Sound Mixing It plays a critical role in achieving a balanced and cohesive audio track that enhances the emotional impact of the music. It requires technical knowledge, creativity, and skill to produce a great song or score

Sound mixing or audio mixing is a crucial process in music production that involves combining and adjusting individual audio tracks or elements of a song to create a final stereo or multichannel audio mix. Typically, audio engineers or producers perform this step.

The primary objective of the audio mixing process is to achieve a balanced, cohesive, and sonically pleasing sound that translates well across various playback systems, such as speakers and headphones. To accomplish this, sound mixers employ multiple tools and techniques to shape five key elements of the mix: balance, stereo image, tonal balance, dynamics, and space.

The balance element refers to adjusting the relative levels of separate tracks in the mix, while the stereo image involves creating a sense of width and depth within the stereo field.

Tonal balance is about ensuring that the frequencies of multiple sounds complement each other, while dynamics relate to manipulating the volume and intensity of the mix (quietest and loudest parts). Lastly, space creates a sense of depth and dimensionality in the mix.

Creative mixing is what elevates a good song into a great song.

A Brief History Of Recording and Mixing

Multitrack Recording

Recording with multiple tracks dates back to 1943 when stereo tape recording was invented, which partitioned the recording head from one track into tracks. A few years later, in 1948, physicist Marvin Camras developed a three-channel machine with three parallel magnetic tracks on the same tape. 

The next big breakthrough occurred in the mid-1950s when the Ampex corporation introduced the concept of 8-track recording using the "Sel-Sync" (Selective Synchronous) recording system, selling the first such machine to musician Les Paul.

Since then, multitrack recording and mixing have progressed significantly with new technologies and trends, keeping pace with the modern standards and expectations of the music industry. 

With the advent of faster and more powerful computers, recording and mixing have become more accessible and easier, enabling new producers to create great-sounding projects without spending long hours or training themselves on complex techniques. 

Established professionals also have access to even better tools and capabilities, expanding the limits of creativity and innovation. Recording and mixing music techniques are constantly evolving to meet the artists' and listeners' needs and preferences while adhering to the central principles of balance, clarity, and cohesion.

Multitrack Mixing

Mixing is a fundamental process that involves blending and adjusting all the sounds or elements of a song to create a final stereo or multichannel audio mix. It is a critical stage typically performed by a mixing engineer or producer.

Audio mixing has existed since the advent of recorded music, but it was primarily done manually until the late 1970s and early 1980s when technology began to influence audio production heavily. The introduction of multitrack tape machines, especially with the 8-track recorders during the 1960s, enabled the capture of sounds in different channels and processing them separately during a later mixing phase.

The introduction of digital recordings and computerized processing power in the late 1970s and early 1980s revolutionized the mixing process, providing producers and mixers with more control and flexibility over their project's sound and enabling new tools and techniques such as Auto-Tune, virtual instruments, and sound design.

It has evolved with new technologies and trends to keep up with modern standards and expectations in the music industry. As computers become faster and more powerful, mixing becomes more accessible and easier, allowing new producers to create great-sounding projects without spending long hours training themselves on complex techniques. It also gives established professionals access to even better tools and capabilities, expanding the limits of creativity and innovation. 

Digital Audio Workstations (DAWs)

A DAW, a digital audio workstation, is an electronic system or software application designed to facilitate audio file recording, editing, and production.

A DAW works by converting analog audio signals originating from microphones or instruments into digital data for manipulation on a computer. It uses an analog-to-digital converter (ADC) that samples the analog signal and produces a digital representation. This digital data is then processed and edited using various tools and effects available on the DAW.

A typical DAW features a graphical user interface (GUI) that displays audio tracks, mixers, effects, and other tools. Each audio track can be edited or manipulated. The user can manipulate and control virtual instruments such as synthesizers and samplers using MIDI commands transmitted from a MIDI keyboard or other MIDI-enabled devices.

A DAW can have different features and functions depending on the software or system used. Some standard functions of a DAW are:

• Recording and editing audio: A DAW can record and edit multiple audio tracks using tools like cut, copy, paste, trim, fade, crossfade, and apply effects like EQ, compression, reverb, and delay to enhance sound quality and character.

• Mixing and mastering audio: A DAW can adjust the audio levels, panning, and balance of audio tracks, group and process them using subgroups and buses, and apply plug ins like limiting, dithering, and stereo enhancement to optimize the loudness, quality, and compatibility of the audio mix.

• Playing and composing with virtual instruments: A DAW enables playing and composing with virtual instruments that emulate natural or synthetic sounds, like piano, guitar, drums, strings, and more. It also uses MIDI keyboards, controllers, and sequencers to input and edit MIDI data to trigger virtual instruments.

Types Of Sound Mixing

Top-down mixing and bottom-up mixing are two different strategies for mixing audio. They differ in the order of processing the audio tracks, from the mix bus to the individual tracks or vice versa.

Top-Down Mixing

Top-down mixing is a mixing technique that involves processing the mix bus first, followed by the subgroups and individual tracks. This method prioritizes the overall sound and creates a uniform mix by working from the top-level details to the finer ones. It is valuable for achieving a cohesive, well-balanced mix, especially in complex productions.

To apply top-down mixing, follow these steps:

1. To organize the tracks, create four subgroups and route them to the master bus. Make sure your master fader is at unity gain.

2. Add a bus compressor, EQ, and limiter to the master bus and adjust their settings to achieve the desired overall sound and loudness of the mix.

3. Apply EQ, compression, and reverb to each subgroup, like the drum bus, adjusting the settings to improve the sound and balance of each track while considering the impact on the master bus processing.

4. Balance the tracks by adjusting the subgroups and volume faders. Utilize effects like panning and automation for added movement and interest in the mix.

5. Make final adjustments to the mix as a whole. Avoid over-tweaking individual tracks, but feel free to make necessary adjustments if required.

In top-down mixing, start with the big picture and work on the details. A typical example would be using a master buss chain on an EDM Mixing session to ensure standard loudness levels without clipping or distortion.

Bottom-Up Mixing

The bottom-up mixing strategy is where mixers begin the mixing process by processing individual tracks, progressing to subgroup processing, and finally, mix bus processing. This method emphasizes paying attention to details, carefully layering, and combining the elements of each track to build up the mix.

To apply bottom-up mixing, follow these steps:

1. Apply processing to each track, like EQ, compressor, reverb, and delay. Adjust the settings to improve the sound and clarity while removing unwanted frequencies and noises.

2. Adjust the volume faders and un-solo the tracks for a balanced mix. Utilize panning, automation, and effects to add interest and movement.

3. Create four subgroups for each track and add processing such as a bus compressor, EQ, and saturation. Route them to the master bus and adjust settings to create a cohesive mix.

4. Add some processing to the master bus, such as a limiter, a stereo enhancer, and a dither. Adjust the settings to achieve the desired loudness, width, and mix quality.

5. Make final adjustments to the mix as a whole. Don't overdo it. You can also tweak individual tracks or subgroups if needed.

This is a simple bottom-up mixing process, but you can adjust it to your liking and style. The key concept is to begin with small details and gradually move towards the bigger picture. A disadvantage of using this technique is when mix engineers lose perspective of the entire mix by focusing on each individual track.

This technique is also commonly used in the video editing post-production process, as the top-down mixing style limits the dynamic range to a certain extent. It's better to have full dynamics and headroom during the mixing stage so the louder parts don't get severely limited.

Mixing Techniques

Mixing techniques are the methods and tools used to blend and process individual audio tracks or elements of a song to create a final stereo or multichannel audio mix.

The key to a good mix is a good grasp of the fundamentals. It's important to hear the difference between elements on the same level and balancing other elements around it. Listen for noise and add effects only when necessary.

Mixing techniques can vary depending on the genre, style, and preference of the producer or engineer, but some common ones are:

Gain Staging

Gain staging is a crucial process ensuring that audio signals are transmitted through equipment or software at optimal levels without distortion, noise, or clipping. This process involves setting the input and output levels of each stage of the signal chain to achieve a clean and balanced signal. 

The signal chain includes components such as preamps, microphones, effects, and faders, each of which must be carefully adjusted to avoid unwanted noise or distortion. 

Effective gain staging improves the overall sound quality and prevents any potential damage to the equipment due to overloading or clipping. 

Pay close attention to each track for any signs of clipping or any errors done during recording so that it can easily be rectified at this stage before any editing is done.

Level Balancing

This process involves adjusting the volume of each track or element in the mix to achieve a balanced and cohesive sound. A rough mix is done when all the tracks are balanced but processed with little to no effects added. This preserves the dynamic range of each track and gives an overview of the entire song.

The art of level balancing helps to create a sense of depth, space, and dynamics in the mix and is one of the critical factors in producing a high-quality audio track. 

By adjusting the levels of different elements, such as drums, bass, guitar, and vocals, the mixer can bring out the best in each element, ensuring they all work together harmoniously. The mixing console can also emphasize the most important aspects of the song by adjusting their levels to make them stand out in the mix. 

Level balancing is about setting the volume of each element in the mix and creating a sense of space and depth. By adjusting the levels of different elements, the mixer can develop a sense of distance between them, making the mix sound more three-dimensional. 

In addition, level balancing is essential to creating dynamics in the mix. By adjusting the levels of different elements, the mixer can create volume changes that help keep the listener engaged and interested in the music.

Panning

Panning is an essential process in audio production that involves the distribution of sound across the stereo or surround field by manipulating the levels of the left and right channels. By doing so, panning music elements allows the sound engineer to position each track or element in the mix, creating a sense of width, separation, and movement.

This technique is beneficial in achieving a balanced and cohesive mix, as it helps to avoid frequency masking and phase issues that can arise from overlapping sounds or conflicting frequencies. By putting each element in a proper place in the audio space, a more immersive sound can be achieved.

Stereo Vs Surround Sound

Stereo Sound

Stereophonic sound, commonly called stereo, is an audio reproduction method that utilizes two or more loudspeakers placed in different positions to replicate sound. The primary objective of stereo sound is to create a more authentic and immersive listening experience similar to natural hearing. 

The term "stereophonic" is derived from the Greek words stereos, meaning "solid," and phōnē, meaning "sound." The term's origin can be traced back to Western Electric, the company that first coined it. 

In technical terms, stereo refers to sound recording and playback using two channels of audio data typically positioned at different angles and distances from the listener, making them hear a three-dimensional sound field. Using automation to move sounds across the stereo field can make a static mix into a dynamic mix.

Stereo sound has become a standard feature in most modern audio and entertainment systems, providing users with a more realistic and engaging audio experience.

Surround Sound

If you've been in a movie theater and watched a scene where the main character is being circled by another, you would hear the second person's voice go around your field of hearing because of surround sound.

Surround sound is a technology that adds multiple channels to sound reproduction, offering an immersive experience to the listener. It consists of speakers placed around the listener, and each group has its own channel. The setup can range from 2 or 3 speakers in the front and 2 in the back up to 24 speakers. 

Channels are treated differently in surround sound to create unique sound effects. However, this technology is relatively new, and the music industry is still working to establish standards for listening to surround sound. 

The most common surround sound systems use five basic channels and one special channel to reproduce the recording. Cinemas and theatres need six speakers to play surround sound. 

The sound field in surround sound includes left, right, and center sounds and additional positions like Surround-L and Surround-R, with speakers placed behind the listener. The sixth channel, LFE (Low-Frequency Effects), includes low frequencies typically used for special sound effects.

Prepping For Mixing

Effective music mixing involves selecting the desired audio elements and editing out any unwanted components that may detract from the final mix. This process may include excluding specific instruments or certain parts of an instrument's performance.

Additionally, it is common practice to eliminate any extraneous noise that may have been captured during the recording process. By carefully managing both the inclusion and exclusion of audio components, a skilled sound mixer can produce a cohesive and polished final product.

Noise Gating and Noise Reduction

Noise is a common problem in audio mixing, arising from various sources such as headphone leakage on the vocal track, electric guitar humming, and unwanted background sounds. Manually editing out noise can be a chore but it can spell the difference between a good mix and a bad mix. Noise also gets brought up when you normalize audio.

Removing or retaining certain noises during mixing is not explicitly governed by any hard and fast rules and depends on factors such as the genre of music, the band's preferences, and the available mixing tools.

Sometimes, noise is deliberately added to create a unique auditory experience for the listener. Whether mixing a single track or multiple tracks, it is important to consider the impact of noise on the final output.

Arrangement

While a live orchestra's instruments naturally know when to start and rest playing following sheet music, a mixing engineer needs to simulate this behavior with individual tracks. To properly accomplish this, in live settings, you'll need a sound team. This is why churches and musical venues often have a dedicated sound department.

Arrangement can also make its way into the mixing process. For example, the mix engineer can add or remove instruments, vocals, and other sounds in different parts of the track.

To achieve a more exciting and dynamic recording, it is recommended to begin with lower loudness and less complexity during the first verse, gradually adding or unmuting elements as the song progresses. This helps create a thrilling build-up that captures your listeners' attention.

Some tips to keep your session organized

Color Code Track Groups

Assigning distinctive colors to your track groups based on their role and function can significantly enhance the organization and visibility of your mixing project.

By consistently categorizing, for instance, all guitar tracks in blue and all vocal tracks in red, you can instantly distinguish between different elements in your mix, allowing you to apply specific processing and adjustments with greater ease.

This approach can vastly improve your workflow efficiency and help you achieve a more balanced and polished mix.

Name Your Tracks

Properly labeling each track in your mix is crucial, even if you only deal with a few tracks. You can easily navigate your mix by assigning appropriate names to each track based on their functionality, especially when working with more extensive sessions.

Putting this into practice can help you save time and effort and ensure a smooth and efficient mixing process.

Final Thoughts

Sound mixing plays a critical role in achieving a balanced and cohesive audio track that enhances the emotional impact of the music. Producing a great song or score requires technical knowledge, creativity, and skill.

What does a music producer do? With digital audio workstations and advanced mixing tools, sound mixing has become more accessible and efficient. By utilizing various techniques such as EQ, compression, and automation, experienced mixing engineers can achieve precise control over the tonal and dynamic aspects of the audio signal, resulting in a polished and professional sound, where the music sounds good.

However, mastering the principles of sound mixing is a continuous learning process that involves staying up-to-date with the latest technologies and techniques to produce the highest quality audio possible.

Contributors:

• Alexander Briones - Editor
• Jerry Borillo - Illustrator