What Is DC Offset?

By Richard Pryn •  Updated: 04/27/22 •  6 min read
What Is DC Offset

When it comes to sound editing and audio management, a lot of words and phrases get thrown around without much explanation.

This can be super confusing when you’re just starting out and want to learn more about sound editing – but that’s where we come in.

You may have heard about something called DC offset but what is it? And how does it affect your music and sound?

Here we are going to be looking at DC offset including what it is and how it affects you and your work.
So, if you want to understand more about DC offset, check out our information below! 

What Is DC Offset?

DC offset is another name given to amplitude displacement or when your sound signal is set off from zero.

When you play music or any kind of sound, you imagine it visually in its waveform. This means you see it as a sound wave that goes up and down. This is your AC – your alternating current which dictates the frequency of your sound output.

However, running through the middle of your AC wave is a straight, flat line. This is known as the direct current – the DC.

It is sometimes called the zero because it does not have anything that will make it alive and move, thus why the DC always remains flat and still. 

Usually, the AC wave lines up its center with the DC line so everything is perfectly balanced.
However, when the AC wave is not lined up with the DC line and is instead either shifted above (positively) or below (negatively) the DC line, then you create a DC offset.

This is when most of the AC wave is either above the DC line or below the DC line. It’s not equally set with half below and half above because the AC is not lined up with the DC.

It is ‘offset’ from the DC, or you could phrase it as that the amplitude is displaced. 

The main cause of DC offset usually has to do with the voltage offset in the audio chain. Faulty audio interface or soundcards can cause a lot of DC offset, as well as poor quality equipment or any defects in your hardware.

However, even if your equipment is all very high quality and there are no faults in the chain, then you can still have a low level of DC offset.

It’s difficult to avoid but luckily, easy to fix.

Is DC Offset Bad?

What Is DC Offset (1)

DC offset can negatively affect your audio because it causes clipping, distortion and a loss of volume, especially when working with amplifiers.

This is because your audio is working in a range either above or below the DC line and when it crosses over the DC line, the wave will clip because it is not balanced.

This clipping is also very noticeable when you try and paste two audios together, and you will often hear a click on the start or end of a track even if you haven’t started editing – that is due to DC offset. 

Clipping is not the only side effect of DC offset as it also severely impacts the volume level of your audio. It reduces the room between the peak level of your audio and the maximum possible volume, and this will make your audio sound quieter overall. 

DC offset is also responsible for distortion in your audio too, and this distortion becomes more noticeable as you edit with the audio and start extorting it into different formats.

Amplifying or normalizing your audio will make the DC offset a lot more noticeable and this can ruin the overall quality of your audio. 

Because of this, DC offset is usually the first thing tackled in the editing process before anything else as it always occurs during recording. 

How To Fix DC Offset With Your Audio

So, DC offset is bad and you need to get rid of it – but how?

Then get rid of any DC offset in your audio, then you need to correct the AC wave and bring it back in line with the DC line.

This will balance out your audio and return it to the range it is meant to be in, preventing it from clipping and distorting any further. 

So how do you do this? 

Luckily, a lot of computers with audio editing software already come with a quick and easy DC offset cancellation feature – you just have to find it and enable it. 

To start, right click the speaker icon over on the System Tray on your editing software and click select. Then, you need to enable each device in your Disabled and Disconnected Devices. 

Over each new enabled device, you need to right click again and choose Properties, then Enhancements. Some software will not have an Enhancements option but instead Hardware and Sound. 

Here, you should be able to find the ‘Fix DC Offset’ option. Click it and your computer will line up your AC wave with the DC line straight away for you and automatically fix any DC offset. 

This is a super handy feature that all sound editors and musicians use because it helps get rid of a common issue with minimal fuss or effort.

However, it’s important that you remember to do this fix right before you start editing any other features of your audio – this is because DC offset can seriously impact your audio and if you make any changes beforehand, it will sound completely different once you have gotten rid of the DC offset. 

Conclusion

So, DC offset is a huge issue that affects all forms of audio recording and is one of the first fixes every sound editor makes before anything else.

This is because DC offset is usually behind a lot of quality issues like clipping, distortion and volume restriction. Fixing this offset first allows you to set your audio to its original quality so you can make any other edits that you desire.

Because of this, a lot of audio editing software automatically comes with a ‘Fix DC Offset’ option for ease of use. 

So, now you know what DC offset is and how to fix it, you can now improve the quality of your audio for good! 

Richard Pryn

Hey there. I am an award winning composer for movie trailers, including Bladerunner 2049, Diablo II, WandaVision, and loads more. I am the founder of The Trailer Music School where my aim is to teach everything I know about music composition, production, and generally being a functional human being. I podcast, blog, vlog and jog (sometimes). I also love coffee, nachos and self-improvement. I live with my wife, three kids and numerous pets. I am also known by my pseudonym, Richard Schrieber (it’s a long story).

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