Mastering for Width: Stereo Techniques and Tools

Learn the ins and outs of mastering for width, and the best plugins for the job

Mastering is the final stage in the journey of making a track in any genre. It provides extra polish and adds the finishing touches to ensure your music is ready for playback across a range of platforms – whether that’s a streaming service, the radio, vinyl, or a DJ set.

When you think of mastering, you may think of loudness. That’s certainly an important part of the process. Mastering engineers ensure that the track will sound loud when played, and will feel at home on the radio, or in a Spotify or Apple Music playlist. But loudness is only part of the equation – a well-mastered track will also be balanced in terms of both tone and stereo width.

The majority of stereo width adjustments will be made at the mixing stage. Here, you can pan individual elements, and give them a defined place in the stereo field. But you can still make tweaks when mastering. Though it’s impossible to reposition an individual element in the stereo field, you can adjust the balance between mid and side elements, and alter the overall stereo width of your master.

So, read on to discover some techniques you can use when adjusting the stereo field of your master, and some of the best tools for the job.

 

Consider the overall stereo image

The overall stereo image of your track is how “wide” it feels.

If your track's stereo image is too narrow, it can sound a little lifeless and uninteresting. However, if it is too wide, it can lose power and sound thin and weak.

One good way to determine an appropriate stereo width for your music is to compare it to professionally mastered releases by artists working in the same genre as you. Yes, you want your music to stand out – but you don’t want it to stick out like a sore thumb in a Spotify playlist because your master is far too narrow.

Different genres of music tend to be listened to in different contexts. For example, dance music is more likely to be played on a club sound system than a country tune. Club sound systems are often mono, and so dance music is less likely to contain as much stereo information as country. By comparing your song to other tracks in the same genre, you can help ensure that your music is suitably mastered to be played in its natural environment.

MCompare by MeldaProduction is the perfect tool for this job. It allows you to quickly compare your master buss with any audio file, so you can swap in several different tracks and compare your stereo image with that of the pros.

When considering the overall stereo image of your master, it’s also important to respect the mix. Yes, you can make adjustments to the stereo image when mastering – and sometimes this can add excitement and interest – however, you run the risk of upsetting the balance that the mixing engineer has achieved, even if you were the mixing engineer! For example, boosting the stereo image of your master could detract from the impact of important mono elements in the mixdown, while reducing the stereo image could mean panned vocal harmonies get lost.

 

Track elements in the stereo field

As touched on in the previous section, instruments and track elements typically occupy different parts of the stereo field in a mixdown.

Key elements such as kick and snare drums, basslines, and lead instrument lines like a vocal will typically be central in the stereo field, while complementary elements such as hi-hats, vocal harmonies and effects will be panned.

So, when increasing the width of a master, you may have to consider the balance between these track elements. Boosting width can bring out these panned, complementary elements if that's what you feel your track requires.

Using a mid-side EQ, such as Softube’s Chandler Limited® Curve Bender Mastering EQ can allow you to EQ just the side elements, enabling you to alter the stereo field of your master more surgically. For example, you can boost just the highs of your panned elements, without clashing with mid-range frequency information that may be happening in the centre of your stereo field.

 

Stereo image per section

Stereo image is a tool that can be used to create progressions and structure within a track.
This is the kind of thing that is likely to be added at the production or mixing phase. However, it can be tweaked and polished when mastering.

For example, widening the stereo image when transitioning from a verse to a chorus can help create impact and size. Alternatively, you could gradually reduce the stereo image of your track during your outro to signify the track's end.

 

When should you adjust the stereo image in the mastering chain?

There are no strict rules about where to adjust stereo image in your mastering signal chain, but there are some general best practices you can follow.

In audio work, it’s typically recommended to handle corrective processes early in the chain. Addressing issues upfront ensures you don’t risk amplifying problems later on through compression, saturation, or other processing.

For example, when de-noising, you would typically remove unwanted noise before compressing or saturating a signal. Likewise, if you, for example, need to reduce the stereo image of the bass in your track to avoid potential phase issues, do this early in your chain.

Conversely, creative processes normally come towards the end of the chain. So, if you want to create a bit more energy in your track by boosting the sides, it’s generally best to either do this as the last step in your chain (other than your limiter), or very close to the end.

 

Check your master in mono to spot phase issues

 

 

You may have heard this advice before in a mixing context, but it’s just as important when mastering: always check your master in mono after adjusting the stereo image.

In an ideal world, every listener would experience your track on a well-tuned stereo system or a high-quality pair of headphones. However, the reality is that many people will hear your music through budget devices, mono speakers, or other less-than-ideal setups.

By testing your master in mono, you can catch any phase issues caused by stereo widening or other processing, ensuring your track maintains its impact and clarity across all listening environments.

Phase issues occur when two or more versions of the same sound are slightly out of time with each other. When listening in stereo, this can create width and size, however, when summed to mono, these discrepancies can cancel each other out, leading to a loss of power in important elements like vocals, drums, or bass.

If you spot any phase problems, you may need to go back and adjust your stereo processing.

 

Mastering for width: a checklist

• Assess the stereo image of your master – compare it to professionally mastered tracks in your genre.
• Respect the original mix – don’t adjust the balance between the mid and sides too drastically.
• Consider how you could use stereo image to differentiate sections of your track.
• Correct stereo issues early in your mastering chain, and make creative adjustments at the end.
• Check your master in mono.
• Listen to your master on a range of sound systems.

 

Best stereo mastering plugins

 

Ozone 11 Advanced

The best all-around stereo mastering suite

Platforms:	Windows and Mac
Type:	Mastering Suite
Format:	AAX, Audio Units and VST3
Features:	Fully fledged mastering suite with plenty of stereo shaping features.

 

Chandler Limited® Curve Bender Mastering EQ

An emulation of an all-time great analogue mastering EQ

Platforms:	Windows and Mac
Type:	Mid/Side Mastering EQ
Format:	AAX, Audio Units, VST and VST3
Features:	A classic analogue mastering EQ gets the digital treatment, with an extra stereo twist thanks to mid/side processing.

 

MCompare

A fantastic analysis plugin for assessing the width of your master

Platforms:	Windows and Mac
Type:	Referencing Tool
Format:	AAX, Audio Units and VST3
Features:	A powerful tool for comparing the stereo width of your master to the work of the pros.

 

Center

Dedicated tool for adjusting stereo width

Platforms:	Windows and Mac
Type:	Mid/side processor
Format:	AAX, Audio Units and VST
Features:	Dedicated stereo width adjustment with a simple interface. This tool will help you balance your mids and sides quickly and easily when mastering.