An Introduction To Mastering

The following post is an article that I wrote earlier last year that never ended up seeing its publication. Looking back on it now however I can see merit in some of the ideas discussed so I have placed it here for anyone who may be interested and may come back to it with my thoughts or potential revisions at a later date:

An Introduction To Mastering

Alex Mader - 31st January 2018

To many people mastering is seen as something of a “dark art”. Even at the professional level a lot of artists and producers know little about what it involves and why it matters, so hopefully this article will help to shed some light on the subject and share what makes it such a deep and interesting stage in the production process.

What is Mastering?

At the basic level, mastering is the final stage in the music production before release and distribution. It involves the preparing a release by ensuring it sounds its best on all platforms and presenting the artists creative intentions in their best light. This can involve providing an extra layer of polish to a release, ensuring consistency across a number of tracks and optimizing it for streaming, CD, vinyl, or whatever release format the client might choose. Mastering engineers perform a delicate balance between the application of advanced technical skills, and the sensibility to understand and respect the creative intentions of the artist.

It’s much more than simply making a track louder.

Why is it important?

Mastering is important as it provides the final opportunity to make any adjustments or corrections before release. It’s about transcending the limitations of the mix or whatever playback system a release may be heard from and making sure that it sounds its best no matter the situation. A good mastering engineer pays attention to things such as tonal balance and dynamics and knows when to manage or enhance these elements in order to create the best version of the artists intention as possible.

Why is it interesting?

Mastering also provides a number of unique creative and technical challenges. Mastering engineers need to be able to balance their own taste with that of their clients, enhancing what is already there while bringing a fresh perspective. Mastering engineers also work with some of the most advanced and powerful tools available and have a unique perspective towards subtlety and transparency.

Can Anyone Do It?

Mastering is a skill that anyone can learn. While the reliability of results is greatly dependant on a quality listening environment, processing tools and of course experience, anyone can learn and perform the fundamentals. These days mastering software is more powerful and affordable than ever and there are an abundance of online resources that can teach everything from the basics to more advanced techniques.

What’s important to remember though is that mastering is more than just a technical process. While the technical skills and techniques involved in mastering can help you become a better producer or engineer, it's a very different skill to be able to come to a project you are unfamiliar with and provide the kind of guidance and care that is expected at a professional level. It takes many years and many, many projects of experience to develop your ear as a professional mastering engineer but if you can learn to listen, both to the mix and to your clients, you are on the right track.

Where to get started?

As with anything the best way to get started it to get your hands dirty! Grab some of your favourite records and see what you can do to make them sound better. It doesn't matter what tools you use, just take the opportunity to experiment and see what different processes do to the way a song sounds and feels.

There are heaps of great mastering tools out there and an abundance of online tutorials and forums where you can ask questions and learn. Once you start to develop your “ear” and a sense of what you are doing remember to always experiment with new techniques and ideas.

And don't be afraid to learn from the professionals!

Seek out engineers online and especially your local area and don’t be afraid to ask them questions. No one who doesn't love what they do lasts very long in this business, as long as you are polite and respectful of people's time you will be surprised how much they can be willing to share. Good luck!

Deep Thoughts on Filters: Part 1

With that in mind the point I wish to make for consideration is to try and keep the phase distortion of high-pass filters at hand when choosing to use them. All (non-linear) high-pass filters introduce significant phase distortion at and around their cutoff frequency by nature of their very design. This is true for both analog and digital filters and may be a topic of conversation for a later date. The amount of distortion is relative to the slope of the filter, the stronger a filter affects frequencies below its cutoff point the greater its phase distortion. While there are a number of different designs of filters, each with their own filter shapes and respective phase distortion, none can completely eliminate this effect and mainly just seek to change the behavior of this phase distortion in a way that is more pleasing for certain applications.

The most common place I find the issues with high-pass filters come into play is when removing sub frequency material from bass instruments or the master bus of a mix (hence the bad pun in this title). While many of the following comments are true in all applications of HP filters, this is the area where I find their side effects most problematic.

Firstly you have to be very careful when making the decision to do any kind of equalisation or processing on the master bus, while it can certainly be a powerful tool, it is important to remember that it can only ever affect the sum of the total mix and not individual elements before they come together at the master bus. In other words if you are high-passing your mix to get rid of excess sub frequencies you should be aware that those frequencies are still interacting earlier on in the chain and may be triggering compression, saturation, or other processing in an undesirable way.

This may seem obvious but it is important to consider that if you are correcting a problem on the master bus it is almost always better to find that problem earlier in the signal chain and fix it there. This could mean placing a high-pass filter on only the elements of the mix that are providing too much bass, or even simply turning them down. The point is to minimise the application of any processing only to where it is necessary.

With that in mind the point I wish to make for consideration is to try and keep the phase distortion of high-pass filters at hand when choosing to use them. All (non-linear) high-pass filters introduce significant phase distortion at and around their cutoff frequency by nature of their very design. This is true for both analog and digital filters and may be a topic of conversation for a later date. The amount of distortion is relative to the slope of the filter, the stronger a filter affects frequencies below its cutoff point the greater its phase distortion. While there are a number of different designs of filters, each with their own filter shapes and respective phase distortion, none can completely eliminate this effect and mainly just seek to change the behaviour of this phase distortion in a way that is more pleasing for certain applications.

Image source: Ian Stewart: CENTER THAT SUB! (A GUIDE TO MONOING YOUR LOW END) - see footnotes

The point is that when you use a high-pass filter, it is important to think beyond just the curve represented in your plugin or DAW and really listen and focus on the way that the filter is interacting with the phase near to the point you have placed the filter. For example sometimes a filter can cause the transient of the kick to move forward or back in a mix or can change the way that a mix sounds in more than just the reduction of certain frequencies would suggest. The way that the phase distortion of a high-pass filter will interact with a full mix can be hard to predict and it would be inappropriate to recommend anything other than paying attention when using them and taking the time to make A/B comparisons between the processed and unprocessed signals.

By no means am I recommending against high-pass filters, again they are a powerful and versatile tool. What I am saying is that they need to be more than an automatic decision. Where and how you chose to use them can have a profound effect on the rhythmic and tonal nature of a mix if you are not careful. Being aware of this fact is an important skill to develop and learn, something that I myself am often practicing. Once you are aware of how filters can interact with the phase of a mix it can even become a viable technique to deliberately chose some filters over others specifically for their phase interactions that you might deep suitable for a certain sound or effect.

Again I may chose to get into further detail in a later post but for now maybe play around with some different filter settings on your master bus and see what happens. If you are interested in learning more I highly recommend starting with this excellent article by Ian Stewart (1). Good luck!

Footnotes:

(1) Ian Stewart. Center That Sub! (A Guide to Monoing Your Low End) - Blog - Flotown Mastering [Internet]. 2018 [cited 2020 Jan 6]. Available from: http://ianstewartmusic.us/blog/center-that-sub

Analog Limiting In-The-Box

There are an abundance of excellent digital limiters out there but sometimes you want something that just feels a little more old school. The following are a couple of my personal recommendations for plugins that provide a bit of that analog flavour to buses, groups or whatever you throw at them.

Ableton Colour Limiter:

This limiter comes as part of the Creative Extensions pack made available to all Ableton Live 10 users shortly after launch and has the same excellent build quality and sonics as the native Ableton effects. This limiter provides a distinctively distorted and larger-than-life character when pushed but can also be used as a more subtle peak limiter. As the range of the meter would suggest I believe this limiter is best used for creative effects and excels at this task.

D16 Frontier:

This limiter provides a few more precise controls, including a built in soft clipper that makes it well suited to characterful bus or group limiting. The ability to control the input sidechain can create some interesting effects and the variable release definitely helps maintain a more analog-like limiting behaviour.

Limiter No.6:

Limiter No.6 has had an interesting development history. Currently there are two versions available; the original release which is freely available and the version published by Tokyo Dawn Labs that provides a number of extra features for a very reasonable price. More than a single limiter this plugin chains a number of powerful tools in series providing very precise control over final sound, allowing both characterful and transparent final limiting.

Slate Virtual Tape:

Not exactly a limiter or clipper but none the less an excellent tape saturation emulation that is perfect for creating that classic overdriven tape sound when desired. Simply push the input and you can add colourful distortion and soft clipping to drums or mixes. With plenty of controls and extra features this is often my go to tape saturation tool.

Waves API 2500

An excellent compressor from API and Waves. This particular emulation can perform as a robust clipper when overdriven with analog mode enabled. Excellent for squeezing that extra bit of headroom before a final limiter or adding a bit of extra saturation or edge to drums or vocals in addition to its excellent versatility as a VCA compressor.