Buzz, Hum and How to Get Rid of it

Singers forgetting the next lyric, drummers who struggle to stay in time, guitarists who keep playing that same bum note and buzzing audio gear … For all musicians, sound technicians and producers, these problems might be all too familiar. While we’re unfortunately unable to help with the first three, we can certainly offer up a little help with removing that annoying hum or buzz from your speakers or headphones by laying out four possible causes and audio-signal-cleansing solutions.

Corrupt Power Supply
Cabling
Ground Loops
It’s Just Broken
Also see …

Corrupt Power Supply

In most cases, annoying hum is caused by what we’ll call a ‘corrupt’ power supply since some devices literally ‘corrupt’ the electricity supply coming from a plug socket. Such devices are usually pretty power-hungry and include washing machines or electric hobs as well as obnoxious ‘buzz’-heavy devices like dimmers and old tube televisions. All of them can cause a peak in the power network that is then heard directly via any audio equipment. The obvious solution here is to turn off each device that can be found in the building, one by one while checking if the hum has been cleared up. As soon as it stops, you know that the culprit is the last device you turned off.

Cabling

A humming sound can also sneak into any audio cables so, whenever possible, it’s always best to use a balanced connection. To find out more about balanced connection and their many benefits, we have a handy little blog ready to explain all.

Buzz, Hum and How to Get Rid of it

Ground Loop

‘Ground loops’ happen when you connect two or more audio devices that are powered by a different voltage. For example, two power sockets could have different phases meaning that the voltage isn’t exactly the same and it’s this difference that can be heard back in the form of a buzzing or humming sound. Where possible and for any audio-setup, it’s therefore best to use one power socket. Of course, with larger setups, using more than one power point is unavoidable, so adding a DI box or ‘ground loop isolator’ will solve any possible problems. DI boxes take an unbalanced signal and put it through a balanced input and since most DI boxes will have a ‘ground lift’ function, enabling this will remove any noise caused by ground lift. Ground loop isolators have specially designed transformers that turn the electric signal into a magnetic field and then back again. Since this process breaks the ‘physical’ loop for the briefest of moments, the ground loop noise is removed.

It’s Just Broken

So, you’ve tried everything you can think of (including the above) but it still sounds like a mosquito is trapped in your speakers. It’s time to admit that part of the audio chain might be defective and in most cases, it’s going to be the power supply. The fitted inverter that does the job of converting alternating current from a power socket into direct current can deteriorate over time, so it might be worth replacing your power supply. If your power supply is brand new and you’re still plagued by buzz and hum, we’re sorry to say that your amplifier might be blown.

Did we forget something? Let us know in the comments section below!

Also See…

» DI Boxes
» Ground Loop Isolators
» Audio Cables

» Balanced and Unbalanced Connections (Finally) Explained
» How To Connect Your Speakers To Your Audio Equipment
» The Difference Between Active and Passive Speakers