[arm-allstar] BBB URI USB-HUB Distorted Audio

[Randy Neals]

I've been experiencing a distorted audio problem while setting up a BBB
with powered USB-HUB, DMK URI, and USB Keyboard.

The audio distortion is noticeable on audio from the node. (transmit audio)
To eliminate/isolate the issue I swapped out the URI for a SYBA USB Audio
FOB and PC speakers.
Still the same background hum/distortion. So that eliminated RF
interference, ground loops, the URI and the radio.

Through further elimination, I have identified that when my USB keyboard is
connected to the USB HUB, the hum/distortion is louder. (URI through USB
HUB to BBB, no Keyboard)

And then have compared the audio when not using a USB hub at all, and I
think there is a further improvement in audio, although not as major as
when the keyboard is /is-not connected.

My next troubleshooting step is to swap out the keyboard, and then swap out
the USB HUB.

The USB Hub I'm using is an AmazonBasics 4 Port USB 3.0 Hub with 5V/2.5A
power adapter

   - Package includes: 1 USB 3.0 4 Port Hub / 1 5V/2.5A Power Adapter / 1
   built in 10 inch USB 3.0 cable / 1 Owner's Manual
   - Compatible with USB 3.0 and backwards compatible with USB 2.0
   - Support Low speed (1.5 Mbps)/ Full speed (12 Mbps)/High speed (480
   Mbps)/ Super speed (5 Gbps)
   - Support auto switching between self-power and buspower mode
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