MacBook Pro M1 Max - USB device interference with external synthesizers in music studio?

[Shadow Puppets]

I am running an M1 Max MacBook Pro, connected by a single cable from a Thunderbolt port to a Caldigit Thunderbolt 4 hub. That hub then connects to my monitors, interface, and USB hubs. Those USB hubs then connect to my external hardware synthesizers in my music studio. This setup works PERFECTLY, with no issues.

However, today, out of curiosity to see if I could slightly improve latency with my interface, I decided to remove the interface from the hub and connect it directly to another Thunderbolt port on the MBP. So I have my MBP with an audio interface connected to one TB port and the Caldigit hub connected to another.

Doing that introduced a tonne of weird interference and ticking on several synthesizer channels when working in Logic and Pro Tools. Unplug the USB from the synth and the noise goes away.

Plugging the interface back into the hub instead of the computer and the noise goes away.

It doesn’t appear to matter which thing is plugged into which thunderbolt port… if two thunderbolt ports are in use, I get noise across the USB peripherals.

Can anyone think of any logical reason why it would be absolutely perfect with a single cable setup into the Caldigit, but noisy in a multi cable setup?

 

[Bigwaff]

Did you try CalDigit on one side and USB interface on other side of MBP?

 

[Shadow Puppets]

Did you try CalDigit on one side and USB interface on other side of MBP?

Yep, the noise was there.

 

[BrianBaughn]

Could be the cables…or a grounding issue…or a combination of those. Only way to check the cables is to try different ones, I guess.

Are you in the USA and does the power supply have a three-prong plug? Is your home/office grounded properly? Does this happen both when the MBP is on battery power as well as when connected to a charger?

I once had some weird buzzing on some powered speakers that I eliminated by using three-prong to two-prong plug adapters.