So here we are at Part 4! If you’ve read all of these from the start then well done and I hope they’ve been useful. I always found that reading a single well written blog or book chapter on audio helped me more than hundreds of hours of Youtube stuff. And I still go back to Bob Katz’s ‘Mastering Audio’ book about once a year for a flip through to refresh myself on stuff or dive deeper into something that I’m currently into.
But let’s get on with it and get into a very important part of mastering, getting stuff LOUD. Now I’m very much in the ‘quality over loudness’ camp but let’s be real, people like stuff loud. So our job is to get loudness without compromising the quality of our carefully recorded, mixed and produced material.
We'll also discuss the essential considerations for exporting masters for distribution, ensuring your music reaches its audience with the highest quality possible. This is something I’ve touched on in previous posts and something that doesn’t get enough attention in my opinion. I regularly get contacted by artists, producers and pressing plants who are asking for last minute help because someone has not delivered the correct file types or missed a crucial part of the distribution process.
Getting an amazing sounding master is a mighty task in itself but it can all fall flat at the final hurdle if it’s not delivered in the correct sample rate, bit depth and/or format. It’s not very glamorous or even creative, it’s purely administrative BUT it is an essential part of the mastering process!
So let’s start with the fun stuff, loudness!
1. Compression:
Maybe the most complicated of the dynamics processing we’re going to talk about but it’s mostly used earlier in the chain than clipping and limiting so let’s dive into it.
Compression is a dynamic audio processing technique used to control the dynamic range of audio signals. Dynamic range refers to the difference between the loudest and quietest parts of a sound. By applying compression, you can reduce this range, bringing quieter sounds up in volume while preventing louder sounds from peaking and distorting.
The aim of compression in mastering is usually control and glue. Controlling any unruly peaks and giving a sense of glue. The ‘glue’ is a term often used for a sense of cohesion that comes from bringing down the loudest parts and bringing up the quietest parts of a mix so all the elements meld together in a pleasing way (if done correctly)
So let’s look at the key components of a compressor so you know how each setting affects the sound.
Threshold: This sets the level at which compression begins to take effect. Any signal above this threshold will be affected by the compression.
Ratio: The ratio determines how much the signal above the threshold will be reduced. For example, a 4:1 ratio means that for every 4 dB the input signal exceeds the threshold, the output signal will only increase by 1 dB.
Attack and Release: These parameters control how quickly the compressor responds to changes in the input signal (attack) and how quickly it returns to normal after the signal drops below the threshold (release).
Makeup Gain: Since compression reduces the overall level of the signal, makeup gain allows you to boost the volume to compensate for this reduction.
Using Compression for Loud Masters
Achieving loud masters while maintaining clarity and dynamics requires a thoughtful approach to compression. Here are some tips to help you make the most of compression in mastering:
Subtle Compression: Aim for transparent compression that enhances the dynamics without squashing the life out of the music. Start with a low ratio (e.g., 2:1) and adjust the threshold to gently tame peaks. Adjust this while paying careful attention to the ‘life’ of the mix. We’re not aiming to solve the whole loudness puzzle here, just a small amount of peak reduction and glue to allow the following processors to do their job better.
Try adjusting the attack of the compressor while listening to the initial transients. Ideally we want the attack to be slow enough to let a little of the transient through to preserve the punch and energy but fast enough to actually do some reduction. It’s a fine line to tread so take your time listening to various settings. I suggest using more extreme settings at first to train your ear to the effects of compression before backing them off and getting more subtle and musical settings.
Parallel Compression: Parallel compression involves blending a heavily compressed signal with the original uncompressed signal. This technique can add density and punch to the mix while preserving transient detail. This is often used more so in the mix stage but can be useful if used sparingly during mastering, especially for more loud and aggressive genres of music.
Automation: Don't rely solely on static compression settings. Utilise automation to adjust compression parameters dynamically throughout the track, especially during sections with varying intensity.
One example would be to boost the input gain of a compressor during a chorus to give 1 dB of gain. This would not only give some volume but the added gain would drive the compressor slightly harder resulting in a thicker sound.
Or you might choose to back off the threshold during a verse so it sounds more open and dynamic.I often make real time changes during a master, either with compression gain, threshold or attack time.
So there’s a few tips to help you get started with compression, remember to start subtle and go from there. And don’t forget that this is just one part of the loudness chain, you don’t need to get too much happening here, a small amount that sounds good will really help the following processors.
Examples of Plugins: Affordable and widely used compressor plugins include the FabFilter Pro-C 2, Waves SSL G-Master Buss Compressor, and Native Instruments VC 76. I like a good Fairchild emulation too, there’s lots out there, so check them out!
Pitfalls to Avoid: Over-compression can result in a loss of dynamics and a "squashed" sound. Use compression judiciously and experiment with different attack, release, and ratio settings to maintain clarity and punch.
2. Clipping:
Don’t let your music clip! Isn’t that what you’re always told?
So why am I recommending clipping in mastering, surely we want to avoid distortion right? Well, while traditionally seen as an undesirable form of distortion, when used judiciously, clipping can add energy, excitement, and loudness to your tracks. The harmonic saturation created with tiny amounts of distortion along with the peak reduction can actually really help a master achieve greater loudness.
Understanding Clipping
Clipping occurs when the amplitude of an audio signal exceeds the maximum level that can be represented by the recording or playback system. As a result, the waveform is "clipped" or flattened at the peaks, causing distortion. While large amounts of this sound terrible, very small amounts actually sound quite pleasing and can thicken up an audio signal by adding extra harmonic information.
Using Clipping Effectively
When used carefully clipping can be a powerful tool for achieving loud masters with character and impact. Here's how to use clipping effectively in mastering:
Soft Clipping: Rather than allowing the signal to clip abruptly, use plugins that offer soft clipping algorithms. Soft clipping rounds off the peaks of the waveform more gently, resulting in smoother distortion characteristics.
Subtle Application: Apply clipping subtly to avoid excessive distortion. Start with conservative settings and gradually increase the amount of clipping until you achieve the desired level of loudness and character without compromising the integrity of the mix.
LF Clipping: Low Frequency clipping can be very useful in certain genres of music. This frequency focused clipping will target only the low end, most commonly reacting to a kick and/or 808. This not only adds some subtle thickness but can also take some pressure off the following limiter by reducing the peak level.
Monitor Carefully: Keep a close eye (or ear) on the waveform and listen for any artefacts introduced by clipping. Avoid clipping essential elements of the mix such as vocals or lead instruments, as this can result in audible distortion.
As mentioned with compression, if you're new to using clipping, try it at some more extreme settings to train your ear to the sound and then back it off and work with subtle amounts.
When used with care and intention, clipping can be a valuable tool for mastering engineers and independent artists seeking loud, impactful masters. By understanding the principles of clipping, its effects on sound, and how to apply it effectively, you can add character, warmth, and energy to your tracks while pushing the boundaries of loudness. Experimentation and careful monitoring are key to harnessing the full potential of clipping in mastering
Examples of Plugins: My 2 favourite clipping plugins are SIR Tools Standard Clip which has a great interface and TDR Limiter 6 GE which has a great clipper module. The LF clip option allows you to only clip the low end, usually focusing on a kick, which not only adds some nice saturation to the kick but ensures it doesn’t hit your following limiter as hard.
Pitfalls to Avoid: Too much clipping can lead to harsh distortion and artifacting, so use it sparingly and in moderation to avoid compromising the integrity of your music.
3. Saturation:
Saturation is a powerful but dangerous tool in the mastering engineer's toolkit! It offers a way to add warmth, character, and harmonics to audio signals but can quickly degrade your audio if not used with care! When used effectively, saturation can help achieve louder and more dynamic masters while imparting a pleasing analog-like quality to the sound.
So what exactly is it?
Saturation is a form of distortion that occurs when an audio signal exceeds the linear response range of an analog or digital system. Unlike clipping, which results in harsh and abrupt distortion, saturation introduces subtle harmonic distortion that can enhance the richness and warmth of the sound.Like all of the processing we’re looking at today, a little bit can sound really good but if pushed too far it can quickly bloat or distort your mix. Tread carefully!
Effects of Saturation
Saturation can have several beneficial effects on audio signals, including:
Increased Harmonics: Saturation adds harmonic content to the original signal, enriching its tonal quality and adding depth and dimension to the sound.
Transient Smoothing: Saturation can soften the transients of audio signals, resulting in a more cohesive and smooth sound while retaining overall clarity and punch.
Loudness Enhancement: Saturation can increase the perceived loudness of audio signals without necessarily increasing peak levels, allowing you to achieve competitive volume levels while preserving dynamic range.
Using Saturation Effectively
To harness the power of saturation in mastering, consider the following techniques:
Analog Saturation Emulation: Use plugins or hardware processors that emulate the characteristics of analog saturation, such as tape saturation or tube warmth. These plugins often offer adjustable parameters such as saturation level, bias, and harmonic distortion characteristics.In effect they recreate the imperfection of analogue components (which we humans actually quite like the sound of).
Multiband Saturation: Apply saturation selectively to different frequency bands using multiband processing techniques. This allows you to target specific areas of the frequency spectrum that may benefit from added warmth and harmonics, while leaving other areas untouched.For instance you could add saturation to the high ids to bring out the main vocal or saturate just the low end to thicken up your kick and bass.
Blend with Dry Signal: Use parallel processing to blend the saturated signal with the dry (unprocessed) signal. This allows you to control the amount of saturation applied to the mix, preserving clarity and dynamics while adding richness and warmth.Especially handy when you find a saturation sound you like but it’s a bit too heavy handed for the mastering stage, you can blend in 10 or 20% for example to add a subtle lift to your mix.
Experiment with Saturation Types: Explore different types of saturation, such as tape, tube, and transformer saturation, to find the right character for your mix. Each type of saturation imparts its own unique sonic characteristics, so don't be afraid to experiment and find what works best for your music.
Monitor Carefully: As with any form of processing, it's essential to monitor the effects of saturation closely and listen for any artefacts or unwanted distortion. Use A/B comparisons and reference tracks to ensure that the saturation enhances the overall sound without detracting from the mix.I’m going to repeat myself a lot on this topic, but careful listening and subtle use of the effects are key to achieving a great sounding master.
Examples of Plugins: There’s lots of different types of saturation so think carefully about the kind of sound you want and choose accordingly. There are dedicated tube saturators and lots of dedicated tape saturation plugins but if you’re new to this a good place to start is with the Soundtoys Decapitator. Fabfilter Saturn is also really good but it’s very complex and can take a while to get a subtle enough sound for mastering duties.
Pitfalls to Avoid: Over-saturation can lead to a muddy or overly distorted sound. Use saturation subtly and in moderation to enhance the character of your music without overpowering it.
4. Limiting:
Chances are that you’ve probably already used a limiter and have a decent idea of how it works but let’s have a look at the last piece of the loudness puzzle. A limiter should always be last in your chain, but if you’ve used saturation, compression and clipping carefully then hopefully the end limiter won’t have too much work to do!
A limiter really is the ultimate tool for controlling peaks and maximising loudness while maintaining the integrity of the mix. But like everything else (and I know, I’m repeating myself a lot) it has to be used carefully, otherwise your mis will sound bloated, distorted and flat.
Understanding Limiting
A limiter is a dynamic audio processor designed to prevent the amplitude of an audio signal from exceeding a specified threshold level. Unlike compression, which reduces the dynamic range of the signal, limiting imposes a hard ceiling on the peaks of the waveform, preventing them from exceeding the threshold level.
Whereas a compressor brings down peaks, a limiter pushes your track up into a ceiling. This increases loudness but also reduces dynamic range. The trick here is balancing loudness with dynamic range, if you just slam your mix into a limiter it will get louder but start sounding flat and lifeless.
Using Limiting Effectively
To harness the power of limiting in mastering, follow these tips:
Place the Limiter at the End of the Signal Chain: Position the limiter as the final processor in your mastering chain, after EQ, saturation, compression, and clipping. This ensures that the limiter acts on the fully processed signal, allowing you to control peaks and maximise loudness while preserving the tonal balance and dynamics of the mix.
Set the Threshold and Ceiling: Adjust the threshold parameter to determine at which point the limiter begins to take effect. Set the ceiling parameter slightly below 0 dBFS to prevent clipping and ensure that the limiter effectively controls peak levels without introducing distortion.
There’s a lot of debate as to where to set your ceiling. Spotify asks for a -1dB ceiling but in practice most professional mastering engineers set their ceilings closer to 0dB, anywhere from -0.5 to -0.1. This little bit of extra headroom helps with achieving louder punchier masters so is the norm for modern genres of music but not as necessary for classical, ambient and jazz types of music.
Adjust the Release Time: The release time parameter controls how quickly the limiter responds to changes in the input signal. Use a moderate release time to allow the limiter to react smoothly to transient peaks while avoiding pumping or breathing artefacts.
Use Oversampling: Many limiters offer oversampling options, which help mitigate the unwanted effect known as aliasing. Enable oversampling to ensure optimal sound quality and minimise aliasing artefacts.
This is quite a complicated topic to get into right now but here’s a link to an article by Fabfilter about oversampling, specifically when used in their Pro L2 limiter - https://www.fabfilter.com/help/pro-l/using/oversampling
Monitor Gain Reduction: Keep an eye on the gain reduction meter to ensure that the limiter is not excessively squashing the dynamics of the mix. Aim for moderate gain reduction levels to achieve loudness without sacrificing dynamics or introducing audible artefacts.
Some limiters will have a ‘delta’ function to let you hear exactly what the limiter is removing and some have a gain match function so you can A/B between the non-limited and limited signal at the same volume.
And seeing as though this is my last chance to say it, I’m going to repeat myself one last time! Use limiting carefully, really take your time listening to the effect your limiter has on the sound of your master. Push it a little, then back it off, get used to the way it reacts and find that balance between loudness and dynamic preservation. Good luck!
Examples of Plugins: Affordable and widely used limiters include FabFilter's Pro-L 2, and IK Multimedia's Stealth Limiter. My favourites are DMG’s Limitless for its transparency and the TDR Limiter 6 Ge for the extra Clipper and High Frequency Limiter modules which give you loads of control of your signal.
Pitfalls to Avoid: Over-limiting can result in a loss of dynamics and a "pumping" or "breathing" effect, where the volume of the music fluctuates unnaturally. Use limiting conservatively and ensure that you're not sacrificing dynamics for loudness.
Exporting Masters for Home Distribution:
I told you that we’d get around to this important yet administrative part of the mastering process. Even though it’s not the most fun, if you’re a budding mastering engineer you have to enjoy structure and organisation to some degree, it’s a key part of file management. Artists, producers and labels rely heavily on you to have quick access to all files they may need and you’ll often be asked to re-send or remaster things at short notice as certain opportunities arise. If you’re disorganised and can’t find files quickly you’ll waste a lot of your own and other people's time.
File Formats: The first thing to know! Different distribution channels have specific requirements regarding file formats and encoding parameters. Familiarise yourself with the preferred file formats for each platform, such as WAV or FLAC for digital downloads and DDP for physical media. Commonly accepted files for Cd production and uploading to digital distributors are 44.1kHz & 16 bit Wav files.
Streaming Services: Your streaming masters should usually be in 44.1_16 as stated above but beware of some distributors who will say that they accept higher resolution files.
Just because they ‘accept’ higher resolution files doesn't mean they distribute higher resolution files. They simply accept them and then down sample them automatically. Don’t let them do this! You’re giving them free reign to adjust your carefully mastered tracks, without being checked by a human!
The exception is uploading high res files to a high res service that actually streams your tracks in higher resolution without adjusting them. Tidal, Apple and some more offer this service but you end up having to upload 2 different versions (and paying twice) to upload normal and then high res versions.
Vinyl Masters: Mastering for vinyl presents unique challenges due to the physical limitations of the medium, such as groove spacing and frequency response. When compiling vinyl masters, consider factors like track sequencing, spacing between tracks, and overall loudness levels to ensure optimal playback quality on vinyl records.
Vinyl masters should be exported as complete sides without any limiting and at the sample rate and bit depth of the mastering session (usually 48_24 or higher)
PQ Sheets A PQ (Production Queue) sheet is an accompanying document which outlines all relevant information about the vinyl masters which helps the disc cutting engineer cut a great sounding record.
It has information such as no. of songs, song start and end times and any other relevant information that an artist or engineer may need to tell the cutting engineer about. For instance - ‘Between song 2 and song 3 there is an interlude with no silence, this is intentional’.
It also contains contact information so that if there are any issues the cutting engineer can quickly get hold of someone to ask any relevant questions.
DDP Files: When preparing masters for CDs, DDP (Disc Description Protocol) files are commonly used to encapsulate all the necessary data for replication. As well as the actual mastered tracks, a DDP contains start and end points, track titles, and ISRC codes.
A DDP is laid out as a complete project so all gaps between songs are preserved exactly as set out. This is really handy for albums where the space in between songs, fade outs and any interludes are important and have been sequenced carefully.
Wrappin’ It Up
In conclusion, achieving optimal loudness levels in mastering requires a combination of compression, clipping, saturation, and limiting techniques. By understanding the role of each tool and using them judiciously, mastering engineers can create loud and great-sounding masters that stand out in today's competitive music industry. Experimentation, practice, and careful listening are key to mastering the art of loudness while preserving the integrity and dynamics of your music.
Additionally, mastering the intricacies of exporting masters for home distribution ensures that your music reaches its audience with the highest quality possible across various platforms and formats.
As always, I hope that’s been interesting and helpful for you. Give me a shout with any questions or if there’s any specific areas of mastering you’d like to learn about. And if you’d like to chat about mastering your music for any format, get in touch anytime and let’s talk about how we can get your project out into the world.
Click the link to go to my contact page - https://www.raretonemastering.com/contact
Speak soon!
Ben
P.s. if you like all things analogue, mastering & vinyl related please go over and follow my Youtube & social media accounts where I regularly make videos about mastering and cutting records!
My Instagram - www.instagram.com/raretonemastering
My Youtube channel - https://www.youtube.com/channel/UC1eTArh9eYA0Br2hJL0lGEg
My TikTok - https://www.tiktok.com/@raretonemastering
Links to Plugins mentioned:
Fabfilter Pro C2 - https://www.fabfilter.com/products/pro-c-2-compressor-plug-in
Waves SSL G Bus - https://www.waves.com/plugins/ssl-g-master-buss-compressor
SIR Standard Clip - https://www.siraudiotools.com/StandardCLIP.php
TDR Limiter 6 GE - https://www.tokyodawn.net/tdr-limiter6-ge/
Soundtoys Decapitator - https://www.soundtoys.com/product/decapitator/
Fabfilter Saturn - https://www.fabfilter.com/products/saturn-2-multiband-distortion-saturation-plug-in
Fabfilter Pro L2 - https://www.fabfilter.com/products/pro-l-2-limiter-plug-in
IK Stealth Limiter - https://www.ikmultimedia.com/products/trstealthlimiter/
DMG Limitless - https://www.dmgaudio.com/products_limitless.php
Native Instruments V 76 - https://www.native-instruments.com/en/products/komplete/effects/vc-76/
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