Welcome to Acoustic Frontiers Blog

Creating a system you love shouldn't be difficult. The Acoustic Frontiers blog is here to help.

Hum and buzz in audio systems and home theaters

by Nyal Mellor April 08, 2013

What effect does 'hum' and 'buzz' have?

'Hum' and 'buzz' can cause major noise issues with our high performance audiovisual systems.
  • Hum is a superposition of the 60Hz mains AC frequency on the audio or video signal.
  • Buzz is a superposition of the harmonics of the 60Hz (120Hz, 180Hz, etc) mains AC frequency on the audio or video signal.

How is hum and buzz caused?

There are three main mechanisms that cause hum and buzz:
  • Interchassis currents between pieces of equipment with OR without a saftey ground as a result of 'stray' capacitance in the power supply
  • Ground loops - more specifically differences in the voltage of the safety ground wire between interconnected equipment
  • Electromagnetic coupling of AC and signal cables
For a more detailed discussion we suggest reading the Jensen Transformers guides below.


How do I solve hum and buzz?

A common root cause of hum issues are ground loops caused by equipment being on different electrical circuits or being plugged into different outlets on the same electrical circuit. The solution to this is to use good grounding practices - i.e. having a single grounding point for equipment and connecting all equipment to this with short, high gauge (low impedance) power leads. Powerbridges (in wall electrical circuits that are not always connected to the home electrical system; they are essentially normally de-energized electrical circuits that are energized when one end is plugged into the outlet of a power conditioner or UPS) can be used for subwoofer and projector in wall runs. In most other cases the root cause of hum and buzz can be tracked down to a single interface between two pieces of equipment. We suggest using the Isomax Troubleshooting Guide to identify the root cause of the hum and buzz issue. The solution is generally to isolate the two components as follows: Whatever you do, do not float the ground using a cheater plug! The ground is there to protect you from electrocution.


References and further reading:

Understandingfinding and eliminating AV ground loops, Bill Whitlock, Jensen Transformers. Balanced lines in audio systems: fact, fiction and transformers, Bill Whitlock, Journal of the Audio Engineering Society, Vol 43, June 1995 Hum and buzz in unbalanced interconnect systems, Bill Whitlock, Jensen Transformers application note AN-004. Isomax troubleshooting guide, Bill Whitlock, Jensen Transformers

GET THE RESULTS YOU'RE LOOKING FOR WITH ACOUSTIC FRONTIERS

  • You'll have a system you love.
  • You'll experience audio-video like never before.
  • You'll have no doubt you got the best performing system for your budget.

REQUEST A QUOTE




Nyal Mellor
Nyal Mellor

Author



Also in Blog Articles

Elevating Home Theater Design: The Crucial Role of Partnering with a Designer from the Start
Elevating Home Theater Design: The Crucial Role of Partnering with a Designer from the Start

by Nyal Mellor May 29, 2024 0 Comments

Learn why consulting with a professional when integrating a dedicated media space into architectural plans is crucial to avoiding costly mistakes and ensuring a truly immersive and unparalleled home entertainment experience.

Continue Reading

The Art of Sound: Creating the Ultimate Listening Room in a New Construction Project
The Art of Sound: Creating the Ultimate Listening Room in a New Construction Project

by Nyal Mellor April 28, 2024 0 Comments

"The room was easily the most important upgrade to my stereo system. I think it sounds fantastic and considerably better than anything I've heard at a dealer or audio shows.” - Len W.

Continue Reading

Investing in Excellence: The Value of Working with Professionals for Your Home Theater
Investing in Excellence: The Value of Working with Professionals for Your Home Theater

by Nyal Mellor March 30, 2024 0 Comments

Clint, an avid DIYer, planned on building his own home theater to cut costs until he realized the complexity of the task. "One piece of advice I came across most often was to hire a professional. I was hesitant, but I just found myself going in circles and didn't want to invest in something I'd later regret."

Continue Reading

Contact Us About This Product

video-design

Nyal Mellor, Founder, Acoustic Frontiers

  • (415) 524-8741
  • Serving USA & Canada
  • Fairfax, Northern California, USA

ask us a question about this product