How to critically listen to and analyse audio – what aspects of a mix do I look out for?
Being able to objectively listen to and analyse your audio is a very important milestone for audio engineers. How do we know what characteristics to look out for when listening? And more importantly how do we apply those changes?
Arguably one of the most important yet overlooked tools for the mixdown process is reference material. Often working on a project for lengthy periods of time gives you a subjective outlook, and having reference material is a great way to “reset your ears”. You will be able to make much more accurate judgements over the frequency response, levels and overall balance of a track – if you have something to compare it to.
It is a good idea to build up an archive of tracks in various genres that you feel are representations of audio engineering at its best, take notes as to how they achieved certain elements, where certain sounds were placed in the stereo field, and then apply them to your mixes. Get a feel for the amount of energy in the different frequency bands, and how those frequencies react to your studio space. It is also very useful to get a reference of the difference characteristics that your reference material has both in headphones and through your speakers.
In the contemporary music sphere, a huge portion of popular music has a melting pot of influences from electronic to acoustic backgrounds. A pop song with a heavy electronic/techno based backtrack, will obviously benefit profoundly when compared and referenced against a techno track.
The increase in loudness is drastically reducing headroom across the board
Another critical tool for the listening and analysis process, is taking into account the overall balance of the track. This refers to both the levels and placement of the instruments in the arrangement as well as the overall frequency response of the material.
Human hearing is adaptive, if you spend time in a noisy environment your ears adapt to focus in on closer sounds, and in turn your ability to visualize a full stereo image becomes difficult and you lose dynamic sensitivity. It’s important to train your ears, and like an athlete would stretch before they compete, an engineer should spend time in a quiet environment before a full day of mixing or mastering. Another very good idea is to spend time in nature, close your eyes and focus in on the ambient sounds, condition your brain and ears to get immersed in stereo space.
Similarly, If you have been listening to music with a heavy bass-boost for a long period of time, your ears start to lose their low-end sensitivity and in turn your mixes will sound like they have a bass-boost applied, or a total cut of the low-end for that matter.
A handy technique for pinpointing the “tonal domain” of a sound in your reference material, is to isolate frequency bands using an EQ, then sweep the frequency until you find the band of frequencies that that sound occupies.
Dynamic range is where it becomes a bit more tricky for the untrained ear or producers who are in a sub-par acoustic environment, thankfully there is a variety of plugins that make life a little easier when trying to pinpoint the dynamic range in your material. Some plugins give you a reference of what you should aim for, although not all material is the same and therefore we go back to our library of reference tracks.
More experienced engineers can often tell whether material has high or low dynamic range, although being able to accurately estimate the exact figure is tough. The human ear is also subject to changes in perceived dynamic range, that’s why it’s important for even the most experienced engineers to use analyzers alongside a library of reference material.
Without getting too deeply entrenched in the “loudness war” it’s evident that the loudness on recorded material has been steadily increasing over the past few decades. The increase in loudness is drastically reducing headroom across the board, so most good audio engineers do agree that things are getting out-of-hand. However some iconic engineers use loudness to their benefit, a large portion of hard-rock and some of the “edgier” genres make use of driving the audio right into the clipping range, to create a harder-hitting sound.
Make use of a reliable LUFS Loudness meter, and compare your mix to your reference material.
A well-produced track should have all of the above characteristics, but it should also have movement or “tension and release”. Pay attention to how the levels, balance and dynamic range change in different parts of an arrangement, generally speaking the chorus will be the main focus and in turn will usually have an increase in energy in that section. How is that increase in energy being achieved in the reference material? Are the levels being boosted, or are more instruments being introduced?
The concept of “sonic matching” is using analyzers and visualizers to accurately match two sound sources. This is a very helpful technique for those with untrained ears or even just as a quick reference for professionals. There are various plugins that offer the ability to create sonic fingerprints of incoming audio to analyze and compare alongside another incoming signal, even better some offer the ability to create multiple fingerprints for different parts in the track as an example. This technique makes comparing almost all of the above-mentioned characteristics much easier, as you’re not relying solely on your ear, which is adaptive.
As mentioned above, referencing is incredibly important in the production, mixing and mastering process and any tools added to an engineer’s arsenal to do so, will benefit them greatly! It’s also important to remember that reference material doesn’t always have to be your favourite genre or artist, we can learn a large deal from listening to material that is out of our comfort zone, as professional mixing and mastering engineers often get tasked with working on material that’s out of their prefered genre, again having the ability to see or hear things objectively is the key.
Here’s a list of some of my current favourite reference tracks, as you can see there’s a wide variety of genres and styles, from hard to soft and experimental to electronic.
A Perfect Circle – Talk Talk
Jamiroquai – Automaton
Daft Punk – Fragments of Time
Shpongle – Tickling the Amygdala
Deadmau5 – Polaris
Astrix – Deep Jungle Walk