No audio detected

[lucafossen]

Hi, I'm trying to run the no_mic version and I'm running into some issues. Here is the log:

pi@raspberrypi:~/dancyPi-audio-reactive-led/python $ sudo python3 visualization.py scroll
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
ALSA lib pcm_oss.c:377:(_snd_pcm_oss_open) Unknown field port
ALSA lib pcm_oss.c:377:(_snd_pcm_oss_open) Unknown field port
ALSA lib pcm_a52.c:823:(_snd_pcm_a52_open) a52 is only for playback
ALSA lib conf.c:5014:(snd_config_expand) Unknown parameters {AES0 0x6 AES1 0x82 AES2 0x0 AES3 0x2 CARD 0}
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM iec958:{AES0 0x6 AES1 0x82 AES2 0x0 AES3 0x2 CARD 0}
ALSA lib pcm_usb_stream.c:486:(_snd_pcm_usb_stream_open) Invalid type for card
ALSA lib pcm_usb_stream.c:486:(_snd_pcm_usb_stream_open) Invalid type for card
ALSA lib pcm_dmix.c:1043:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
ALSA lib pcm_dmix.c:1043:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
ALSA lib pcm_dmix.c:1043:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
ALSA lib pcm_dmix.c:1086:(snd_pcm_dmix_open) unable to create IPC shm instance
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
No audio input. Volume below threshold. Volume: 9.998333e-17
FPS 40 / 50
No audio input. Volume below threshold. Volume: 0.0

It then just repeats the last line about volume being 0.0 forever, with 33-36 FPS logs in between.
Is something not installed?
Thanks for any help :)

[VonHirsch]

is the no_mic version complete? (ok if it's not) I diffed it against master and I see that edit_alsa_conf() is commented out of install and edit_modules() was added. Looks like a loopback. Is some additional config needed to route properly?

[lucafossen]

is the no_mic version complete? (ok if it's not) I diffed it against master and I see that edit_alsa_conf() is commented out of install and edit_modules() was added. Looks like a loopback. Is some additional config needed to route properly?

I followed this:
https://www.easyprogramming.net/raspberrypi/audio_reactive_holiday_leds.php
it doesn't mention that edit_alsa_conf() is commented out. I'll check out what it does and see if it works!

[naztronaut]

Hey there, the no_mic version is complete, but you can consider it a version 1.0 since I still want to make it headless. The reason some things are commented out is because I'm trying to make the "mic" toggleable so that you can choose to use a mic or no mic during install or runtime. Once I have that done, I'll merge it into the master branch.

If you run the edit_alsa_conf() function in the no_mic version, the lights won't work at all because the alsa config is edited to use a different audio device that is not the virtual device. I should have mention why it was commented out in the tutorial, but in my mind, it's temporary until I get the toggle working.

The function also creates a backup of the alsa.conf file, you can restore it pretty easily.

A couple of questions for @lucafossen:

• Are you running the full version of Raspberry Pi OS?
• Did you run visualization.py in the UI?
• Can you hear audio in your bluetooth/USB speaker?
• Can you post outputs of these commands:
  • cat /proc/asound/cards
  • cat /etc/modules
  • arecord -l
  • aplay -l

Just want to make sure things were installed properly.

Others reported similar issues and sometimes, reinstalling everything from scratch helped and other times, nothing worked. I reinstalled the no_mic version probably 8-10 times between my Pi 3 and Pi 4 and I can get it to run without issues every time. I usually follow my own videos to make sure I gave proper instructions. I'll keep trying to replicate and share a fix if I can get there.

[VonHirsch]

Ok thanks for that. I'm assuming the no_mic version allows one to feed the normal pi sound output (say HDMI) to the visualization. Is that correct?

[naztronaut]

Yeah that's correct, except I can't get it to work with HDMI or the 3.5mm audio jack output. This only works with Bluetooth and USB Speakers.

It might be possible to get this to run with HDMI output with some adjustments but the 3.5mm audio jack definitely won't work because there's some hardware/software limitation with the Pi (can't use that jack with a virtual mic).

[VonHirsch]

ok thanks, i'll look into it. If I find something working for HDMI i'll report back

[explorerswb]

I seem to be having the same problem. Raspberry Pi 4B 2gb, full version of the OS, followed the install video step by step, but when I run it I get this:

pi@raspberrypi:~ $ sudo python3 dancyPi-audio-reactive-led/python/visualization.py scroll
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
ALSA lib pcm_oss.c:377:(_snd_pcm_oss_open) Unknown field port
ALSA lib pcm_oss.c:377:(_snd_pcm_oss_open) Unknown field port
ALSA lib pcm_a52.c:823:(_snd_pcm_a52_open) a52 is only for playback
ALSA lib conf.c:5014:(snd_config_expand) Unknown parameters {AES0 0x6 AES1 0x82 AES2 0x0 AES3 0x2 CARD 0}
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM iec958:{AES0 0x6 AES1 0x82 AES2 0x0 AES3 0x2 CARD 0}
ALSA lib pcm_usb_stream.c:486:(_snd_pcm_usb_stream_open) Invalid type for card
ALSA lib pcm_usb_stream.c:486:(_snd_pcm_usb_stream_open) Invalid type for card
ALSA lib pcm_dmix.c:1043:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
ALSA lib pcm_dmix.c:1043:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
ALSA lib pcm_dmix.c:1043:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
ALSA lib pcm_dmix.c:1086:(snd_pcm_dmix_open) unable to create IPC shm instance
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
No audio input. Volume below threshold. Volume: 9.996934e-17
No audio input. Volume below threshold. Volume: 0.0
No audio input. Volume below threshold. Volume: 0.0
No audio input. Volume below threshold. Volume: 0.0
No audio input. Volume below threshold. Volume: 0.0
No audio input. Volume below threshold. Volume: 0.0
No audio input. Volume below threshold. Volume: 0.0
FPS 36 / 50
No audio input. Volume below threshold. Volume: 0.0
No audio input. Volume below threshold. Volume: 0.0
No audio input. Volume below threshold. Volume: 0.0

I'm using a Soundcore 2 Bluetooth speaker, and accessing the pi through VNC Viewer. I've tried using VLC, mplayer, and the web browser. In all cases, the sound plays through the speaker, but the lights remain unlit. My LEDs are a strand of 50 WS2811s with a separate 10A power supply, and they function properly when I run strandtest.py

More info:

pi@raspberrypi:~ $ cat /proc/asound/cards
0 [Loopback ]: Loopback - Loopback
Loopback 1
1 [b1 ]: bcm2835_hdmi - bcm2835 HDMI 1
bcm2835 HDMI 1
2 [Headphones ]: bcm2835_headphonbcm2835 Headphones - bcm2835 Headphones
bcm2835 Headphones

pi@raspberrypi:~ $ cat /etc/modules
/etc/modules: kernel modules to load at boot time.
This file contains the names of kernel modules that should be loaded
at boot time, one per line. Lines beginning with "#" are ignored.
i2c-dev
snd-aloop

pi@raspberrypi:~ $ arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: Loopback [Loopback], device 0: Loopback PCM [Loopback PCM]
Subdevices: 8/8
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3
Subdevice #4: subdevice #4
Subdevice #5: subdevice #5
Subdevice #6: subdevice #6
Subdevice #7: subdevice #7
card 0: Loopback [Loopback], device 1: Loopback PCM [Loopback PCM]
Subdevices: 8/8
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3
Subdevice #4: subdevice #4
Subdevice #5: subdevice #5
Subdevice #6: subdevice #6
Subdevice #7: subdevice #7

pi@raspberrypi:~ $ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: Loopback [Loopback], device 0: Loopback PCM [Loopback PCM]
Subdevices: 8/8
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3
Subdevice #4: subdevice #4
Subdevice #5: subdevice #5
Subdevice #6: subdevice #6
Subdevice #7: subdevice #7
card 0: Loopback [Loopback], device 1: Loopback PCM [Loopback PCM]
Subdevices: 8/8
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3
Subdevice #4: subdevice #4
Subdevice #5: subdevice #5
Subdevice #6: subdevice #6
Subdevice #7: subdevice #7
card 1: b1 [bcm2835 HDMI 1], device 0: bcm2835 HDMI 1 [bcm2835 HDMI 1]
Subdevices: 4/4
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3
card 2: Headphones [bcm2835 Headphones], device 0: bcm2835 Headphones [bcm2835 Headphones]
Subdevices: 4/4
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3

I've tried everything I can think of, including starting from scratch with a fresh OS several times. I'm at a loss at this point. Any help would be greatly appreciated!

[naztronaut]

Thanks for all the info @explorerswb! your setup looks exactly like mine (including the RPi 4 2gb).

I blocked some time this coming weekend to go through my own video and redo everything and I'm hoping I can replicate it. Maybe something changed with Raspberry Pi OS since I did this in December because the frequency of reports like this has gone up.

I'll record the set up as well and go through it from scratch.

[explorerswb]

On a whim, I downloaded both the 2020-12-02 and 2020-08-20 versions of Raspberry Pi OS Full. I didn't update anything before running the install script, and the results were the same. So if this problem is the result of a software update, it would seem to be in one of the packages downloaded by the install script.

I am also planning to try installing this on my RPi 3 B+ just to see if anything different happens, but that will have to wait for the weekend.

[VonHirsch]

Hey guys, just an update from my end - I'm trying to use this config:

"Record audio from an application while also routing the audio to an output device"
https://trac.ffmpeg.org/wiki/Capture/ALSA#Recordaudiofromanapplication

But it doesn't appear to work. I saw at least one error message in syslog which led me to update the Pi4's firmware (see here) but that didn't resolve the issue.

I'm still an alsa newbie, so I'm going to keep digging in to see what other audio mixing mechanisms are available (and working) on raspberry pi.

[lucafossen]

Hi @naztronaut , thanks for the reply.

• I am running Raspberry Pi OS (32 bit), the one that first pops up when opening the imager. I will try to replicate with the Raspberry Pi OS Full (32 bit) today.
• I ran visualization.py with sudo in the terminal.
• Yes, I can hear audio.
• Here is the output:

pi@raspberrypi:~ $ cat /proc/asound/cards
 0 [Loopback       ]: Loopback - Loopback
                      Loopback 1
 1 [b1             ]: bcm2835_hdmi - bcm2835 HDMI 1
                      bcm2835 HDMI 1
 2 [Headphones     ]: bcm2835_headphonbcm2835 Headphones - bcm2835 Headphones
                      bcm2835 Headphones
pi@raspberrypi:~ $ cat /etc/modules
# /etc/modules: kernel modules to load at boot time.
#
# This file contains the names of kernel modules that should be loaded
# at boot time, one per line. Lines beginning with "#" are ignored.

i2c-dev
pi@raspberrypi:~ $ arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: Loopback [Loopback], device 0: Loopback PCM [Loopback PCM]
  Subdevices: 8/8
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
  Subdevice #7: subdevice #7
card 0: Loopback [Loopback], device 1: Loopback PCM [Loopback PCM]
  Subdevices: 8/8
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
  Subdevice #7: subdevice #7
pi@raspberrypi:~ $ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: Loopback [Loopback], device 0: Loopback PCM [Loopback PCM]
  Subdevices: 8/8
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
  Subdevice #7: subdevice #7
card 0: Loopback [Loopback], device 1: Loopback PCM [Loopback PCM]
  Subdevices: 8/8
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
  Subdevice #7: subdevice #7
card 1: b1 [bcm2835 HDMI 1], device 0: bcm2835 HDMI 1 [bcm2835 HDMI 1]
  Subdevices: 4/4
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
card 2: Headphones [bcm2835 Headphones], device 0: bcm2835 Headphones [bcm2835 Headphones]
  Subdevices: 4/4
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
pi@raspberrypi:~ $

I appreciate the time you take to help newbies like me!

[lucafossen]

I have installed the full OS now, still getting the same issue.

• I am now running Raspberry Pi OS Full (32 bit)
• I ran visualization.py with sudo in the terminal.
• Yes, I can hear audio.
• Here is the output:

pi@raspberrypi:~/dancyPi-audio-reactive-led/python $ sudo python3 visualization.py scroll
ALSA lib pcm_dsnoop.c:638:(snd_pcm_dsnoop_open) unable to open slave
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.iec958
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
ALSA lib pcm_oss.c:377:(_snd_pcm_oss_open) Unknown field port
ALSA lib pcm_oss.c:377:(_snd_pcm_oss_open) Unknown field port
ALSA lib pcm_a52.c:823:(_snd_pcm_a52_open) a52 is only for playback
ALSA lib conf.c:5014:(snd_config_expand) Unknown parameters {AES0 0x6 AES1 0x82 AES2 0x0 AES3 0x2  CARD 0}
ALSA lib pcm.c:2565:(snd_pcm_open_noupdate) Unknown PCM iec958:{AES0 0x6 AES1 0x82 AES2 0x0 AES3 0x2  CARD 0}
ALSA lib pcm_usb_stream.c:486:(_snd_pcm_usb_stream_open) Invalid type for card
ALSA lib pcm_usb_stream.c:486:(_snd_pcm_usb_stream_open) Invalid type for card
ALSA lib pcm_dmix.c:1043:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
ALSA lib pcm_dmix.c:1043:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
ALSA lib pcm_dmix.c:1043:(snd_pcm_dmix_open) The dmix plugin supports only playback stream
ALSA lib pcm_dmix.c:1086:(snd_pcm_dmix_open) unable to create IPC shm instance
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
No audio input. Volume below threshold. Volume: 9.990389e-17
No audio input. Volume below threshold. Volume: 0.0
No audio input. Volume below threshold. Volume: 0.0
No audio input. Volume below threshold. Volume: 0.0
FPS 37 / 50
No audio input. Volume below threshold. Volume: 0.0

[VonHirsch]

@lucafossen sorry for hijacking your thread here, I considered opening a separate issue, but since it appears all of us here are cracking the same nut it made sense to keep posting on this thread. I hope you don't mind!

I was able to get dancyPi working without a mic, i'm posting the details below so @naztronaut can work this into his installer on the weekend.

First an important note about audio drivers on raspberry pi:

As of Decemeber 2020 Raspberry Pi OS now uses PulseAudio as it's primary instead instead of Alsa. This is important because all my testing has been done on a Pi4 using Raspberry Pi OS Lite headless over ssh and as far as I can tell the lite version still retains Alsa as it's primary, but if you install the desktop versions they probably include PulseAudio. I'm going to experiment with that later but for now I highly recommend you start with lite and go headless. This is the best way to narrow down any issues your having.

Also! Note that errors regarding jack server etc. are bogus and don't mean anything. They can be ignored.

Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started

Ok so here are the step-by-steps I used to get this working:

1. Load fresh version of raspbian lite on the pi 4
2. Add snd-aloop module to load at boot time (command on next step)
3. sudo echo 'snd-aloop' >> /etc/modules
4. reboot
5. run aplay -l
6. you will notice that card 0 is now the loopback device. at this point you won't get any sound bc nothing is hooked up
7. sudo apt-get install -y git
8. git clone https://github.com/naztronaut/dancyPi-audio-reactive-led.git
9. we are NOT going to use the no_mic branch. this is intentional, stay on master
10. sudo python3 dancyPi-audio-reactive-led/python/install/install.py
11. make sure "USE_GUI = False" in python/config.py
12. copy paste below config into /etc/asound.conf (replacing anything that's there) I've included tons of comments to explain what's going on.

###################################################
#  /etc/asound.conf
# This config will route (split actually) your default audio output to:
# 		1 - your speakers (pcm.output)
#		2 - your default microphone input (capture.pcm)
#
# To enable loopback channels neccessary for this:
#		sudo echo 'snd-aloop' >> /etc/modules
#		reboot
#		loopbacks will now be visible in aplay -l
#
# Loopbacks simply loopback from one to the other bi-directionally
#	e.g.
#		hw:Loopback,0,0 <--> hw:Loopback,1,0
#
# 		Anything dumped in one end will come out the other
#		By default snd-aloop creates 8 of these loopback pipes for you
#			
# Below the "Set audio pcm defaults" section will:
#		output audio by default to slave.pcm "multi"
# 		capture audio by default from slave.pcm "loopout"
#
# The "multi" slave pcm device will copy the buffer equally to "output" and "loopin"
#		output is set to whatever output card you want listed in aplay -l output
#		loopin loops back to loopout (the default capture device)
#
# To test play in one terminal:
#		aplay piano2.wav
# Record in another:
#		arecord -f S16_LE -c 2 -r 44000 audio.wav
#		aplay audio.wav (play back recording)
#
#  Good Luck
###################################################

# The "multi" slave pcm device will copy the buffer equally to "output" and "loopin"
pcm.multi {
    type route;
    slave.pcm {
        type multi;
        slaves.a.pcm "output";
        slaves.b.pcm "loopin";
        slaves.a.channels 2;
        slaves.b.channels 2;
        bindings.0.slave a;
        bindings.0.channel 0;
        bindings.1.slave a;
        bindings.1.channel 1;
        bindings.2.slave b;
        bindings.2.channel 0;
        bindings.3.slave b;
        bindings.3.channel 1;
    }

    ttable.0.0 1;	# copy source channel 0 to slave a, channel 0
    ttable.1.1 1;	# copy source channel 1 to slave a, channel 1
    ttable.0.2 1;	# copy source channel 0 to slave b, channel 0
    ttable.1.3 1;	# copy source channel 1 to slave b, channel 1
}

# Set audio pcm defaults
pcm.!default {
  type asym
   playback.pcm {
     type plug
     slave.pcm "multi"		# output audio by default to slave.pcm "multi"
   }
   capture.pcm {
     type plug
     slave.pcm "loopout"	# capture audio by default from slave.pcm "loopout"
   }
}

# This sets the default control options to use *hw* card #1
ctl.!default {
        type hw
        card 1
}

# Output Alias - set this to the desired output card from aplay -l
pcm.output {
    type hw
    card 1
}

# Loopback 0,0 alias "loopin" - anything put in here will loop back out "loopout" below
pcm.loopin {
    type plug
    slave.pcm "hw:Loopback,0,0"
}

# Loopback 1,0 alias "loopout"
pcm.loopout {
    type plug
    slave.pcm "hw:Loopback,1,0"
}

@naztronaut below is some code that might interest you. You might want to incoporate this into your installer, like maybe it could prompt them to choose? I used it to determine what input_device_index the pyaudio stream should listen to:

info = p.get_host_api_info_by_index(0)
numdevices = info.get('deviceCount')
for i in range(0, numdevices):
    if (p.get_device_info_by_host_api_device_index(0, i).get('maxInputChannels')) > 0:
        print("Input Device id ", i, " - ", p.get_device_info_by_host_api_device_index(0, i).get('name'))

To test this code you can paste it into microphone.py underneath the line "p = pyaudio.PyAudio()"

It will output something like this:

Input Device id  0  -  Loopback: PCM (hw:0,0)
Input Device id  1  -  Loopback: PCM (hw:0,1)
Input Device id  4  -  Sennheiser USB Headset: Audio (hw:3,0)
Input Device id  5  -  sysdefault
Input Device id  6  -  default

You will want to select the id corresponding to Loopback: PCM (hw:0,1) which is where the above config dumps out a copy of the default audio.

To set the input_device_index, edit microphone.py like so:

stream = p.open(format=pyaudio.paInt16,
                channels=1,
                rate=config.MIC_RATE,
                input=True,
                frames_per_buffer=frames_per_buffer,
                input_device_index=1)

With the above asound.conf and input_device_index you should be able to play sound through the default Alsa input, hear it on your output, and see it while running the visualizer against the loopback:

Terminal 1:
sudo python3 visualization.py scroll

Terminal 2:
wget http://www.kozco.com/tech/piano2.wav
aplay piano2.wav

See the comments in the asound.conf for more test commands.

If you want to use something like omxplayer, make sure you specify that it outputs to Alsa like so:

omxplayer -o alsa:default <file.mp3>

which demonstrates that any program you use must leverage the Alsa driver in order for this to work.

[naztronaut]

Amazing work @VonHirsch! I'm going to try all of this out and make necessary updates to the project.

It's interesting to read about Alsa and Pulseaudio. It's also funny how the update happened in Dec 2020. I think my installation is from the previous build so I never ran into this. And during reinstalls, the Pi Imager has just been installing a cached version of RPi OS.

Good to know.

Thanks! I'll let you know how my testing goes. Will try to do it this weekend but may need to move it to next weekend. I adopted a cat which is taking up a lot of my free time now :)

[VonHirsch]

@naztronaut thanks! Glad you like it. Oh yes don't worry about it, family and pets always come first! =)