Midrange Bias

Everyone talks about bottom-end punch, top-end clarity and sometimes even the stereo width of an audio production, but very few people focus on the one thing that never goes away no matter where your mixes get played – the midrange. Get that right and you’re well on the way to achieving a well-balanced sound that translates across the widest array of systems.

I know we’re all a bit stir-crazy at present, and the lockdown we’ve all endured here in Australia remains the focus of everyone’s attention, but to hell with it. I’m not dwelling on that today. Today we’re talking audio, and more specifically midrange. Oh the joy…

Finessing the midrange of a mix is one of the most crucial aspects of achieving a decent sonic outcome for your music, particularly one that translates out in the world. I know we don’t go out much at the moment, but the music we produce still does. So it’s vitally important to remember that it’s not enough to have your mix sound epic in your own space; it has to sound good everywhere.

We all know this of course, but sometimes it’s hard to face this reality. It’s particularly demoralising when that epic mix of your newest bass heavy, uber-doof-ified folk song (that you’re convinced breaks new ground) sounds like crap when you flip the mix over to your NS10s or Auratone replacement speaker.

Suddenly all your hard work vanishes into a low-end vortex, revealing a decidedly unbalanced, harsh, midrange-heavy version of the mix that’s nothing like what you’ve been hearing through your big monitors. It’s enough to make you never want to reference your music through small speakers again! But that’s the biggest danger – shying away from things that show your work in the harshest light is a slippery slope to Nowheresville.

Really great mixes are only ever achieved when you regularly face the music – as it were – by playing your work through small, shitty speakers at tediously low levels. That’s where the hard work gets done. It’s not fun or glamorous, and it’s often frustrating to be confronted by just how far away your mix remains from greatness. But with a bit more effort and a serve of humble pie, mixes eventually punch through this barrier and come out the other side better off.

Middle Class

What most speakers outside your studio space have in common is their capacity to replay midrange information. Each speaker does it differently of course, but they all do it.

To the great frustration of us audio folks, far fewer of the world’s speakers produce 50Hz and below, or 12kHz and up with anything like the capacity of your control room’s sophisticated 2.1 in-house system. And by the number of eye-rolls I’m anticipating by that statement, I suspect not many of us sophisticated audio guys have a system like that either!

So why the obsession with top and bottom end when most of the time that audio information diminishes to varying degrees once it leaves the confines of your workspace? Well, presumably because it sounds good, but also because not all systems lack bottom or top end (especially if we include headphones in this discussion).

Really great mixes are only ever achieved when you regularly face the music – as it were – by playing your work through small, shitty speakers at tediously low levels. That’s where the hard work gets done.

The important thing to realise is that great mixes cater to both. They sound fantastic on big kick-ass systems and tiny boom boxes alike. But we all know this already, right? A mix needs to sound great whether it’s played in another engineer’s million-dollar control room, or your Uncle Joe’s garage on his new Aldi clock radio. That’s what midrange balance is all about.

But What Is It?

I probably need to define midrange before I go any further. Problem is, there is no defining it really. It’s a subjective concept.

Like most things in audio, the definition of midrange varies significantly depending on to whom you speak. Speaker designers, for instance, argue the toss about it for hours, one defining it based on crossovers, the other by distortion specs etc… it’s a minefield.

Mix engineers are in similar disagreement. Good song arrangers will argue (quite rightly) that balancing the midrange is all about instrumentation rather than how things are specifically EQ’d, but it doesn’t really matter how you frame it or where you draw the line.

Suffice it to say midrange is the band on the audio spectrum where human hearing is the most sensitive. It starts in the vicinity of where a tone first loses its bottom end ‘weight’, and ends when you start to define that tone as being about a sound’s upper register.

If that all sounds far too vague to you, you’d be right, and I would agree! To me personally, the term ‘midrange’ conjures up a fairly narrow bandwidth in my head, particularly when I’m mixing, mainly because the three-adjective concept of ‘bass,’ ‘midrange’ and ‘treble’ used to define the 20Hz to 20kHz audio spectrum is far too simplistic a semantic scale in my opinion.

For astute audio engineers, in particular, I would argue that there are at least seven easily defined regions, these being: sub-bass, bass, low-midrange, midrange, upper-midrange, high-frequency and super high-frequency.

My narrower definition of ‘midrange’ occupies a region somewhere between say 800Hz and 2kHz. The others are (loosely speaking, and without adhering to tonal octaves): 20 – 50Hz (sub-bass); 50 – 250Hz (bass); 250Hz to 800Hz (low-midrange); 800Hz to 2kHz (midrange) 2-7kHz (upper-midrange); 7-14kHz (high-frequency) and 14 – 20kHz (super high frequency).

But for the purpose of this article, and to get us back on track here, I would say that most people define midrange far more broadly as existing somewhere between about 400Hz and 4kHz. Some would argue it’s a little lower, others a little wider, some narrower… hence the problem.

Midrange is Wide!

For now, let’s use the broader, roughly four-octave definition of the term, shall we? This wide area of human hearing has many tonal aspects to it, ranging from ‘dark’ and ‘mysterious’ at one end of the frequency spectrum, to ‘clear’ and ‘revealing’ at the other.

Of course, depending on the fundamental frequency response of whatever the sound under scrutiny happens to be at the time, these exact same frequencies might otherwise be described as being ‘woolly’ and ‘masking’ of a sound, or adding ‘harshness’ and ‘bite’ – different terms altogether.

It’s therefore not so much about what frequencies you choose that defines a sound, but what these choices reveal in a sound. If an instrument is already harsh to the ear, adding 3.8kHz obviously isn’t going to make it clearer, it’s going to make it tear your head off! Conversely, 3.8kHz might give a sound that’s perceptively dull and indistinct a new clarity in a mix that’s perfect for that circumstance. It’s horses for courses – obviously.

The Cure

Diagnosing what each instrument requires to sound good whilst simultaneously balance the ensemble of instruments is the real trick. After that, it’s making sure that not every element in the mix gets the same treatment.

Simply adding 3.8kHz to everything is going to make things get mighty harsh mighty quickly, especially if you’re masking this harshness with huge bass through your huge monitors. Take that bottom end away – as so many small systems inevitably will – and the harshness will be immediately exposed.

It’s this overemphasis of a narrow frequency band that’s the real killer. Likewise, cutting too much low-end out of an instrument with high-pass filters can quickly undermine its tone, and for two interconnected reasons.

Firstly, most instruments have some element of low-end in their sound, which, if taken away, quickly renders them thin and weak. High-pass filters are great tools, but used too severely they can quickly make mixes sound small and harsh. And of course, if that happens to your mix, when played through smaller systems it will only grow thinner again, whereupon you’ll regret having put those filters on at all!

Balancing the midrange so that your mix still holds together when it’s played through small, cheap speakers (where frequencies below 350Hz and above 4kHz disappear over a cliff), is thus all about spreading the focus of each instrument’s tonal balance wider across the full breadth of the spectrum, whilst making doubly sure you don’t take too much information out of each instrument’s bass and low-midrange.

That’s why mixing exclusively on big speakers can cause translation problems when you switch to small ones – it’s easy to filter out some of the lows from a sound on big monitors without it appearing to do too much damage… until you listen on small speakers and wonder where all your tone went!

Likewise, avoiding the trap of adding too much bass and treble to instruments like bass guitars and kick drums at one end, tambourines, cymbals and guitars at the other, helps prevent these sounds from changing radically in level (or disappearing altogether in some cases) when replayed at low volume through Uncle Joe’s clock radio.

Not only will these sounds retain their voice through a midrange-only system if their sound includes some portion of low midrange, they will help prevent the mix from losing its fundamental balance. If, for example, you get seduced by a new sub kick sample and forget to add some element of midrange to the sound, on Joe’s clock radio there will be no bass drum at all!

What will that do to the instrumentation of the rhythm section? Nothing good I suspect.

Mixes inevitably sound different through different systems – none of us can stop that from happening. But as engineers we can certainly learn to minimise the impact different systems have on the music we produce.

Remember, midrange information is far more easily replayed by even the worst audio systems than the extreme edges of the spectrum. However, filter out too much low end or extreme tops from instruments during the mix, thinking them extraneous to the sound, and the problems might get worse!

Andy Stewart owns and operates The Mill on Victoria’s Bass Coast. He’s a highly credentialed producer/engineer who’s seen it all in studios for over three decades. He’s happy to respond to any pleas for recording or mixing help… contact him at: andy@themill.net.au

CX Magazine – June 2020   

LIGHTING  |  AUDIO  |  VIDEO  |  STAGING  |  INTEGRATION

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