USB device strings: Mfr=1, Product=3, SerialNumber=2
[172458.667713] usb 3-1: Product: Scarlett 18i8 USB
[172458.667716] usb 3-1: Manufacturer: Focusrite
[172458.667720] usb 3-1: SerialNumber: 00034685
[172461.685937] usb 3-1: Focusrite Scarlett Gen 2/3 Mixer Driver enabled pid=0x8204
Here's the initial state from aplay -L . Instead of labelling things surround, I'd like them to be direct and reference the labels on the device itself.
$ aplay -L
null
Discard all samples (playback) or generate zero samples (capture)
sysdefault
Default Audio Device
pipewire
PipeWire Sound Server
default
Default ALSA Output (currently PipeWire Media Server)
sysdefault:CARD=sofhdadsp
sof-hda-dsp,
Default Audio Device
sysdefault:CARD=USB
Scarlett 18i8 USB, USB Audio
Default Audio Device
front:CARD=USB,DEV=0
Scarlett 18i8 USB, USB Audio
Front output / input
surround21:CARD=USB,DEV=0
Scarlett 18i8 USB, USB Audio
2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=USB,DEV=0
Scarlett 18i8 USB, USB Audio
4.0 Surround output to Front and Rear speakers
surround41:CARD=USB,DEV=0
Scarlett 18i8 USB, USB Audio
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=USB,DEV=0
Scarlett 18i8 USB, USB Audio
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=USB,DEV=0
Scarlett 18i8 USB, USB Audio
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=USB,DEV=0
Scarlett 18i8 USB, USB Audio
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=USB,DEV=0
Scarlett 18i8 USB, USB Audio
IEC958 (S/PDIF) Digital Audio Output
QJackCtl does not have helpful labels for any pins:
Here's the routing I set up for basic use in alsa-scarlett-gui
It was based off the "Direct" mapping, except I mapped PCM 1 and 2 to both analog out 1 & 2, as well as 3 & 4.
In the alsa-scarlett-gui app, the labels are accurate, but the outputs were a bit confusing.
The output labels seem to be:
- Analogue 1, 2 - monitor out
- Analogue 3, 4 - Headphone 1
- Analogue 5, 6 - Headphone 2
- S/PDIF 1, 2 - SPDIF
These do not correspond to the Alsa device labels yet. Those are all AUX# . UCM should be able to fix that up.
Bus 003 Device 005: ID 1235:8200 Focusrite-Novation Scarlett 2i4 USB
aplay -L output
$ aplay -L
null
Discard all samples (playback) or generate zero samples (capture)
pipewire
PipeWire Sound Server
default
Default ALSA Output (currently PipeWire Media Server)
sysdefault:CARD=sofhdadsp
sof-hda-dsp,
Default Audio Device
sysdefault:CARD=USB
Scarlett 2i4 USB, USB Audio
Default Audio Device
front:CARD=USB,DEV=0
Scarlett 2i4 USB, USB Audio
Front output / input
surround21:CARD=USB,DEV=0
Scarlett 2i4 USB, USB Audio
2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=USB,DEV=0
Scarlett 2i4 USB, USB Audio
4.0 Surround output to Front and Rear speakers
surround41:CARD=USB,DEV=0
Scarlett 2i4 USB, USB Audio
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=USB,DEV=0
Scarlett 2i4 USB, USB Audio
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=USB,DEV=0
Scarlett 2i4 USB, USB Audio
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=USB,DEV=0
Scarlett 2i4 USB, USB Audio
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=USB,DEV=0
Scarlett 2i4 USB, USB Audio
IEC958 (S/PDIF) Digital Audio Output
This shows up clean with each pair of outputs in pavucontrol, qjackctl, GNOME Settings.
$ alsaucm -c hw:1 dump text
Verb.HiFi {
Comment Default
Device.Line1 {
Comment "Line 1-2"
Values {
CaptureCTL "_ucm0001.hw:USB"
PlaybackCTL "_ucm0001.hw:USB"
PlaybackChannels 2
PlaybackMixer "_ucm0001.default:USB"
PlaybackMixerElem "Line 1-2"
PlaybackPCM "_ucm0001.scarlett2i4_stereo_out:USB,0,0,1"
PlaybackPriority 200
}
}
Device.Line2 {
Comment "Line 3-4"
Values {
CaptureCTL "_ucm0001.hw:USB"
PlaybackCTL "_ucm0001.hw:USB"
PlaybackChannels 2
PlaybackMixer "_ucm0001.default:USB"
PlaybackMixerElem "Line 3-4"
PlaybackPCM "_ucm0001.scarlett2i4_stereo_out:USB,0,2,3"
PlaybackPriority 100
}
}
Device.Mic1 {
Comment "Input 1"
Values {
CaptureCTL "_ucm0001.hw:USB"
CaptureChannels 1
CaptureMixer "_ucm0001.default:USB"
CaptureMixerElem "Input 1"
CapturePCM "_ucm0001.scarlett2i4_mono_in:USB,0,0"
CapturePriority 200
PlaybackCTL "_ucm0001.hw:USB"
}
}
Device.Mic2 {
Comment "Input 2"
Values {
CaptureCTL "_ucm0001.hw:USB"
CaptureChannels 1
CaptureMixer "_ucm0001.default:USB"
CaptureMixerElem "Input 2"
CapturePCM "_ucm0001.scarlett2i4_mono_in:USB,0,1"
CapturePriority 100
PlaybackCTL "_ucm0001.hw:USB"
}
}
}
Verb.Direct {
Comment "Direct Scarlett 2i4 USB"
Device.Direct {
Comment "Direct Scarlett 2i4 USB"
Values {
CaptureCTL "_ucm0001.hw:USB"
CaptureChannels 2
CapturePCM "_ucm0001.hw:USB"
CapturePriority 1000
PlaybackCTL "_ucm0001.hw:USB"
PlaybackChannels 4
PlaybackPCM "_ucm0001.hw:USB"
PlaybackPriority 1000
}
}
}
