How do you use mid-side processing to enhance or correct the master?

1 What is mid-side processing?

Mid-side processing is based on a simple mathematical formula that converts the left and right channels of a stereo signal into the mid and side channels. The mid channel is the sum of the left and right channels, while the side channel is the difference between them. The mid channel contains the audio information that is common to both speakers, such as the vocals, bass, kick, and snare. The side channel contains the audio information that is unique to each speaker, such as the panning, reverb, and ambience. By using a mid-side encoder and decoder, you can split and recombine the stereo signal and apply different processing to each channel.

2 Why use mid-side processing?

Mid-side processing can help you enhance or correct the master in various ways, depending on your intention and the source material. For instance, you could increase or decrease the stereo width by boosting or cutting the side channel. Additionally, you can add more depth and dimension by applying reverb or delay to the side channel. Furthermore, you can enhance clarity and focus by applying EQ or compression to the mid channel. Moreover, you can correct phase or balance issues by adjusting levels or polarity of the mid or side channel. Finally, you can create more contrast and interest by applying different effects or saturation to the mid or side channel.

3 How to use mid-side processing?

To use mid-side processing, you need a plugin or device to encode and decode the stereo signal into mid and side channels. Some plugins, such as Ozone or FabFilter Pro-Q, have a built-in mid-side mode that allows you to switch between the channels and apply different processing. Other plugins, such as Voxengo MSED or Brainworx bx_solo, can act as an encoder or decoder before or after the processing plugin. You can also use hardware devices, such as a matrix mixer or mid-side microphone. The basic steps for using mid-side processing include inserting an encoder before the processing plugin, choosing the channel to process (mid or side), applying the desired effect or adjustment, inserting a decoder after the processing plugin, checking the output level and adjusting it if needed, and using a correlation meter or phase scope to monitor the phase coherence and stereo image of the master.

4 What are some tips for using mid-side processing?

Mid-side processing can be a powerful and creative tool for mastering, however, it can also introduce some problems or artifacts if used incorrectly or excessively. To use mid-side processing effectively and safely, it's best to use it sparingly and subtly, as it can alter the original balance and intention of the mix. Additionally, make sure to use it selectively and specifically on the frequency range that needs it and with a narrow or steep filter, as it can affect the entire frequency spectrum. Moreover, use mid-side processing carefully and cautiously, as it can create phase or mono compatibility issues. Lastly, use it creatively and tastefully on the elements that are already interesting and with a suitable effect or saturation.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?