Humming sound when using HDMI arc?

[Indydan]

I tried HDMI arc from my TV to my Wiim amp ultra. For some reason, it makes my subwoofer hum. The subwoofer hums even when the TV is switched off. Just plugging in the HDMI arc to the TV and Wiim amp ultra produces the hum. When I use optical instead, everything is fine.
I tried plugging everything in the same outlet. No change. I tried 3 different HDMI cables, no change. What could be causing this?

 

[HansD-NL]

You have (created) a ground loop. Maybe you have a cable box connected to the tv?
Using optical breaks the ground loop in your case.

 

[Indydan]

You have (created) a ground loop. Maybe you have a cable box connected to the tv?
Using optical breaks the ground loop in your case.

I have an Apple TV 4K and a 4K Blu Ray Player hooked up to the TV.

 

[HansD-NL]

It's not easy to diagnose a ground loop without hands-on access. Are your wall sockets grounded types, 3 pins with safety earth? Is the subwoofer a Class I (3 pin/earthed) or Class II (2 pin/no earth) device? The Apple TV is Class II, the tv is Class II (most are) and I guess the same for your Blue Ray player.
The WiiM Amp Ultra is Class I.

 

[Indydan]

Yes my wall sockets are grounded. The subwoofer is Class 1. Thank you.

 

[HansD-NL]

Ok, is the subwoofer (make & model?) located near where your other devices are, meaning on the same circuit of wall outlet(s)? Does the tv have other things not yet mentioned connected and does it have a antenna coax connected to it, if so where does the coax originate from (what device?)

 

[Indydan]

Ok, is the subwoofer (make & model?) located near where your other devices are, meaning on the same circuit of wall outlet(s)? Does the tv have other things not yet mentioned connected and does it have a antenna coax connected to it, if so where does the coax originate from (what device?)

The subwoofer (REL T5X) is connected to the same power strip as everything else. Only one outlet is being used. No coax or other devices.

 

[Aquaman]

Would reversing the polarity of the power plugs of any of the grounded devices help?
I would assume that one or more of the lives is making contact (ever so slightly and maybe just by inductivity) with the grounding.

In Europe not a problem, just turn the plug by 180 degrees. In other countries with directional plug/socket systems fitting an aftermarket plug or a soldering job will be required to test this

Just thinking out loud.

 

[HansD-NL]

Reversing a power plug can sometimes help with class II devices because there is en Y power filter inside which is not really 100% symmetrical. I'm sorry Indydan, with all the info you provided I can't see any obvious cause. Hands-on access (swapping things around) is needed for that. I hope that you will solve the problem and wish you all the best.

 

[harkpabst]

I have an Apple TV 4K and a 4K Blu Ray Player hooked up to the TV.

Are these the only sources? No kind of "antenna" or cable connection?

Did you try if disconnecting any of your sources makes a change to the humming? It's unfortunate, but there are lots and lots possible causes for hum.

 

[Indydan]

Thanks everyone for your help!
It is no big deal, I will just use the optical connection instead.

 

[Indydan]

Would changing the Rel for a Wiim sub pro using wifi solve the problem?

 

[Aquaman]

Would changing the Rel for a Wiim sub pro using wifi solve the problem?

If the humming stops when you physically disconnect your current sub from the Amp Ultra while the TV's HDMI is connected your plan will most probably work out. I've never heard of a hum being induced over wifi.

 

[Wiimer]

If the humming stops when you physically disconnect your current sub from the Amp Ultra while the TV's HDMI is connected your plan will most probably work out. I've never heard of a hum being induced over wifi.

Btw, could humming noise be caused by the subwoofer cable coming into contact with the power cable or adapter?

 

[Indydan]

If the humming stops when you physically disconnect your current sub from the Amp Ultra while the TV's HDMI is connected your plan will most probably work out. I've never heard of a hum being induced over wifi.

Thank you.

 

[Indydan]

Btw, could humming noise be caused by the subwoofer cable coming into contact with the power cable or adapter?

I don't think so. They are not close to each other.

 

[Indydan]

I tried something new to try and stop the hum when using HDMI arc.
I plugged an optical fiber HDMI cable from the TV to the Wiim amp ultra (instead of a copper HDMI cable). No change! The subwoofer still hums.
I will keep using the optical connection.

 

[MotleyG]

I plugged an optical fiber HDMI cable from the TV to the Wiim amp ultra (instead of a copper HDMI cable). N

The cable still has a ground shield connectin between the devices. Only the data is converted to optical, transmitted from source to display, then converted back in the cable to continue on it's way. Any noise will remain if the common ground between your two devices is not isolated. This needs to be eliminated at the real source of the problem.