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Sonic Visualization: Is A Picture Worth A Thousand Words In Audio?

The value of thinking about – and looking at – the mix in a graphical way. Anything that can help us visualize sonic concepts can enable us to better understand the nature of the mix and produce consistently high-quality results.

It is said that “a picture is worth a thousand words” and nowhere is this more applicable than when trying to teach complex concepts.

A graphical depiction can often convey an idea better, and quicker, than a whole bunch of words. This is because our brains are mainly image processors, not word processors; the part of our brain that processes words is actually very small in comparison to the part that processes visual information.

Therefore visual cues help us to better store and retrieve complex information.

Bearing this in mind I’ve been exploring various ways of representing key audio concepts and terminology visually. This invariably involves a certain degree of simplification but I think the results are a useful weapon in the battle against incomprehension.

Let’s start by looking at a simple way to represent the frequency content of a single sound, such as a kick drum, shown here against a vertical axis denoting frequency (Figure 1). On the left is a representation of a kick drum that has been miked in a standard way, with a single microphone poking through the hole in the front skin.

Here we can see there is slightly more energy in the bottom and top of the sound (i.e., the thud and the click) than there is in the middle – quite common when close miking a kick drum. The right side of the image represents the same signal after a little EQ has been applied, in this instance the bottom end has been enhanced while the lower and upper mid range frequencies have been reduced slightly to give that classic kick drum sound.

EQ isn’t the only way we affect the frequency content of sounds so let’s take a look at some other methods (Figure 2).


On the left is a representation of a snare drum that has been miked up in standard manner – a single mic above the top skin. In the middle is the same snare with a high-pass filter applied, as indicated by the fade (which denotes the gradual reduction in the lower frequency content). On the right is the same snare after compression has been applied. In this instance the compressor is limiting not just the dynamic range of the snare (which is difficult to depict in a static image) but also it’s frequency content, resulting in a tighter and punchier sound at the possible expense of some of the finer detail.

Now that we’ve established a simple way to visually represent the different sounds, and the ways in which we can affect them, let’s take a look at a full drum kit. The kit as a whole has the widest frequency range of just about any instrument (with the possible exception of the pipe organ), from the low thud of the kick drum to the fizzy sparkle of the cymbals.

It comprises multiple elements that all need to be miked up in a way that enables us to treat each individual sound in relative isolation such that when they are combined, they complement each and work together as a whole. If we take a standard four-piece drum kit, miked up in a standard way (i.e., a single mic on each drum with a pair of overheard mics), and just bring up all the faders, it might “look” something like Figure 3.

I’ve now added panning information to the horizontal axis to denote the positioning of the sounds within the stereo field (at the moment everything is panned centrally). The one thing that this depiction makes obvious is the clutter that occurs where the sounds overlap each other, particularly in the mid range where the kick, snare and toms all produce sound energy.

This is a common cause of “muddiness” in the drum mix – something which can quite easily be addressed with a little EQ and panning (Figure 4). Here we can see that a bit of EQ has been used to bring the bottom end of the kick drum out, the kick has also been compressed and a low pass filter has been applied. The snare has also been compressed and a high pass filter has been used to tame the lower mid energy. The toms have been EQ’d and panned to create some space for the snare and mimic their physical placement in the kit. The cymbals (or overheads) have been high passed and panned wide to give the top of the kit a nice sense of width.


Overall you can quite clearly see that the processing, while quite subtle, has created space for each individual element of the kit so they can be clearly heard but also so they work together and complement each other. This avoids the muddiness that can so easily bog down the drum sound and gives the kit the clarity and definition that will help it to sound good, even in the busiest of mixes.

Speaking of which, let’s take a look at other common mix elements in the form of a simple three guitar set-up, i.e., bass, rhythm and lead guitars (Figure 5).


This depiction shows the potential for a messy sound in the lower mid range where all three instruments produce energy. We can also clearly see the masking that commonly occurs when the fundamental frequencies of the guitar overlap and obscure the harmonics of the bass.

Guitars also tend to have a pronounced low end as a result of the use of directional microphones in close proximity to speaker cabinets which exacerbates the proximity effect. Thankfully this can all easily be fixed with high-pass filters and a little panning (Figure 6).


First, the bass has been compressed, which helps tighten it up and enables it to rumble away at the bottom of the mix without jumping out or dipping down. The guitars have been high passed and panned, which not only creates more room for the bass but also helps them to come across much more clearly. This may result in the guitars sounding slightly thin when listened to in isolation, but when combined with the bass, both instruments will come across much better while complimenting each other nicely.

Now that we have the tools to depict key elements and processing, let’s take a look at the mix as a whole.

Any musical performance that features more than one melodic or rhythmic element, be it live or recorded, requires these elements to be mixed. Traditionally music was performed live and the mix was achieved by intelligently positioning the individual mix elements and augmenting where necessary. (You want the violins to be louder? Get more violins!)

In the early days of recording, where the performance was captured completely live with one or two microphones, a mix could be achieved by moving the musicians relative to the microphone(s), often during the performance to create dynamic variation.

In live performance we’ve evolved methods whereby each key element is miked or taken direct individually, so that we can treat them individually before combining them together in the mix.

So what happens if we combine our drum kit with the guitars and throw a vocal on top? (Figure 7)


It’s starting to look a little messy now but a mix is a complex interaction of multiple elements, so that’s quite normal. The vocals have been compressed to narrow their dynamic range and help them sit on top of the mix, but there’s still a risk of them being swamped by the other instruments that have energy in the same frequency range (such as guitars). Being as the vast majority of music we mix at gigs is song based, ensuring the vocals can be heard is a key challenge.

So what can we do to make them stand out a bit more? The answer, of course, is reverb, depicted here (Figure 8) using an outer glow. They key is to use a reverb that’s small enough to ensure the vocals don’t sound too distant while exploiting the spectral smearing and stereo widening that can help to make the vocal sound bigger.


A plate with a reverb time between 1.0 and 1.6 seconds and a pre delay below 10 ms usually does the job. I sometimes find that rolling off the top end (or adjusting the high ratio) of the reverb helps to make it sound more subtle – less like a digital reverb and more like a natural acoustic space around the vocal.

But that’s not the only way to make a vocal stand out in a busy mix (Figure 9). Another trick I like to use is to apply a slap-back delay to the vocal, here depicted by the black drop shadow. A slap-back delay can be anything between 50 and 300 ms, but I find a setting of between 100 and 180 ms works particularly well on vocals in mid-tempo songs.

The feedback gain should be set so there is only one audible repeat – typically achieved by setting it to 10 percent. This creates a single echo very close to the vocal which has the effect of doubling it and helping it stand out against the background noise. Again rolling off the top end of the effect can help make it less obvious and more subtle.

As mix engineers we’re always striving to build better mixes, so hopefully these pictures have been worth a few thousand words and have provided a unique insight into the process.

We might think we mix with our ears, but our brains are doing all of the hard work, so anything that can help us visualize such abstract concepts will enable us to better understand the nature of the mix and produce consistently high-quality results.

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