Mastering is the key link in the supply chain for your music. It bridges the gap between art and science, where the subjective meets the objective and where the rubber meets the road for releasing your music. Mastering is the final opportunity for fine-tuning your mix to meet the technical requirements for distribution and of course your final quality control check to make sure your song sounds absolutely BANGING!

Historically, mastering was simply a transfer process, creating a master copy for various formats, like vinyl, tape, or CD. Each format had its own limitations that needed to be considered when transferring the final mixes. To ensure the best possible replication and sound quality, technical and creative processes, such as compression and EQ, were applied.

Mastering has evolved over the years with the loudness wars, where artists competed (and still do) for the loudest sound. This turned Mastering into what it is today, with a seemingly never ending supply of new tools offering artists “the perfect sound” but somehow never quite living up to the sales pitch. This is because mastering is not an exact science; every song is unique. Some need minimal adjustments, while others require extensive fine-tuning. The real secret to a perfect master is in the decision making.

If you’re releasing music, even if only to stream online, you need to provide the distributor with a Master file that meets the technical requirements for the streaming and selling of your music. If we think about mastering from this perspective, it is the most essential stage of the process.

It’s not about using hardware, software, or any kind of processing specifically. It’s about ensuring your music shines in its brightest light even after it has been decoded for online streaming. Just because a platform level matches its audio, doesn’t mean all songs are now equal in quality. In fact the opposite can often be true. Mastering is the last chance you have to make sure your music sounds the absolute best it can.

Beyond the technical side, there's a creative aspect to mastering. The deeper a song can connect with the listener on an emotional level, the more likely it is the song will remain timeless, so enhancing that connection becomes a very important aspect of mastering.

Mastering has a significant impact on the sound of your music. It enhances the existing qualities of your mix, making it sound its best across all platforms. If your mix has issues, mastering can address some of them, but it's essential to understand that there's a balance to strike. You can only do so much at the mastering stage. For example, when increasing the presence of a dull song, the process may inadvertently accentuate any sibilance issues, leading to harshness. Mastering affects the song as a whole so processing individual sounds at the mastering stage, whilst not impossible and sometimes necessary, can have unintended consequences on the overall sound.

Mastering also typically involves adjusting the volume to match genre-specific standards. The goal is to retain the mix's vibe and feeling while making it competitively loud. The result should effortlessly evoke the artist's intended emotional response and create a spacious, immersive listening experience.

You should take my answer with a pinch of salt because I obviously want to be the one that’s mastering your music, but I’ll put forward some arguments for both and you can decide.

Mastering At Home.

Mastering your music at home is doable now more than ever. AI is being incorporated into many digital processors at an exponential rate. Tools like Izotope’s Ozone suite can help you get to a fairly decent sound with very little effort, knowledge or experience. You can even tell it how loud you want it to be and Alacazam! You’re done!

Even Logic’s latest update now has automatic mastering tools built into the software.

Mastering music at home gives you the freedom to release today’s studio session tonight. No waiting times and zero cost.

Hiring A Professional.

The obvious downside to song mastering at home is that you lose the external quality control check. Today’s studio session might be the best song in the world right now, but come the cold light of day the next morning, the quality is usually off by miles. What you thought was great, isn’t even good.

The biggest impact a professional can have on your song has nothing to do with what processing they apply during the song mastering, but rather, their ability to make objective decisions for the best of your song, in particular with context of how it will sound next to other songs in the same genre. Professional engineers have an extensive arsenal of tools and tricks that will help retain the original vision of the song even at much louder levels. This will usually be done within a genre specific sonic uniform, creating something unique that also matches perfectly with everything else around it. And then the very best audio mastering engineers, the true masters of the dark art and can create aural illusions of huge space and depth within heavily compressed audio. Making something that is technically over-compressed sound large, open and dynamic.

Listening :
More time spent listening to the song, identifying strengths and weaknesses, will mean less time guessing whilst mastering. A/B comparisons can help detect issues much faster and isolate imbalances in the audio that our brains quickly compensate for when listening in isolation.

Pre-Mastering:
Sometimes, a song needs minor adjustments for optimal mastering. Setting the right audio level is crucial to achieve the style of sound you want from the analog equipment. Phase corrections, if needed, can have a huge impact on the imaging of the sound. Many other reparative tools can be used to improve the quality of the pre-master before it is mastered.

Imaging:
This focuses on the perception of sounds within the stereo field. It's part of the mix as it correlates to the relationship between individual sounds but it is vital to be considered throughout the mastering process for heightening the listener's experience and emotional connection to the music.

Dynamic Control:
Achieving the right balance between compression and transient preservation is essential. Compressors can resolve many problems in the mastering chain but they can also create a lot of them too. When used correctly, it should anchor the necessary parts in place, solidify the imaging and enhance the song flow.

Tonal Enhancements:
This step brings out the best in the song, enhancing its space, depth, and presence. Highlighting and accentuating specific elements using tools like EQ, compressors, and distortion units. The goal is always to bring the best out of the song. Sometimes that means decreasing frequencies that are “bad” and sometimes it means increasing frequencies that are “good”. Other times introducing new harmonic frequencies is needed. EQ can be used to manipulate many aural illusions, adding space, depth, power and/or presence, especially post-compression. Magic can be pulled out of the proverbial hat during this part of the process.

Stereo Imaging / Depth Perception:
Everyone knows that widening an image can make it sound bigger, but few realise the power of depth. Consider both width and depth to create a 3D sonic image that enhances the listening experience by creating an intimate space within the song for the listener to fit inside.

Loudness:
Finding the perfect loudness level for the genre and instrumentation is crucial. Every song has a maximum optimal loudness which is determined during the mixing stage. When a song’s optimal loudness matches its genre’s general loudness, optimal quality can easily be achieved without the diminishing returns of compressors thinning out the sound for the sake of volume.

Final QC Checks and Rendering:
A final listening check of the recorded master (or the bounced master if you are working digital only) helps confirm processing decisions, ensuring a flawless master.

Client Feedback:
Artists play a pivotal role in the mastering process. They must have final say and approval of the mastering. Spending time with the master, listening on various speakers, and giving feedback is essential for leaning in to the magic and pulling the best out of the song. Mastering engineers have different rules for revisions so make sure you know what they are before committing to work with a new engineer for the first time to avoid unexpectedly large bills.

Preparing for Distribution:
After approval, the master is prepared for distribution, undergoing a dithering process to help maintain quality through codec compression for streaming. Metadata and ISRCs may also be embedded for efficient distribution and collection of royalties. Alternate versions may be needed such as radio edits or instrumentals, these can be run alongside the main mix during the mastering process.

Producing
- Music production encompasses songwriting, arrangement, and recording.

- Often intertwined with mixing, some music genres combine production and mix as one process.

- Historically, a producer wasn't necessarily a songwriter but had a knack for extracting a song's best elements, making the song accessible to a wider audience.

- A producer oversees the recording process, ensuring quality instrument recordings and top-notch samples.

- Producers ensure that instruments are well-recorded and all the source material is high quality, often leaving the nuances of sound balance and experimentation for the mix stage.

- Production completes when all parts are chosen, recorded, and arranged, even if effects come later during the mixing stage.

Mixing
- Mixing involves balancing and merging individual song elements into a single playable file.

- Mixing is needed because most individual sounds span the entire frequency spectrum, meaning high register sounds may still have low frequencies which are prone to clashes with more important sounds in that range.

- The mix engineer resolves clashes, ensuring each sound optimally plays its intended role.

- Mixing is a cumulative process, built layer by layer, requiring attention to details at every step to make the next step work.

- It's challenging to define when a mix is finished, but a playback from start to finish should ensure the lead element's uninterrupted flow with ease of listening.

- A finished mix should represent the song seamlessly, creating a harmonious, emotional listening experience without thought from the listener.

Mastering
- Mastering is the last step in transferring the finished mix into a distribution-ready format.

- This might involve creating a physical master for vinyl, tape, or CD or a digital master for online platforms.

- The mastered track should sound excellent across various platforms and speaker types.

- It enhances the best aspects of the song while maintaining a dynamic structure at competitive loudness levels.

- Reparative work can be performed, but generally speaking, the more repairs, the fewer the enhancements

- Sometimes, mix issues only become apparent during mastering, necessitating a strong partnership between mix and mastering engineers.

- Mastering serves as the final quality check before a song goes out into the world.

This is a fairly loaded question for me, of course I’m going to say analog is better because I use analog equipment for mastering over 90% of the time, but the reality is that whether something is good or not in the first place is partly a subjective choice.

Having said that, there is a reason why digital emulations of Class A components are a fraction of the price of their originals. If digital emulations truly sounded as good as their analog counterparts it would make no logical sense to keep making the analog units. There is a characteristic of analog processing that is still not obtainable by digital emulations. The result is instant added depth, even without settings applied, simply running an audio signal through the equipment with no settings alters the perception of the sound. Part of what is causing this is the harmonic distortion added by expensive components, heating up real voltage and transferring energy through a live electrical circuit. This is no comparison to a computer’s binary interpretation of that process. Digital harmonic distortion seems to have a lifeless element usually caused by the digital truncation of the signal that causes aliasing effects, which audibly blur the image. More often than not it is the added volume of these processors that initially sounds good, rather than the processes themselves. Analog harmonic distortion in contrast adds richness, warmth, depth and what can only be described as…soul!

Using class A analog equipment, the process of mastering a track is simplified. Harmonic distortion when used carefully can play a huge role in bringing out the depth and character from a song. It’s not impossible to replicate digitally, but requires more processing to imitate the same characteristics, often this type of processing can introduce aliasing artifacts, so a fine balance must be drawn.

There are exceptions to the rule and they can be found in some of the electronic genres where the overall song compression creates such an intensity that the depth characteristics you get with analog equipment might not be essential to get the desired sound. Whilst that is true, a song mastered through analog compared to the same song mastered digitally might just “feel” bigger, even at level matched volume. The analog enhancing more of the front/back imaging where the digital enhances more of the up/down (loud/quiet) imaging.

Analog is not the silver bullet for a magical sound, whilst it does do something extraordinary to music, there is still a point of diminishing returns. Every song still has its maximum potential for loudness, pushing past this level will risk breaking the sound up no matter if you are using analog or digital.

The following points are guidelines only. I could provide cases to argue against almost every point I put across here, however, generally speaking, these are good practices to consider when preparing your track for mastering. I have a video series coming soon that goes into all of these points in much greater detail. Watch this space…

Level
- Aim for peaks around -6dbfs and rms fluctuating around -18dbfs or 0dbvu.

- These levels are optimal for analog equipment but can be adjusted during mastering to suit the desired sound.

- Avoid clipping transients at 0dbfs, which can lead to audible distortion.

Crest factor
- Crest factor, the difference between peak and rms levels, impacts loudness and dynamics.

- For rock and pop, a crest factor of 12db provides room for intensity and dynamic range.

- In EDM, a lower crest factor (e.g., 6db) may be suitable for a more compressed and loud sound.

Transients
- Consider the transients in your mix; ensure that all transients are consistently controlled.

- Mastering compressors work more predictably when transients are consistent.

- This helps maintain the macro-dynamics of your song's flow during mastering.

Bit Depth / Sample Rate
- Higher bit depth and sample rates offer the foundation for a high-resolution master.

- Use the same sample rate for bouncing pre-masters as in your project.

- Higher bit depth (e.g., 24 bit) captures more low-level detail for a richer sound.

Dithering
- Dithering is primarily used when reducing file quality, such as going from 24 bit to 16 bit.

- It can also help reduce aliasing from digital processors.

- Explore the creative uses of dithering to enhance your mix further.

Limiters
- Limiters should be used sparingly; avoid relying on them for the final sound.

- Mix into a limiter to understand how your sounds respond when pushed to their limits.

- The limiter can provide a rough limited version for referencing during mastering.

References
- Use reference tracks throughout your mix for a balanced perspective.

- Our brains adapt to audio, so references help you maintain a fresh perspective.

- Comparing your mix to professionally mixed tracks ensures it sounds great on various systems.

• When sending pre-masters for mastering, choose either WAV or AIFF formats. Both formats provide identical sound quality, with the main difference being that AIFF files may contain metadata and are exclusive to Apple.

• Focus on the resolution, as it's crucial. To ensure a high-resolution master, render your pre-masters at the highest available bit depth.

• The length of a song is not the primary concern in mastering. What truly matters is the song's content and how it evolves.

• For example, a 7-minute house track can be mastered consistently, while a 3-minute song with contrasting quiet and intense sections may require different settings for each segment, which can be addressed during mastering and edited together.

Selecting the ideal mastering engineer or studio is a pivotal step in presenting your music at its best. Here are some considerations to help you make an informed choice

Experience
Look for engineers or studios with a proven track record and experience in your music genre. Experienced professionals often have a better understanding of the nuances and requirements of different genres.

Portfolio
Review their previous work. Listen to samples of songs they've mastered to get a sense of their sound quality and style. This will help you determine if their work aligns with your artistic vision.

Communication
Good communication is key. Ensure they are open to discussing your vision, and they should be willing to answer your questions and provide insight into their process.

Client Feedback
Don't hesitate to ask for references or check online reviews and testimonials. Hearing about other artists' experiences can provide valuable insights.

Samples and References
Professional mastering engineers often have an extensive portfolio of released work that you can readily access. Listen to their previous projects to gauge their style and capabilities. For less experienced engineers, consider requesting test masters as a way to assess their skills and compatibility with your music.

Facilities
If you're considering a studio, visit the space if possible. The studio environment and equipment can impact the mastering process.

Budget
Set a realistic budget for your project and find professionals or studios that align with it. While quality is essential, there are skilled engineers and studios for various budget ranges.

Turnaround Time
Consider your project's timeline. Ensure the engineer or studio can meet your deadlines without rushing the process.

Compatibility
Choose someone who resonates with your music style and has the technical knowledge to enhance your sound without altering its essence.

Mastering Philosophy
It's essential to understand the mastering engineer's philosophy. Some focus on transparency, while others may add their artistic touch. Find someone whose approach aligns with your vision.

Remember that finding the right fit may take some time, but making the effort to choose the best mastering engineer or studio for your music is a vital step in the journey of creating a polished and professionally sounding final product.

The time and cost of audio mastering can vary depending on several factors. These include the complexity of the project, the specific mastering engineer or studio you choose, and the industry standards. Here's a general breakdown:

Time
The time required for mastering depends on the project's complexity, the number of tracks, and the revisions needed. Typically, it can take anywhere from a few hours to a few days. A single track can take as little as half an hour. It's essential to communicate your timeline with your chosen mastering engineer or studio to ensure that your expectations align.

Cost
The cost of mastering can also vary significantly. Professional mastering engineers often charge by the hour to allow for the complexity or simplicity of the project. If a project has well balanced mixes the mastering should be fairly straight forward, which will be reflected in the price. Projects that require experimentation, varying styles of mastering on each mix to find the perfect blend or multiple mix variations running through the same settings, will also be reflected in the price. Factors affecting the price include the engineer's experience, the number of tracks, and the level of service provided. On average, you can expect to pay anywhere from $75 all the way to $500 per track for professional mastering, mostly dependent on the engineer’s experience. Amateur or inexperienced engineers may look more like $25 to $50 per track. Keep in mind that these are ballpark figures, and the actual cost may differ based on your specific requirements.

When considering mastering, it's essential to communicate your needs clearly and seek quotes from different mastering engineers or studios to find the best fit for your project. Remember that investing in quality mastering can significantly enhance the sonic quality of your music and is an essential step in preparing your tracks for release.

Mastering can fix issues in the mix but only to a certain degree. Mastering focuses on the whole picture, changes are made to the entire song not individual elements. As much as possible, the mix should sound ready before it is mastered. The mastering process yields best results when enhancing the mix as opposed to fixing it. But that’s not to say you can’t fix problems at the mastering stage, you are just limited with what is possible.

EQing issues out at mastering is a fine line but not impossible. As with most of these answers, it all depends on the mix. As an example, let’s take a rock song, the guitars are panned hard left and right and the vocal is upfront. There’s a harsh, dissonant harmonic ringing out in the guitars that masks the clarity of the vocal slightly. EQing this frequency out across the whole mix will take some aspect of the vocal out, too. But EQing the frequency out of just the side information, can resolve the clashing frequency and keep the vocal’s presence in tact. Times when EQ is not so great in mastering is fixing an issue between two instruments that share the same frequency range in the same part of the stereo field. Pultec style EQ can go some way to improving clashes like this but ultimately any EQ you apply to this range will affect both instruments together so may not resolve the issue.

The same is true with compression, to a certain degree compression issues can be resolved during mastering, but the processing is applied to the whole track, not to individual elements. Multiband compression can help fine tune things but the same is also true, anything within the frequency band you are processing will be affected.

A mastering engineer should be able to clearly distinguish issues that are or aren’t resolvable at the mastering stage and consult the artist with suggestions for mix amendments prior to mastering. Even when that happens, some mix issues aren’t revealed until the track is mastered so working with a mastering engineer that is a great communicator will help get to the magic faster.

Ironically, distortion can play a key role in achieving competitive loudness while maintaining sound quality during mastering. Unwanted distortion typically occurs when a limiter applies excessive gain reduction too quickly. Clipping happens when the limiter suddenly trims the peaks from a waveform.

Clipping transients can be beneficial, creating additional headroom in the mix with minimal audible difference. However, clipping of the sustain portions can introduce harsh harmonics and disrupt the overall timbre, which is perceived as undesirable distortion. In some cases, using saturators and distortion units can be more effective than traditional limiters. They add perceived loudness through harmonic distortion, enriching the sound's sustain while only clipping the transients.

Another technique involves using multiple limiters, each applying gentle limiting, which can yield better results compared to a single limiter doing all the work.

Analog mastering can take a different approach to this, using non-linear gain staging within the chain of equipment. This gradually increases the song's level as it passes through each unit, leveraging high headroom to find the song's natural limit before clipping the sound back to 0dB during the digital conversion stage using a very high-quality A/D converter.

Contrary to popular belief, the best mastering results often come from using the least amount of limiting.

Streaming platforms have significantly influenced the mastering process, primarily in two key areas:

Codec Compression
When preparing music for online streaming, songs are compressed into formats like MP3 or AAC. During this conversion, quantization errors may introduce unwanted artifacts, such as noise or distortion. Additionally, transferring digital audio back to analog systems for playback can result in interpolation errors, leading to inter-sample peaks above 0 dBFS, which may sound like distortion on certain playback devices. To address these issues, the "mastered for iTunes" (now known as "Apple Digital Masters") standard emerged, emphasizing lower levels to minimize inter-sample peaks. Dithering, even when not reducing the bit depth, is a useful tool in mitigating codec-related problems.

Level Normalization
In recent years, streaming platforms have been implementing loudness normalization standards, measured in ‘LUFs’ (Loudness Units Full Scale). This standardization aims to maintain consistent listening levels across all songs for a seamless listening experience. However, strict adherence to these standards can affect certain genres, particularly electronic music that relies on compression as part of its aesthetic. Mastering to meet streaming platforms' level targets can sometimes result in tracks that sound weaker and quieter than intended when streamed, impacting the song's full potential.

By addressing these aspects, mastering engineers navigate the evolving landscape of streaming platforms to ensure their music retains its intended quality and impact.

The role of a mastering engineer in vinyl mastering can vary based on the specifics of the record and the audio program. Typically, the engineer responsible for cutting the lacquer plays the only role in the vinyl mastering process but the mastering engineer can play a part in the preparation of the audio in some cases. The key considerations are the length of each side of the record and the audio's density. When audio is heavily compressed and, as a result, has higher Loudness Units Full Scale (LUFs), it becomes denser and occupies more space on the lacquer. This reduces the available cutting time for each side.

In cases where all tracks are over-compressed, the gain needs to be significantly reduced, and the groove's depth narrowed to fit all the audio on a side. This can result in a thinner sound on the final record. To address this issue and improve the listening experience, it's often beneficial to remaster the audio specifically for the vinyl format. This tailored approach can create a more immersive and enjoyable listening experience by optimizing space and adding depth to the final record.

The Loudness War refers to the practice of artists increasingly pushing the loudness of recorded music to compete for listeners attention. The process can often mean a sacrifice in dynamics and character in exchange for louder volumes which can, at first, seem more exciting to listen to.

The Loudness War has taken many forms over the years, from 7 inch record juke boxes, to radio broadcasting, the transfer from analog to digital formats all the way up to online streaming today. Even with the introduction of volume normalisation on streaming platforms, techniques can still be utilised to increase the perceptional volume at a normalised level.

It remains an area of great controversy with artists and engineers on both sides of the argument staunchly against the other. Whether you push the volume of your music or not should be decided stylistically based on the individual song. Some songs lean into the excessive compression needed for loud volumes which becomes an aesthetic of the sound. Mastering these types of songs at a more commonly accepted dynamic level can leave the song lacking in energy and excitement.

In terms of its effects on mastering, the Loudness War has had a significant impact. The pursuit of loudness often involves aggressive use of limiting, which can lead to audible distortion and reduced audio quality. It diminishes the nuances and dynamics of some music, making it less enjoyable for listeners who may find it fatiguing. As a result, mastering engineers are faced with the challenge of balancing loudness with audio quality and the preservation of musical dynamics.

• Receive Mastered Files in high-quality formats like WAV or AIFF.

• Add essential metadata (track titles, artist name, etc.) to your audio files.

• Create cover art that meets platform specifications.

• Encode lossy formats from your high-quality master using a reputable encoder.

• Embed ISRC codes in your audio files.

• Get a UPC or EAN code for tracking sales and distribution.

• Choose a digital music distributor like DistroKid or TuneCore.

• Ensure your files and artwork meet distributor format requirements.

• Fill out release information on the distributor's platform.

• Set distribution preferences and review your submission.

• Provide necessary banking and tax information for receiving royalties.

• Promote your music through various channels.

• Monitor your music's performance on platforms.

ISRC (International Standard Recording Code) codes whilst not mandatory, are essential for tracking and identifying audio recordings. They play a crucial role in the music industry for several reasons:

Identification
ISRC codes uniquely identify individual audio recordings, making it easier to track and catalog them. This is particularly useful when dealing with a large volume of audio content.

Royalty Payments
ISRC codes are used to ensure that the right artists, songwriters, and copyright holders receive their royalties when their music is played on various platforms, such as radio, streaming services, and TV.

Tracking Usage
Content creators, record labels, and musicians can monitor how often their songs are played and where. This data is valuable for assessing the popularity of a track and planning marketing strategies.

Preventing Piracy
ISRC codes can help in identifying and tracking unauthorized distribution and usage of copyrighted music, aiding in anti-piracy efforts.

To get ISRC codes, follow these steps:

Join a Recognized ISRC Manager You'll need to register with an organization that is authorized to issue ISRCs. In the United States, for instance, the Recording Industry Association of America (RIAA) and the International Federation of the Phonographic Industry (IFPI) are among the recognized ISRC managers.

Submit Your Information
Once registered, you'll provide details about your recordings, such as title, artist, release date, and audio format. You'll typically do this through an online platform provided by the ISRC manager.

Receive the Codes
After verifying your information, the ISRC manager will assign unique ISRC codes to each of your recordings. These codes are embedded into the metadata of the audio file.

Use the ISRC Codes
Make sure that the ISRC codes are included in the metadata of your audio files before distribution. They should be part of the recording's digital fingerprint.

By including ISRC codes in your recordings, you can effectively track and manage your music across various platforms and ensure that the right people receive their due royalties. It's an important step in protecting your music and your rights as a content creator.

Before and After examples of my mastering work can be found here.