Visual looks like it's hearing a feedback loop - Music not detected

[testbughub]

Hi!

I'm trying to get this to work without a microphone, but I'm having some issues with I'm guessing is the audio source.

When I run the visualization.py script, I get a flood of error messages about ALSA and whatnot,
but I'm aweful when it comes to audio on Linux, so I have no idea where to start.
Output - Pastebin

I've edited /etc/asound.conf as instructed.

RPi 3B+ /w USB Audio Card
Confirmed working LED strip with strandtest.

pi@raspberrypi:~/dancyPi-audio-reactive-led/python/install $ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: vc4hdmi [vc4-hdmi], device 0: MAI PCM i2s-hifi-0 [MAI PCM i2s-hifi-0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: Device [USB Audio Device], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

I feel like I'm missing something. Let me know if you need any more info, and I'll reply as soon as I can.
Any help would be much appreciated!