Hum and buzz on BL3s to Theatre

12 replies
Hi mPartio,

If you are getting a low frequency buzz or hum then this points to poor grounding. This is quite common where Cat cables have been used, particularly if some of the adapters or connectors are not suitably shielded. I suggest trying a direct cable connection from the Theatre to each speaker to give the best chance of a good connection, you can see suitable cables here:-

https://soundsheavenly.com/43-powerlink-rj45-cat5-connection-models-from-2013

Kind regards, Steve.

Location: The cable workshop, England

My B&O Icons:

Beoremote-Beo4.png Beoremote-Beo4.png
Beovox.png Beovox.png
Beotime.png Beotime.png
Beosound.png Beosound.png
Beosound-Moment.png Beosound-Moment.png
Beosound-Level.png Beosound-Level.png
Beosound-Emerge.png Beosound-Emerge.png
Beosound-A5.png Beosound-A5.png
Beosound-9000.png Beosound-9000.png
Beoplay-V1.png Beoplay-V1.png
Beoplay-H100.png Beoplay-H100.png
Beoplay-H95.png Beoplay-H95.png
Beoplay-H9i.png Beoplay-H9i.png
Beoplay-H4.png Beoplay-H4.png
Beoplay-H3.png Beoplay-H3.png
Beoplay-Form-2i.png Beoplay-Form-2i.png
Beoplay-E8.png Beoplay-E8.png
Beoplay-E4.png Beoplay-E4.png
Beoplay-Beolit17.png Beoplay-Beolit17.png
Beoplay-A1.png Beoplay-A1.png
Beomaster.png Beomaster.png
Beolab-18.png Beolab-18.png
Beogram-400x.png Beogram-400x.png
Cables, friendly advice and great ideas for connecting Bang & Olufsen! Ask any questions at https://soundsheavenly.com to get the best from your B&O! Please visit my B&O YouTube channel at https://www.youtube.com/soundsheavenlycables
Reviving an old thread… Is there any way to eliminate the buzz, assuming that Cat cables were used, and it’s not an option to run new cabling?

I’m getting a constant buzz in this scenario:

Beosystem 3 (in a media closet)  -> PL to Cat adaptor -> Cat cables (built into walls) -> Cat to PL adaptor -> BL 7-2

Replacing the cat cable is not an option, and I can’t run a new PL cable the whole length. Any options here?

Location: USA / Denmark

My B&O Icons:

Beovision-Avant.png Beovision-Avant.png
Beosound.png Beosound.png
Beosound-Theatre-.png Beosound-Theatre-.png
Beosound-Stage.png Beosound-Stage.png
Beosound-9000.png Beosound-9000.png
Beosound-2.png Beosound-2.png
Beoplay-M5.png Beoplay-M5.png
Beoplay-M3.png Beoplay-M3.png
Beoplay-H4.png Beoplay-H4.png
Beoplay-EX.png Beoplay-EX.png
Beoplay-A9.png Beoplay-A9.png
Beoplay-A8.png Beoplay-A8.png
Beoplay-A6.png Beoplay-A6.png
Beoplay-A1.png Beoplay-A1.png
Beolab-18.png Beolab-18.png
Beolab-8.png Beolab-8.png
or
BeoWorld Gold Membership card
Join BeoWorld

Register to access the forums, reference material, and exclusive member benefits — including our monthly prize draw.

Become a Member

December 2026 Prize Draw

Gold Members Only

As a Gold member you're automatically entered into our exclusive prize draw — your chance to win iconic Bang & Olufsen products. A unique benefit of BeoWorld Gold membership, every draw brings a new opportunity to win something special.