MOTU UltraLite-mk5 and Linux on Raspberry Pi 4: noise on unused channels

[grizaudio (Stephen)]

Roon Core Machine

Roon Rock NUC, Or Win10’s 10 PC running Roon server

Networking Gear & Setup Details

Netgear Orbi.

Connected Audio Devices

Raspberry Pi 4 running RoonBridge on Ubuntu-21.0
MOTU UltraLite-mk5 running via USB to RPI4, no fixed sampling rate

Description of Issue

I have the same issue. Noise on unmuted channels 9-10… Its seems Roon is feeding this channel noise.

Channel 1-8 work perfectly, no issues.

Motu UltraLite-mk5

John, do you get noise on unused channels with wind10? I suspect not? But would like to confirm. Confirmed - no noise with W10. The MOTU is a prosumer audio card, and runs at a fixed rate by design. This applies in every context irrespective of the host device operating system. EDIT: It appears I was misinformed and this is incorrect. The UL5 does adjust its sample rate as @Grizzly_Bear reported later in this thread I run at 192kHz and it sounds good whatever the original source rate is.…

I tried using Roon’s mix to “show all” channels and route left and right to Motu outputs 9 and 10.
However noise is still present, and then nothing plays at all. This occurs using Win10 or a Linux Endpoint.

Its worth noting, channel 9-10 are free of noise using Win10/Motu Asio driver.