– Or: All things being equal, the equalizer can be surprisingly unequal

Yeah I couldn’t resist the play on words.  I just couldn’t.  May as well try to get me to stop double-spacing after periods or using the Oxford Comma.  It’s built into my genetic code and you, my dear and cherished reader, are stuck with all its (in)glory.

Welcome to my first deep dive into a concept – which is also a piece of equipment – in Audio Engineering!  This week we are going nose (ear?) first into the idea of a concept called Equalization.

If this is your first visit to this blog and you need/want/fear a refresher on the fundamental preamble regarding sound waves and frequencies, smush your smushable mouse button / the left side below your track pad over THESE WORDS for hand-drawn examples and explanations.

This post is going to dive into some very specific aspects of the equalizer! What one looks like, and some actual watchable examples of my favorite one in action (The Fabfilter Pro Q 3 is hands down my favorite software equalizer.  I am not sponsored by them in any way; I just love the thing), and some explanations of all of the above.

As a super nerdy aside, I’ve been wanting to be lazy and refer to Audio Engineering as AE for short.  Which got me thinking it would be cute and hipster to refer to it as Æ.  I’m guessing just using that ancient letter is probably going to destroy my SEO ratings so maybe I’ll do it just that once and then you can be in on the joke.  If I ever get lazy and say AE, you will know what it should really look like.

Moving on!

What is the difference between equalization and and equalizer

The idea of equalization is the process of manipulating the way something sounds by adding or decreasing the amplitude of certain frequency ranges: making them louder or softer. Contouring your waveform like an expert stylist gets all up in coiffure theory.

The equalizer itself is a tool that can be used to accomplish what is outlined above.  This tool makes those manipulations possible.  The scissors and clippers for the stylist.  Just like the stylist, there are subtle things that can be done to hair to refine, and there is also the mow-hawk.  That approach can exist in equalization as well.  Later on I’ll show a manipulation that actually looks like a mow-hawk that you would probably never ever ever use on purpose but it’s artistically (and sonically) funny.


Gotta go back to “Ma Bell” for this one.  Once upon an ancient time when “land lines” were the only method of voice communication outside of actually seeing somebody face to face (oh the long distance bills I rang up as a kid not knowing any better…) telephones were able to connect to each other via means of junctioned copper wire.  No big deal, right?  Pick up your phone, dial a phone number – or ring the operator and ask to be connected to words that to this day don’t make sense to me (another blog post!) – it rings and somebody picks up the other end and VIOLA!  The literal phone conversation has begun.

Sometimes those distances were extremely long.  A call from Los Angeles to New York had to take physical distance into account and, as a result of the distance, there could be frequency degradation.  Usually in the high-frequency arena.

The solution?  A device was built to compensate for that loss to make them sound “equal” to the expected “quality” of the short distance call to your neighbor’s house asking if they have any milk because we can’t just go there and ask.

You know who you are.


Referred to above! The device that made the long distance call audio quality equal to the short distance call.  Ba da bing, ba da boom.  These devices were highly specialized at the time and excruciatingly expensive.  They got the job done though!

As time went by, equalizers started getting used in more settings outside of the phone industry.  Public address systems use them to compensate for rooms that sound wonky.  Audio engineers use them to compensate for recordings that sound wonky.

I vote for renaming it to “The De-Wonkifier.” WHO’S WITH ME??

Now that we got that nonsense out of the way

Examples!  Here we go.  The following are not even remotely comprehensive.  Like, not even.  They are the start of some examples.  These will probably continue into another post with still yet more detail.  For now, this is what I’ve got.  Enjoy!

Equalizer Example 01 – Quick rundown

In all of the examples for today, I am using what is called a “parametric” equalizer.  It’s kind of my bread and butter go-to because it allows me to pinpoint and tweak specific “parameters” of the sound.  The view of this specific one starts waaaaay down low at around 10hz – a frequency you can’t hear but it probably feels great in a massage chair – all the way up to twenty thousand hertz – twenty kilohertz, or 20khz – and everything in between.

Other types of equalizer exist.  No foolin’!  Out there in the wild.  That’ll be part of episode 2 of this mayhem.

On to the video example!

The example above uses my voice as the demonstration and outlines some specifics of what frequency ranges respond where and how based on just my voice.  Most of those things can apply to just about anything that is a recorded sound and could potentially need modification.

Quick note: I just this moment realized that I left my task bar visible when screen capturing.  That could have been embarrassing!  Not that I ever have things open that would be such.

Pretty sure I wouldn’t, at least.

I was hacked.

Prove it.

Where was I? Oh yeah.  Examples based on my voice and how they apply everywhere else. The “mud” range is pretty universal, sibilance, air and presence, they’re all useful things to know when de-wonkifying your audio.


A side note about Filters

I was going to make a joke about how the only thing you need filtered is the coffee that someone SHOULD BE preparing and bringing to your bedside.  But it’s not funny if that’s not happening so I won’t.

It took me a couple decades to finally look up the difference between an “equalizer” and a “filter.”  A filter is used to cut undesirable frequencies out.  Filter them out.  Like how coffee grounds are filtered out of your bean-tainted water.  Or how all the veggies are dumped into a strainer after a nice long short-rib braising and filtered out, leaving only the glorious liquid.  If you used enough stock.  Which I didn’t.  That’s another story for another time.

Filters cut things out.

Equalizers, on the other hand, can both cut and boost frequencies to get the desired response.

I can’t remember but I believe there may be a few examples where I used the word filter in the context of boosting something.  That is a faux pas.  I’m also too lazy to go back and recreate the video.  Because reasons.

Anyway.  That’s the difference between the two.  Filters cut things out, equalizers can cut and boost.  Which means filters only de-wonkify while equalizers can be made to wonkify.  Rewonkify.  Extra-wonkify.  It’s getting confusing in here.

Equalizer Example 02 – What does the whole frequency response of my voice look like?

This is a fun experiment to take a look at the response of my voice through the microphone I’m using and the room that I’m in.  Neither of those things are The Best by any stretch but they’re getting the job done.  You’ll see some trends in terms of where the roots of my voice are starting and how obnoxious sibilance really is.

Also, I know I said it in the video, but purple.  You can’t go wrong with that.

I want to believe that there’s something educational about that one outside of looking cool.  Write me back and let me know if that one was worth your time!  Or not.  Feedback is the best.  Except when it’s at a live show because someone didn’t cut out the ringing frequencies in the sound system and it gets loud and awkward and people cover their ears and you have to look for a new job…

Equalizer Example 03 – The High Pass Filter

So there we were minding our own business.  When all of a sudden, you learned all about the high pass filter!

As mentioned above, the filter is used to cut or exclude or remove things.  Desirable or not.

As the name sorta kinda implies in a confusing way, the high pass filter will pass only high frequencies directly to you, the listener.  In the example video, I demonstrate what that might sound like when used in the extreme.

There are plenty of cases where this is super useful.  Instruments that have their overall sound in high ranges may not need any low frequency energy at all in order to sound awesome.  The solution?  Use a high pass filter.  Cut all those things you don’t need out and save room for stuff that might want to live down in the basement. The drum kit crash cymbal doesn’t need much low end stuff. Get rid of it!  That hub cap being hammered in the latest industrial track?  Nope!  Filter all that stuff out.

In the thumbnail above, you can see it in action.  It has a nice slope going down the left where anything prior to it is filtered out.  Left behind.  Thrown out on the lawn after the locks are changed.

Where there is a high, there has to be a low, right?  Good guess!  Let’s move on.

Equalizer Example 04 – The Low Pass Filter

Where there’s a will, there’s a way.  What goes up must come down.  If there’s a high pass filter, there’s a low pass filter.

None of those things are related but whatever.

The low pass filter works in effectively the same way.  The low pass filter passes those low frequencies on to you, once again, the listener, and leaves everything else out.

It’s possible that you’re not going to be able to hear some of the example in this video through a mobile device or a laptop speaker.  My apologies in advance, it won’t linger there too long.

So therein is an example of the low pass filter where only low frequencies are left intact.  Cool stuff!

And now onto the final of today’s examples:

Equalizer Example 05 – The SHELF

No contractors required.  Don’t have to drill any holes.  None of them weird butterfly drywall screw sockets that you should use instead of some of the cheaper plastic ones no matter what weight rating they say they have.

The shelf equalizer shape looks just like that: a shelf.  A curve up from where you’re at to a flat line at the destination in either the Treble or Bass ranges.  A shelf.

Please note.  This is the video where I referred to it as a “shelf filter.” This is wildly incorrect.  Please forgive my ignorance.  I’ve been tweaking mixer knobs and mixing audio things for going on 27ish years now and I’m -still- learning new things.  Sometimes self-taught is awesome.  Other times – like this – it’s not.

So when you watch the video above, you’ll see an example of what those shelves will do to boost and cut broad ranges of bass and treble.  They’re pretty straightforward.  I personally don’t find them quite as useful in most of my mixing where audio is concerned but sometimes it’s fun to run music through one and enjoy the modified clarity.

I’m more of a fan of either more surgical cutting and boosting (which we’re going to get into in the next entry) or just using Pass Filters to keep only what I want and return-to-sender that which I do not need.  Quick and dirty.  Or clean.  Depending on what you’re listening to.

In conclusion for now

In the next entry, we’re going to get into a few more concepts that will be fun to explore.  I won’t explain these quite yet but more as a list to remind me of what I think I want to go over next time:

  • Band pass filters (you can’t use these to get back stage)
  • Band reject filters (no you can’t use these to filter out when the record label sends you a note saying your album isn’t quite their speed)
  • Bell / Notch shapes (not taco.  unfortunately)
  • Gain (boost/cut) and Quality Factor (Q) and how they impact what you’re doing (John de Lancie may have had a hand in this)
  • Ramblings on how badly equalizers are abused and how to tone it down (ha ha ha)
  • Example of how to “fix” something that isn’t sounding quite right (this will be fun)

That’s it for today!  It’s a mouthful.  Eyeful.  Earful?  I don’t even know anymore.  Thanks for hanging with me this far. I hope you’re enjoying my unique and borderline twisted take on this thing that we use so much in the world of audio manipulation.

Until next week!

-= george =-



Are we having fun yet?

About the Author

Straddling the line between the arts - voiceover, music composition, session performer, album mixing - and the world of durable medical equipment. Probably should have spent more time playing on the balance beam as a kid instead of obsessing over Commodore 64 games.

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