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focusrite scarlett solo questions

Posted: Sun Mar 10, 2019 6:32 pm
by vasili
Hi all,

i am a totally unexperienced digital audio user, and i'd like to understand better a few things.

So i thought that starting with an external audio controller was a good idea, so i bought a scarlett solo. I'm using avlinux atm, and the hardware
worked out of the box. However, when i started to use all the software equipment useful to make music on linux, some things didn't work as i expected.
My questions are:

1. is it possible to use jack and scarlett solo WITHOUT pulseaudio? killing the daemon just got me to no audio output, and i think this isn't normal;
2. i think that the problem above might be related to no mixer software for the scarlett solo hardware. I mean, when i switch to scarlett's card controls
on alsamixer i can't see useful settings available.

If you need i can give any lspci lsusb or any other output.

thanks,
vasili

Re: focusrite scarlett solo questions

Posted: Sun Mar 10, 2019 7:13 pm
by khz
:welcome:
@PA Stop Pulseaudio temporarily >> https://linuxmusicians.com/viewtopic.php?p=103154#p103154
I hope that's some help.

Re: focusrite scarlett solo questions

Posted: Sun Mar 10, 2019 7:41 pm
by bluebell
vasili wrote:Hi all,

i am a totally unexperienced digital audio user, and i'd like to understand better a few things.

So i thought that starting with an external audio controller was a good idea, so i bought a scarlett solo. I'm using avlinux atm, and the hardware
worked out of the box. However, when i started to use all the software equipment useful to make music on linux, some things didn't work as i expected.
My questions are:

1. is it possible to use jack and scarlett solo WITHOUT pulseaudio? killing the daemon just got me to no audio output, and i think this isn't normal;

2. i think that the problem above might be related to no mixer software for the scarlett solo hardware. I mean, when i switch to scarlett's card controls
on alsamixer i can't see useful settings available.


Keep in mind that the interface can be owned by only one, and that should be jackd.
Pulseaudio can be configured to output to and input from jackd instead directly to and from the audio interface,

There are many ways to do this. Pulseaudio can be reconfigured at runtime. But you can do it as I did:

http://marzen.de/Holger/pulseaudio_and_jack/

The Scarlett Solo, 2i2 and 2i4 have no hardware mixer that can be controlled ba ALSA, only with the knob on the interface. But that's no disadvantage.

Re: focusrite scarlett solo questions

Posted: Sun Mar 10, 2019 7:43 pm
by Michael Willis
Yes, you should be able to use your interface without pulseaudio, but it depends on what application you are using. Any audio production software should be able to use the hardware via Jack or ALSA, but "normal" apps like games or browsers or whatnot likely won't be able to play sound without pulseaudio.

Re: focusrite scarlett solo questions

Posted: Wed Mar 13, 2019 12:00 pm
by vasili
thanks for your replies.

i am using this toolset:
musescore
linuxsampler
carla
nonsession
nonmixer
jamin
qjackctl

as soon as i stop pulse audio, the pulse sink disappears, wich is normal, but also i get no sound at all.
jack is configured to use USB:hw device in the list wich corresponds to my scarlett solo.

thanks

Re: focusrite scarlett solo questions

Posted: Wed Mar 13, 2019 3:22 pm
by bluebell
vasili wrote:thanks for your replies.

i am using this toolset:
musescore
linuxsampler
carla
nonsession
nonmixer
jamin
qjackctl

as soon as i stop pulse audio, the pulse sink disappears, wich is normal, but also i get no sound at all.
jack is configured to use USB:hw device in the list wich corresponds to my scarlett solo.

thanks


There are some programs that can output both to ALSA or JACK. If you have pulseaudio installed then ALSA-clients are redirected to pulseaudio.

So I guess your audio outputting programs use ALSA. ALSA gets redirected to pulseaudio. Pulseaudio is not running. No sound.

Configure them to use JACK.

Re: focusrite scarlett solo questions

Posted: Wed Mar 13, 2019 10:47 pm
by vasili
ok, so i've been able to hear audio output using alsa, but the signal is really really faint.
could this be the internal mixer not being correctly addressed by the alsa driver?

thanks

Re: focusrite scarlett solo questions

Posted: Thu Mar 14, 2019 6:27 am
by bluebell
vasili wrote:ok, so i've been able to hear audio output using alsa, but the signal is really really faint.
could this be the internal mixer not being correctly addressed by the alsa driver?

thanks


No, the Scarletts work fine with Linux. I have a Solo, 2i2 and 2i4.

Maybe you have to turn the big volume knob to the max and/or set the "direct monitor" switch to "off" to get more output.

I recommend that you
- setup jackd
- configure pulseaudio to output via jack (jack-sink)
- use jack in your programs (Audacity can record from and output to jack)

Re: focusrite scarlett solo questions

Posted: Thu Mar 14, 2019 12:26 pm
by Linuxmusician01
For what it's worth, I never kill PA anymore. Like @Bluebell wrote above I installed pulseaudio-module-jack (on Linux Mint) which probably is the reason I don't have to stop PA (which on most systems automatically re-spawns so problems occur again out of the blue). This little script might come in handy if you want to start/stop audio servers check some basic Midi stuff etc.

vasili wrote:I mean, when i switch to scarlett's card controls on alsamixer i can't see useful settings available.

If you start alsamixer and press F6 (select sound card) and choose your Scarlett card, then that should provide you w/ some useful controls. Does it now?

Re: focusrite scarlett solo questions

Posted: Thu Mar 14, 2019 1:12 pm
by vasili
If you start alsamixer and press F6 (select sound card) and choose your Scarlett card, then that should provide you w/ some useful controls. Does it now?


i can only see one control set to zero (00) labeled "Usb internal validity"

Maybe you have to turn the big volume knob to the max and/or set the "direct monitor" switch to "off" to get more output.


I fiddled with both, the monitor knob and the direct monitor, but nothing changes. i mean, the output volume still remains very low.
just to be clear about this, the signal that arrives on non mixer has a max value of -60...

Re: focusrite scarlett solo questions

Posted: Thu Mar 14, 2019 3:54 pm
by Linuxmusician01
vasili wrote:
If you start alsamixer and press F6 (select sound card) and choose your Scarlett card, then that should provide you w/ some useful controls. Does it now?


i can only see one control set to zero (00) labeled "Usb internal validity"

Hmmmm. What if you press F5 (= "show all controls")? Maybe somebody who has a Scarlett Solo can tel you if that's normal. Maybe the Alsa kernel module (i.e. the "driver") for the Scarlett isn't loaded properly (if at all). Strange... :?

Re: focusrite scarlett solo questions

Posted: Thu Mar 14, 2019 5:59 pm
by vasili
What if you press F5 (= "show all controls")?


pressing f5 doesn't change anything, i.e. all controls sum up to usb internal validity

Re: focusrite scarlett solo questions

Posted: Thu Mar 14, 2019 6:10 pm
by vasili
Maybe the Alsa kernel module (i.e. the "driver")


this is what uname -a gives

Code: Select all

vasili@vaccone-avl:~$ uname -a
Linux vaccone-avl 4.16.12-rt5-avl1 #12 SMP PREEMPT RT Thu Jun 14 04:35:48 EDT 2018 x86_64 GNU/Linux

Re: focusrite scarlett solo questions

Posted: Fri Mar 15, 2019 12:50 pm
by Linuxmusician01
vasili wrote:
Maybe the Alsa kernel module (i.e. the "driver")


this is what uname -a gives

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vasili@vaccone-avl:~$ uname -a
Linux vaccone-avl 4.16.12-rt5-avl1 #12 SMP PREEMPT RT Thu Jun 14 04:35:48 EDT 2018 x86_64 GNU/Linux

That command shows the kernel version that you use. It's a command to remember. To see a list of kernel modules that are loaded one uses this command:

Code: Select all

lsmod

The problem is that I don't know what the name is of the kernel module for the Scarlett Solo because I don't have one. Some googling provides me w/ the info that this is an USB audio device and that there are two versions of it: first generation and second generation. Both work in most MacOS versions and @Bluebell has one working in Linux so I assume it's class compliant. If it's class compliant it probably uses the kernel module (or "driver") called snd_usb_audio. Funny thing is that only the Focusrite 2i4 can be found as a supported Alsa device on the web (link).

I have an external USB sound device too, it's a lot like the ones from Scarlett (Behringer UMC404HD). All USB sound cards appear to use the same driver (snd_usb_audio). But they show up "a little bit funny" in alsamixer. Anyway, you can check if the snd_usb_audio is loaded w/ the following command:

Code: Select all

 lsmod | grep usb

Output should look someting like tis:

Code: Select all

Module                  Size  Used by
snd_usb_audio         155107  0
snd_usbmidi_lib        29282  1 snd_usb_audio
usblp                  22891  0
snd_hwdep              13602  3 snd_usb_audio,snd_hda_codec,snd_opl3_lib
snd_pcm               102099  5 snd_usb_audio,snd_hda_codec_hdmi,snd_hda_codec,snd_hda_intel,snd_cmipci
snd_rawmidi            30731  3 snd_usbmidi_lib,snd_mpu401_uart,snd_seq_midi
snd                    69416  27 snd_hda_codec_realtek,snd_hrtimer,snd_usb_audio,snd_hwdep,snd_timer,snd_hda_codec_hdmi,snd_pcm,snd_seq,snd_rawmidi,snd_usbmidi_lib,snd_hda_codec,snd_hda_intel,snd_mpu401_uart,snd_seq_device,snd_seq_dummy,snd_cmipci,snd_seq_midi_emul,snd_opl3_lib,snd_seq_midi
usbhid                 52659  0
hid                   106148  2 hid_generic,usbhid

Anyway, to answer the questions in your top post:
  1. Why do I not see anything useful in alsamixer?
  2. Can I use Jack and what about PulseAudio?
1. I don't see anything useful either in alsamixer for my USB audio device. One is supposed to use Jack I guess.

2. Yes, you should use Jack. If you install something like pulseaudio-module-jack (on an Ubuntu-like distro) then you do not have to kill PA to use Jack.

Do you know already how to use shell scripts? A shell script is a text file w/ commands in it that can be executed. It must be placed some where where Linux can "find it", for instance in /home/your_name/bin/. You should make the file executable and then you can run it from a terminal. I've made a script w/ some audio commands that i use often. It's called menuaudio.sh and you can find it here. Looks like this:

Code: Select all

┌─────────────────────────────────────┐
│              Midi menu              │
└─────────────────────────────────────┘
Use ↑ and ↓ keys to select and Enter
to execute.

 Jack audio daemon: start               
                  : kill               
 Check Midi       : port numbers       
                  : output             
 Check Alsa       : device/card numbers
 Pulseaudio       : start               
                  : stop               
                  : PAVUControl         
 Config file      : create/edit         
                  : delete             
                  : view               
 Help                                 
 Exit                                 

If your USB audio card is recognized properly then Qjackctl may look like this (notice the entry 404HD):
Image

Good luck! :)

Re: focusrite scarlett solo questions

Posted: Sun Mar 17, 2019 8:05 pm
by vasili
thanks everyone for your replies.

the low output volume was due to the samplefont i used for my music. changing this it greatly improved the sound output.
however, i realized i have serious issues with my toolchain, because :

- using musescore by itself, i.e. not inside the toolchain, i can make tempo and dynamics adjustments. As soon as i fire up
carla etc soumething goes wrong and the music is played back at 120bpm tempo, which is really strange.changing the tempo value
doesn't have any effect, nor using musescore's play panel;
- recovering session inside the non session manager is a pain in the ass, non mixer crashes. i cant figure out why.

maybe all these new issues, are material for a different forum, if so please point me to it.

thanks again.