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How to Master a Song
Audio Mastering is the final stage of the audio production process where you polish your mix and prepare it for distribution. While in mixing you’re editing the individual elements of a mix, when mastering music, you’re making subtle corrections and enhancements to the entire song.
In this article we’ll walk you through how to master a song and how you can use the latest in audio mastering software to optimize your workflow using Ozone and Tonal Balance Control.
Feel free to download a free trial of iZotope Ozone to follow along.
How to Master a Song
Mastering a song involves using tools like EQ, compression, limiting, and imagers to ensure the mix sounds loud and clear on different types of speakers and listening environments. The goal of mastering is to produce music that competes with other professionally mastered songs on the market so that it doesn’t sound out of place when heard on the radio, TV, streaming platforms, or other mediums. While there are many approaches to mastering music, we’ll focus on some of the most common steps to getting a great sound and how you can use Ozone to improve your audio mastering workflow. The main steps in mastering are:
- Finish your mix
- Bounce down your stereo track
- Start a new session and Import your stereo mix and reference tracks
- Listen to the mix and take notes
- Make level corrections with Master Rebalance if necessary
- Add clarity to the low end
- Correct the tone with EQ
- Tame your dynamics and glue your mix together
- Make EQ moves to match your reference
- Fix or enhance the stereo image
- Limit the mix
- Final mastering checks
- Bounce your master
1. Finish your mix
The first thing you want to do is finish the mix and prepare it for audio mastering. The mix should sound balanced, dynamically consistent, and have enough headroom for the mastering stage. Mastering music is a subtle art. Minor changes can make or break an entire mix so try to have a mix that already sounds mastered rather than expecting a master engineer to fix everything later on.
Does your mix need widening? Make sure you are panning your instruments. Does the mix need to sound more cohesive? Make sure you’re using proper mix bus processing techniques.
Additionally, make sure nothing is clipping. If you have channels clipping, they’ll introduce distortion into your mix that will get amplified in mastering. You don’t need to use all of the available headroom. Aim to keep your overall mix's Peak Level around -3 to -6 dBFS and keep your average level around -16 dBFS RMS (or momentary LUFS). This range will leave room for mastering a track.
You also want to ensure you’re happy with the level relationships between different elements of your mix before bouncing down to a stereo file. Once you have a stereo file (or stems if you prefer stem mastering), you won’t be able to change levels of any tracks without going back to the mixing stage of the audio production workflow.
2. Bounce down your stereo track
Once you finish your mix, the next step is to export your session as an audio file. When doing so, bounce your track down using the same settings you recorded with. So if you recorded in 24 bit, bounce it at 24 bit. If you recorded with a resolution of 48 kHz, bounce your file at 48 kHz.
Some other things to keep in mind:
Make sure you’re bouncing your file in a lossless format like AIFF or WAV. Don’t export it as an MP3, or you’ll lose the resolution of the original recording. You also want to avoid dithering or normalizing.
3. Start a new session and import your stereo mix and reference tracks
Next, you’ll want to open up a new project session and import your mix and reference tracks. A reference track is a professionally produced song representative of how you want your own track to sound. Oftentimes, musicians will have songs, albums, or artists they want their music to sound like. Track referencing is a way for audio engineers to compare and contrast the song they are mixing or mastering to songs of a similar genre or style. It’s an efficient way to track your progress and produce consistent results.
Workflow tip: Save and recall your reference tracks directly from Ozone
Ozone allows you to import, save, and recall your favorite reference tracks directly from the plug-in. Simply add Ozone to your Master Bus, open the Master Assistant Panel, and click on the “plus” icon to import an audio file from your file directory.
Once you load your reference, Master Assistant will extract its tonal balance curve and display how your track’s spectral and dynamic content (white line) compares to that of your reference track’s (blue line), so you can easily see if your work is progressing towards the sound you want.
4. Listen to the mix and take notes
If you’re new to mastering music, you may be wondering how to approach a mastering signal chain. What order should your effects be? Should you add an EQ or compressor first? Do you need special processing to upload your track to a streaming service?
There isn’t a one-size-fits-all signal chain solution for every track; each mix has its own needs. So, prior to applying any kind of processing, take the time to listen to your track on different playback systems and take notes on anything that stands out. How does the track sound on laptop speakers, headphones, studio monitors, the car, etc.? Taking notes will give your mastering workflow a sense of direction.
Regardless of your approach, however, the general philosophy is: make corrections before making enhancements. Without correcting spectral and dynamic problems first, you risk amplifying them when applying a limiter, which raises the level of the quietest parts of your signal.
As you read along, keep in mind that the following steps in this guide are processing solutions you can apply if the mix calls for it. Each section also includes ways you can optimize and speed up your workflow with the many AI-powered features built into Ozone.
Workflow tip: Let Master Assistant set up a signal chain for you
If you need direction on how to approach your mastering signal chain or if you’d simply like to speed up your mastering workflow, we recommend using Ozone’s Master Assistant. Master Assistant analyzes your track and uses tone-matching technology to effortlessly set up a signal chain that matches the tone, dynamics, and width of your mix with that of your reference tracks or whatever genre preset you select from the tonal balance target library.
From the Assistant View, you have access to intuitive controls that give you control over the main elements of your master: width, dynamics, and EQ. Each control is a macro linked to multiple parameters in Ozone’s signal chain. This allows you to make goal-oriented changes that will get you a great sounding master quickly. If you ever need to make specific adjustments, simply switch over to the detailed view for access to the signal chain and full module parameters.
5. Make level corrections with Master Rebalance if necessary
Maybe after applying basic loudness and EQ settings with Master Assistant, you notice your drums are a little quiet next to the rest of the mix. Or perhaps you receive a mix with level relationships that need to be adjusted. If you had the mix session open, you could easily reach into the mixer and change the levels of individual instruments. But with only a stereo track, your options are limited.
With the Master Rebalance module, you can take advantage of source separation technology to correct and change instrument levels at the mastering stage without needing the original tracks. Strategically boost vocals for added presence without impacting the midrange, eliminate a muddy low end by lowering bass guitar, and correct weak-sounding drums with only one module to save you hours of EQ surgery.
6. Add clarity to the low end
Mixing and mastering the low end can be complex. The bass frequencies can contain the body of an acoustic guitar, the growl of saxophones, the weight of the bass guitar, and the punch of a kick drum. With lots of instruments competing in this space, the overall tone of your low end can become muddy and unfocused. If the low end needs clarity, try the following techniques:
Try adding a high-pass filter to Side channels to attenuate bass frequencies that make their way to the left and right channels. Doing so narrows your low-end (makes it mono) and ensures it doesn’t compete with elements you have panned to the sides.
Workflow tip: Use the Low End Focus module in Ozone
You can add articulation and clarity to the overall low end with the Low End Focus module in Ozone. Low End Focus gives you control of what’s in focus in your low end (between 20 – 300 Hz) by either preserving the most prominent spectral content and lowering the less prominent content, or by bringing both extremes closer together for your low end.
A good rule of thumb is to place Low End Focus before multiband compressors––also called the Dynamics module in Ozone. This ensures that the module’s processing will be properly framed and controlled via the compressor and Dynamic EQ modules ahead of it.
Learn how GRAMMY-winning mastering engineer Emerson "Em" Mancini uses Ozone to master songs in a professional studio.
7. Correct the tone with EQ
Should you EQ or compress first? The answer depends on the needs of your song, but you generally want to focus on making corrections before making enhancements. If you hear problematic frequencies, for instance, then use subtractive EQ to remove them. The reason being, processing like compression, additive EQ, limiting, and saturation can amplify problematic frequencies making them harder to tame later on. This includes but is not limited to harsh sibilance, excessive low end, and any resonances that distract from the enjoyability of the song.
When using EQ in mastering, you want to focus on wide boosts or cuts no more than 3 dB. Your moves need to be subtle, otherwise you risk altering the foundation of the mix. Below, we’ll cover a few different types of EQ applications
Mid/Side EQ and Stereo EQ
Ozone’s EQ has different channel processing modes that allow you to EQ different areas of the stereo image. This makes it easy to surgically attenuate problematic frequencies or add stereo widening effects.
The following options are available in the dropdown menu and determines how processing is applied by the Equalizer: Stereo, Left/Right, Mid/Side
Stereo Mode applies processing to the entire stereo channel. When selected, EQ adjustments will apply to both the Left and Right channels.
Left/Right Mode separates the left and right channels so you can EQ each independently of one another. For example, if your guitar is panned hard left and you hear the unpleasant scraping sound as the guitarist’s fingers slide across the fretboard, you should isolate the frequency on the left channel and attenuate it. If you use Stereo mode (instead of Left/Right mode), attenuating that frequency will affect the entire mix rather than the left channel where the problematic frequency lies.
Mid/Side Mode separates the center from the sides. Mid is all the mono information at the center of the stereo image. Side, on the other hand, contains information that is only present in the left and right channels.
Mid/Side EQ is typically used to control what’s at the center of the stereo image. Elements at the center are usually perceived to be louder and more prominent, so you can apply EQ to the center in order to bring something forward or backward in the mix. For instance, in the course of mastering a track, you may start to change the relationship between the vocal and the rest of the mix and you may find that it's not popping out enough. With Mid/Side, instead of focusing on the sides, you can focus on the center in order to bring the vocal forward. Simply identify the frequency ranges of the vocals (say they’re anywhere between 500 Hz – 2.5 kHz), and slightly boost them in the mid channel to bring them out a little more.
Another application of Mid/Side EQ is to add a bit of stereo widening and control things on the sides. For example, you can create a sense of stereo width by applying a slight boost to the sides focused on the high frequency information or narrow the stereo width by removing a frequency from the sides.
Isolate Frequencies with Alt-Solo
A useful feature you can use to identify frequencies you want to boost or cut is the Alt-Solo function. You can click the Solo button or use the alt/option key when clicking on a node or anywhere in the spectrum to momentarily solo a specific frequency region. When you release the mouse click, alt-solo will be disabled.
NOTE: While you generally want to start with corrections before moving on to making enhancements, make sure you’re using subtractive EQ intentionally to avoid cutting important frequencies.
Workflow tip: Use the Stabilizer Module in Ozone
The Stabilizer module is an intelligent and adaptive mastering EQ that listens to your audio and reacts in real time to dynamically sculpt a professional-quality tonal balance. It will automatically detect and tame problem resonance, carve away harshness, smooth transients, and add clarity for better translation across listening environments.
8. Control dynamics and glue the mix together
To control the dynamics of your track, you’ll want to use a compressor. Three main reasons for using a compressor in mastering include:
When people mention “adding glue,” they’re referring to creating a dynamically cohesive mix that has consistent levels. You don’t want instruments or frequencies sounding out of place and distracting from the enjoyability of a song because they suddenly spike in level and overpower other elements in the mix. Punch on the other hand, refers to the impact of the track’s transients. With the right settings, you can add more impact to your transients.
Using two compressors
To achieve transparent punch and glue compression, try serial compression—a technique that uses multiple compressors in succession rather than having one compressor do all the work. Each compressor focuses on making small cuts and serves a specific function. For instance, the first compressor can have a fast attack time to attenuate the transients and even out the track’s overall level. You can then follow it up with a compressor with a slow attack that focuses on controlling the impact and punch of your track. In other words, use one compressor for glue and another for punch.
When using compression, aim for no more than a total of -3 dB of gain reduction. Subtlety is key since you’re applying compression to the entire mix; small moves become noticeable quickly.
Other types of compression
While compression controls the overall level of your entire mix, there are times when you’ll need to get surgical and tame microdynamics. Microdynamics refers to the dynamics of a frequency band (i.e., a group of frequencies such as a low end that needs to be controlled or a harsh high end that needs taming) or specific frequencies (i.e., sibilance, resonances, noise, etc.).
There are several dynamics processing tools you can use depending on the levels you need to control: compression, multi-band compression, spectral shaping, and dynamic EQ.
Multiband compression allows you to apply separate compression settings to different frequency ranges. Instead of applying compression to the entire signal like a normal compressor, you can separate the frequency spectrum into different frequency bands and apply separate compression settings to each of them. This is ideal for controlling broad frequency ranges such as the low end, mids, or the high end.
Dynamic EQ attenuates frequencies once they exceed a threshold. Dynamic EQs are different from multiband compressors in that they allow for narrower bandwidth settings which make them ideal for the surgical removal of specific frequencies such as resonances or harsh sibilance.
Spectral Shaping is low-ratio compression that is employed individually across dozens of frequency bands. You could imagine spectral shaping as a 32-band dynamic equalizer, with individual band shelf filters for every band, each automatically setting thresholds, time constants, and reduction amounts based on tuned models for each sound source. The result is a more transparent and surgical form of dynamic control that is constantly aware of the frequency content present in the incoming signal, and adjusting its processing accordingly.
While you’re free to use these tools as you see fit, it’s sometimes best to stick to the essentials. More often than not, all you need is a compressor (or two) to tame the dynamics and add punch and glue to your track.
Workflow tip: Use the Impact Module in Ozone to add Punch and Glue Compression
The Impact module in Ozone is a multiband microdynamics processor that allows you to easily add or remove transients from independent frequency bands. It reduces the complexity of working with compression parameters (threshold, ratio, attack, release, and makeup gain) by combining them into two main goal-oriented controls: the amount sliders and the BPM envelope
The amount sliders control the threshold and ratio—the degree of compression or expansion applied to each of the four frequency bands. Slide them up to increase the dynamics (expansion), slide them down to reduce the dynamics (compression).
The BPM envelope slider, on the other hand, controls the attack and release of the dynamics processor. While most compressors work in milliseconds, the Impact module has a tempo sync feature that automatically sets the attack and release times to work with the natural envelope and BPM of your track. Simply select the beat division and the Impact module will shape the envelope of your track accordingly.
9. Make EQ moves to match your reference track
Using reference tracks when mastering music can ensure that a track you’re working on is headed in the right direction. By specifically comparing things like frequency response and dynamic range you can make moves to match the aesthetic of the sound you’re after. Having a reference can also keep you from losing perspective while you're mastering. If you’re listening to your track for too long, your ears can adjust to unwanted frequencies, like high frequency build-up. Switching to your reference can quickly expose these differences and provide a much needed reset. For this step, the goal is to make EQ moves that match the spectral profile of a reference track.
The three main tools you can use for this are Ozone’s Master Assistant, Ozone’s Match EQ module, and Tonal Balance Control.
Master Assistant Tone Matching
Master Assistant gives you the ability to upload your own references, save them, and recall them within the Ozone plug-in. Once you drop in your reference track, the Master Assistant will analyze its spectral profile and set up a signal chain to match the tone. You can then use the EQ slider and the Stabilizer slider to pull your track’s spectral profile (white line) closer to that of your reference (blue line).
With Ozone, you can match any reference track to an extreme degree with an EQ that uses over 8,000 separate bands of frequencies for very precise reference matching. So if there’s an EQ profile out there that you love, Ozone will learn it and let you transfer it onto the track that you’re working with.
Verify with Tonal Balance Control
To make sure you’re not overusing Match EQ, create a custom target in Tonal Balance Control. You can use the same track you used to create your reference snapshot preset in Match EQ, but the more tracks you feed Tonal Balance Control, the better it will be able to create a smooth average response. By using Match EQ and Tonal Balance Control in tandem, you give yourself both broad and detailed views of how your song’s spectral profile compares to that of your reference. If you notice your track having too much or too little of a particular frequency compared to your reference, you can address it by controlling Ozone’s EQ module directly from Tonal Balance Control.
10. Fix or enhance the stereo image if necessary
Next you want to listen to your track and determine whether you need to apply stereo widening or narrowing with an imaging plug-in. Oftentimes a mastering engineer will want to increase the perceived width of the mix to make it feel more immersive. However, stereo widening can also introduce phase issues which lead to your mix sounding worse when played in mono.
On the other hand, there may be times where you want to narrow an element of the mix in order to create more clarity. For instance, you may want to narrow bass frequencies that made their way to the sides. Narrowing an element of the mix to mono, however, can cause you to lose information that exists in the left and right channels.
So the main takeaway is to use it subtly and only when necessary. Make sure to use a stereo imager with a correlation meter that shows your stereo file’s mono compatibility.
Workflow tip: Use Ozone’s Imager to minimize drawbacks
Ozone’s Imager precisely adjusts the stereo width for your master while minimizing the drawbacks associated with stock stereo imagers. Use it to add width to any frequency band without causing mono compatibility problems with Antiphase Prevention. And when reducing width in Imager, the new Recover Sides feature enables you to add back any side channel information that has been removed. It also has an integrated Vectorscope and Correlation Meter that gives you valuable visual feedback to help you identify mono compatibility issues so you can craft a perfect stereo balance.
11. Limit the mix
Limiting is the final and perhaps most essential step in mastering a song. A limiter allows you to increase the overall level of your song to commercial loudness while limiting the peaks from exceeding the clipping point of 0 dBfs. It’s essentially a compressor with an extreme, brick wall ratio (∞:1) that doesn’t allow any sound above the set threshold as you're increasing the level.
You want your track to sit around 0 dB so the first thing you want to do is set your output/ceiling level between -0.3 dB and -0.8 dB. This will set the brick wall threshold just below the clipping point.
From there, turn the gain up until you’re getting around -2 to -3 dB of gain reduction. If you’re using a stock limiter, any more than that can introduce noise and unwanted artifacts.
Workflow tip: Use Magnify Soft Clip in Ozone Maximizer for high fidelity limiting
The Maximizer module in Ozone has a Magnify Soft Clip feature that allows you to boost loudness while maintaining the highest fidelity. Ozone’s acclaimed IRC (Intelligent Release Control) technology lets you boost the overall level of your mixes without sacrificing dynamics and clarity.
12. Final mastering checks
You’re nearly there! Now it’s time for the final checks. For this step, you want to make sure you’re happy with the dynamic range of your master and that your loudness levels work for the genre and delivery mediums you're producing for.
Loudness targets for genres
When mastering a song, you want to aim for at least -14 LUFS integrated loudness with a -0.2 dBFS True Peak. This however varies depending on genre. For louder genres such as pop, rock, and EDM, the RMS levels should range between -6 dBFS and -12 dBFS. For quieter music such as folk, acoustic, and classical, you can go as low as -16 dBFS.
Dynamic range is the difference in dB between the loudest peak and softest part of your song. Try to keep at least 6dB of dynamic range. Any lower than that and your master will begin to lose its punch and impact. In other words, rather than sounding impactful and interesting, your song will sound like a flat wall of noise, lacking a difference between the louder and quieter parts of your song. Aim to get as much dynamic range suited for your genre within your loudness target.
Keep in mind however, that dynamic range can also vary by genre. An EDM track may sound better with a smaller dynamic range while a classical piano piece may sound better with as much dynamic range as possible.
Another important consideration is the delivery medium you're mastering for. Different platforms have loudness standards and constraints you need to take into account. For instance, if you’re track is not loud enough, streaming platforms will apply their own limiter which can change the way your music sounds. Mastering for streaming is different from mastering for vinyl. Make sure you do your homework.
13. Bounce your master
With everything ready to go, your song is ready to be exported into a stereo audio file you can release to the world. Select the track to be bounced as a lossless file (AIFF or WAV) and an .mp3 file. Then you’ll want to make sure the track is bouncing at 16 bits and a sample rate of 44.1kHz.
With the file format, resolution, and sample rate selected, you’ll finally dither your track. Proper dithering ensures no audible loss of quality when you convert to lower bitrates.
NOTE: make sure you dither your audio only once!
Workflow tip: Dithering with Ozone
Ozone includes a comprehensive set of dithering tools to help you prepare studio-quality audio for different delivery formats. The Dither panel includes iZotope’s MBIT+ dither algorithm along with a unique set of meters to offer a complete view of the conversion process.
Start Mastering Music
Now you have the foundations of how to master a song! Whether you’re a pro mastering engineer or mastering a track for the first time, mastering can be a complex process––but it doesn’t need to be. We hope this guide and the intelligent tools and ways to use them outlined above offer some guidance on the mastering workflow. Please be sure to check out more articles about audio mastering for more helpful techniques.