USB Audio almost working – what am I missing?

viragored · 7 Jan 2021, 05:58

Raspberry Pi 3B with "Official" power supply, no overclocking
Installed Retropie 4.7.1 (RPI2/3) direct from Raspberry Pi Imager
Linux Kernel vn = 5.4.72-v7+

Connected USB devices are

Keyboard (when needed)
SoundBlaster “Digital Music LX” external sound device (USB powered, plays through stereo amplifier)
Joystick game controller (homemade based on “Dragonrise Inc. Generic USB Joystick” encoder)
Video output is HDMI into VGA converter, no headphone plugged in to the Pi

I followed https://retropie.org.uk/docs/Sound-Issues/#using-a-usb-audio-device

Step 1: Edited config.txt to include dtparam=audio=off and rebooted
Step 2: Chose "Audio Card" 'default' in emulationstation
Step 3: Chose "Audio Device" (ie "mixer")
Starting any game shows a list of alsa lib error messages, and no sound

I couldn't work out the steps (at the end of the "Sound Issues" page) to add a custom audio card to es_systems.cfg, I don't know enough to work out what "the name of the audio card" actually is nor which .cfg file to edit.
One link from near the bottom of the “Sound Issues” page says to use this command to find the “index number” of my USB output device:

#code block 
pi@retropie:~ $ cat /proc/asound/modules
 1 snd_usb_audio

It looks to me like I need the usb index to be 0
This page had some clues: https://retropie.org.uk/forum/topic/26434/usb-audio-broke-after-latest-updates/2?_=1625115045266
I found this page which addresses index numbers - https://www.raspberrypi-spy.co.uk/2019/06/using-a-usb-audio-device-with-the-raspberry-pi/

I edited /usr/share/alsa/alsa.conf to change these two lines from 0 to 1:

#edit
	defaults.ctl.card 1
	defaults.pcm.card 1

Almost there! Now I’ve got some sound! – EmulationStation menu makes clicks, and a sample game makes the right noises.
BUT: some things are missing which I guess are related to disabling the on-board audio. Can anyone point me to the best way to make the rest work? The configuration controls are not working, here are the details.

# Main Menu - Sound Settings
	System Volume always shows 0% (but can be adjusted before being forgotten again)
	Audio Card - Default
	Audio Device - PCM
	Navigation Sounds - On
	Enable video audio - On
	OMX player device – I’ve tried them all!

# RetroPie Configuration - Audio:
	Error message "Iv10 (etc...) failed to find mixer elements"
	Pop-up window shows "On-board audio disabled or not present" "OK" is the only choice

Here are the relevant system outputs from Linux

# code block
pi@retropie:~ lsusb
Bus 001 Device 004: ID 0079:0006 DragonRise Inc. PC TWIN SHOCK Gamepad
Bus 001 Device 005: ID 041e:3015 Creative Technology, Ltd Sound Blaster Digital Music LX
Bus 001 Device 007: ID 0c45:7300 Microdia *(my keyboard)*
Bus 001 Device 006: ID 0424:7800 Standard Microsystems Corp.
Bus 001 Device 003: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 002: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

# code block
pi@retropie:~ $ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 1: Audio [USB Audio], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

# code block
pi@retropie:~ $ aplay -L
null
    Discard all samples (playback) or generate zero samples (capture)
default:CARD=Audio
    USB Audio, USB Audio
    Default Audio Device
sysdefault:CARD=Audio
    USB Audio, USB Audio
    Default Audio Device
front:CARD=Audio,DEV=0
    USB Audio, USB Audio
    Front speakers
surround21:CARD=Audio,DEV=0
    USB Audio, USB Audio
    2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=Audio,DEV=0
    USB Audio, USB Audio
    4.0 Surround output to Front and Rear speakers
surround41:CARD=Audio,DEV=0
    USB Audio, USB Audio
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=Audio,DEV=0
    USB Audio, USB Audio
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=Audio,DEV=0
    USB Audio, USB Audio
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=Audio,DEV=0
    USB Audio, USB Audio
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=Audio,DEV=0
    USB Audio, USB Audio
    IEC958 (S/PDIF) Digital Audio Output
dmix:CARD=Audio,DEV=0
    USB Audio, USB Audio
    Direct sample mixing device
dsnoop:CARD=Audio,DEV=0
    USB Audio, USB Audio
    Direct sample snooping device
hw:CARD=Audio,DEV=0
    USB Audio, USB Audio
    Direct hardware device without any conversions
plughw:CARD=Audio,DEV=0
    USB Audio, USB Audio
    Hardware device with all software conversions

Any help will be most welcome!
PS: I'm sorry I don't know how to control the colours in the "code blocks", it's the first time I've ever come across such things.

viragored · 1 Jul 2021, 08:16

@viragored Update:
alsamixer is opening from the command line, showing the volume setting for the USB card, which is the only available device.
But I can't reach alsamixer from the RetroPie configuration menu - details in the first post.

mitu · 1 Jul 2021, 10:51

@viragored What's the name of the mixer, shown in alsamixer's screen (top-left) ? This is what you should set as 'AudioDevice' in EmulationStation.

viragored · 2 Jul 2021, 05:03

@mitu Thanks a lot for your reply.
Alsamixer shows this at the top left of its screen:

#Clip from Alsamixer
Card: USB Audio  
Chip: USB Mixer 
View: F3:[Playback] F4: Capture  F5: All  
Item: Speaker [dB gain: -3.81, -3.81]

The options that EmulationStation offers for Audio Device are:

PCM (my current selection)
HDMI
Headphones
Speaker
Master
Digital
Analogue
("USB Audio" is not there!)

The options that alsamixer offers with f6 are:

# alsamixer options
- (default)
1 USB Audio
  enter device name...

Any further suggestions will be most helpful :-)

mitu · 2 Jul 2021, 05:52

@viragored said in USB Audio almost working – what am I missing?:

Chip: USB Mixer

The mixer name for your device is not in the list that ES shows. You'll need to add it manually to the configuration file - as detailed here.

viragored · 5 Jul 2021, 02:16

@mitu Thanks once more! Sadly I'm still fairly confused and haven't made any actual progress. I'm not skilled in Linux and hope I've done the right things. Games are making the right sounds, and the ES menu clicks are audible.
Here's what I've tried after spending a lot of time on the page you linked:

First: edit es_settings .cfg to include "USB Mixer", as you'd highlighted that. Then I tried "USB Audio" instead, both gave the same result.

pi@retropie:~ $ sudo nano /opt/retropie/configs/all/emulationstation/es_settings.cfg
<string name="AudioCard" value="default" />
<string name="AudioDevice" value="USB Mixer" />
# I also tried "USB Audio" in the AudioDevice line

Then I tried following the steps on the same page to "Add a Custom Audio Device (Audio Mixer)"
This is the output from the amixer command:

pi@retropie:~ $ amixer scontrols -D default
Simple mixer control 'Speaker',0
Simple mixer control 'PCM Capture Source',0
Simple mixer control 'Line',0
Simple mixer control 'Mic',0
Simple mixer control 'IEC958 In',0
Simple mixer control 'Auto Gain Control',0

I tried "Speaker" as an option in es_settings.cfg
Still no improvement or change - game sounds and menu clicks are working, the "main menu" always shows System Volume to be 0%, and there's no access to alsamixer from the RetroPie configuration menu.

When opening either a game or the configuration menu, an error message appears briefly - it's something like <date/time> Iv10: VolumeControl ::init() failed to find mixer elements.
In the RetroPie configuration menu / Audio a window box pops up saying

 "On-board audio disabled or not present"
< OK >

That's consistent with my edit to config.txt to turn off the on-board audio, as recommended on the "Sound Issues" page

dtparam=audio=off

Would my best option actually be to turn the on-board audio on again, and then find out how to make the USB audio work alongside that? Or is that even more complex and likely to be beyond me?
Sorry if this is all obvious stuff to people who are at home with Raspberry Pi and Linux - I'm trying to learn and appreciate any help I get!

mitu · 7 May 2021, 04:14

Try with:

<string name="AudioCard" value="default" />
<string name="AudioDevice" value="Speaker" />

viragored · 5 Jul 2021, 04:16

@mitu Many thanks for such a quick reply! Some progress...
I've edited es_settings.cfg as you suggested.
Game sounds and menu clicks both are working and now games open without any error message.
In "Main Menu" / "Sound Settings" the System Volume shows a true value, is adjustable and the setting is retained.

#Current Main Menu Audio settings are:
Audio Card = default
Audio Device = Speaker
OMX = Speaker

The RetroPie configuration menu / Audio also opens without an error message.
The pop-up window box still reports "On-board audio disabled etc..." but basically it's all working :-)

Thanks once again!!

mitu · 5 Jul 2021, 04:19

@viragored said in USB Audio almost working – what am I missing?:

The pop-up window box still reports "On-board audio disabled etc..." but basically it's all working :-)

That's ok, the Audio menu is meant to configure only the on-board audio, hence the message. External (USB/GPIO) sound cards are not supported.