In this video, let’s cover both technical and practical aspects of Mixing Low End
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So let’s start by covering
Why is the Low End so Difficult to Mix?
Instead of wasting time on what the low end is - it’s roughly 20Hz to
250Hz - or pontificating needlessly as to why it’s an important range - you
already know that - let’s just answer what makes it difficult to get right.
The short answer, there’s too much signal competing for limited space.
Let me show you what I mean - if we look at an EQ with a note scale at the bottom,
we’ll notice something interesting.
The distance between octaves is so much more condensed in the lows, than in the highs.
So let’s create a filter at E1 - then, let’s create a filter at E2. E1 is about 41Hz. E2
is about 82Hz. Already, we can tell that 40Hz isn’t a huge range between octaves,
but let’s look at the range between higher notes.
E6 is about 1318Hz, and E7 is 2637Hz. So whereas the distance between E1 and
E2 is 40Hz, it’s more than 1300Hz. between E6 and E7.
So imagine now that you have a kick drum - it’s fundamental frequency is E1 or 41Hz - then,
you have a bass guitar, and it plays E2 or 82Hz. Already we have 2,
very powerful signals that are incredible close in frequency.
But what’s funny is that it can get even worse.
Say the kick’s fundamental is C2 at 65Hz. while the bass is playing a D2 note at 73Hz.
In this instance, only 8Hz separates these 2 incredibly important and powerful instruments.
So if you’ve been feeling like the low end of your mix is driving you insane - it’s not you,
it’s just how sound works. But now that we know what’s causing the issue,
let’s talk about how to fix it. First by considering
How to Produce the Low End
Getting a good sounding low frequency range starts with producing a track
thoughtfully. For example, if the kick and bass occupy the same frequency,
no matter how you mix it, they’re never going to sound distinct.
It’s on the producer to say, “well, if the song’s key is G Major, and the bass’s progression is G1,
C1, then D1 - it’s probably not a good idea to tune the kick’s fundamental to G1.”
Why? Because every time the bass hit’s that G1 note,
the 2 occupy the same frequency, making it difficult to differentiate the 2.
So what would be a solution to this problem? There are 2 options - change
the kick’s fundamental or change the bass’s note.
Maybe the bass plays G2, C1, then D1. Maybe the kick gets tuned to
B1 - since this keeps it in key, but doesn’t overlap with the bass.
All this to say, these things need to get considered during pre-production, tracking,
or the early stages of producing - otherwise, you won’t end up with a mix that sounds balanced.
To illustrate this idea - let’s listen to a kick tuned to G1 while the bass note is G1 - then we’ll
listen to it with the bass playing G2 instead, and notice how the region sounds a lot less cluttered.
3. Harmonics and the Low End
At this point you might be thinking we solved the
problem - all we need to do is ensure that the kick and bass don’t overlap.
But, there are a lot more complexities to consider - mainly with harmonics.
An instrument isn’t just one frequency - it includes a complex array of harmonics
or overtones, and disharmonious frequencies.
For example, a bass may be playing an E1 note, but harmonics for E2, E3,
E4 and more might form depending on the bass, synth, amplification used, and other variables.
Some of these things we can’t control - for example,
I can’t make a bass guitar have less overtones,
nor would I really want to. What we can control though is how we process these instruments.
So let’s say the kick is tuned to G1, just like in our last chapter. Again,
our bass is playing a G2 note. But now, let’s say I add a saturator to the kick drum - this
saturator emulates warm tube settings and introduces a strong 2nd order harmonic.
Well - what’s the second order harmonic of G1? G2. In other words, I’ve saturated
the kick to make it sound fuller, but now it’s interfering with the bass.
Similar situations can occur with reverb, compression, other forms of distortion, and so on.
For example, if I reverberate the kick, the low frequencies above the
fundamental will likely be part of the decay, causing overlap with the bass.
So, we’ll need to be careful with what processing we add to our low frequencies.
The best way to find what helps your low end is to use your ears - otherwise, you’ll need to
memorize what processor adds what harmonics, while keeping track of which notes are being played.
With that in mind, let’s listen to the same G1, G2 example as before,
but this time I’ll add saturation to the kick that first has a bad reaction with the bass,
and then saturation that works around the bass’s frequencies.
4.
Improving Lows with EQ
Now that we know how producing affects the lows,
and what to avoid during mixing, let’s talk about what we can do to reduce some issues.
EQ is probably the most powerful tool in mixing and mastering - In
my opinion, it’s also the best at improving a problematic low end.
Let’s put 1 EQ on our Kick and 1 EQ on our bass - when we do,
we can observe where they overlap, and what makes them different.
So, let’s say one of the kick’s harmonics is overlapping with the
Bass’s fundamental. With the EQ on the kick, we could attenuate that frequency
with a bell filter. This way, the bass’s fundamental has more room.
Or maybe, both the kick and bass have harmonics on or near the same
note - making that part of the lows too aggressive. We could attenuate
the problematic range on either the kick or the bass, or both to varying degrees.
Now, notice that any changes I make with EQ are static - in other words,
once the filter is introduced, it kind of just stays there. So,
if I attenuated frequencies on the bass, those we’ll be attenuated at all times.
This isn’t a bad thing, but if we’re trying to separate the kick and bass, or make the
low end more balanced, it would help if this filter only existed when the kick was present.
With a Dynamic EQ, we can do just that. With the EQ that’s inserted on the bass,
let’s side-chain the kick drum. Then, we’ll change the band that
we used to attenuate frequencies from a regular band, to a dynamic band.
Lastly, we’ll use the side-chained signal as the trigger for this band,
meaning whenever the kick is present, this filter will measure the kick’s signal,
and attenuate the frequency range as a result.
Now, it’s possible that the static band will sound better, or that the dynamic band will sound
better. The point is, you have the option and should try them out to see which you like more.
So, let’s listen to our kick and bass example, starting with the EQ disabled. Then,
I’ll enable a static filter so we can hear that. Lastly, we’ll listen to the EQ with a dynamic band
that’s triggered by the kick’s signal. Let me know in the comments which one sounded the best to you.
5.
Improving Lows with Compression
If you’ve been mixing for a bit, you’ve definitely heard of bass-ducking. This is when we compress
the bass, using the kick as the trigger. When used aggressively, it creates a pumping
sound, which can be used creatively - but when done subtly, it can create room in the low end.
So really quick, let’s insert a compressor on the bass and use the kick as our eternal side-chain.
Depending on the compressor, you may need to
select the external side-chain as the trigger or key for the compression.
Once you do, try to attenuate the bass by about 1-3dB whenever the kick hits. Be sure
that any automatic make up gain settings are turned off, and if it’s available,
use a little bit of lookahead to help the compressor read the kick’s signal more accurately.
This will ensure that compression to the bass occurs right when the kick
hits instead of a short amount of time after the kick hits.
So let’s listen to it, and notice that although it’s subtle, it is helping. Then, let’s combine
it with the EQ static attenuation we used last chapter and notice how they complement each other.
6.
Using Exciters on Kick and Bass
Another option we have is to augment the kick and bass in areas where they don’t overlap.
We’ll notice that although the kick and bass have similar frequency ranges in the lows,
in the highs, there’s a lot more variation.
If we amplify these higher ranges, we can create unique identities for the 2 instruments,
helping listeners discern what’s the kick and what’s the bass.
So let’s use this free plugin Fresh Air - inserted on the kick and on the bass. Then
we’ll boost both of the filters and adjust them until we can hear them as separate instruments.
What I like about this plugin is that it amplifies the highs with EQ filters, as well as introduces
high-frequency harmonics - the combination really clarifies and brightens the sound.
If we combine this insert with some of the other forms of processing we’ve been using,
we’ll notice how things are really starting to clear up and create room.
So, let’s take a listen, first with this plugin disabled, then enabled,
and then we’ll enable our EQs and side-chained compressor from the past 2 chapters.
7.
Clearing Mid-Range Instrument Overlap
So far we’ve been focusing on the kick and bass - but other instruments can,
and often do, contribute to a clustered low-frequency range.
Although we typically think of instruments like guitars, vocals, strings, and certain
synths as occupying the mid frequencies, they often stretch all the way down to the lows.
For example, a guitar in standard tuning can go as low as E2, or 82Hz.
A piano can go as low as A0, or 27.5Hz. Whereas a bass vocalist
can typically sing as low as D2, or about 73Hz.
All this to say, if you have additional instrumentation that occupies the low end,
but doesn’t need to, attenuating their frequencies from the range
can be a really effective way to clean up the lows.
For example, say I have some BGVs that occupy the lows - I could use
a high-pass filter to attenuate up until one of the overtones.
The same could be said about guitars, synths, or strings.
Since our brains will fill in the gaps, we can attenuate an instrument’s fundamental, and we’ll
still perceive it as being the same note. So if you’re mixing, maybe you’ve done some of the steps
we’ve covered already, but you’re still having issues, check to see what is included in the lows.
You’ll likely find a lot of instruments that don’t need to be there.
Let’s take a listen to high-pass filters being applied to instruments that occupy the low end
and notice how the mix sounds cleaner and more balanced with these signals attenuated.
8. 2
Very Important Frequency Ranges
So far, we’ve mainly been looking at the low-frequency range - which makes
sense since this video is about mixing low-end.
But one important thing to keep in mind is that equalization and processing that
changes the frequency response shouldn’t be thought of as I dip this, or I boost that.
Instead, it should be thought of as a ratio.
For example, if I attenuate the lows,
I’ve altered the ratio of my low frequencies to my mids and highs.
Or if I’ve amplified the highs, I’ve altered the ratio of my highs to my mids and lows.
When we think about it this way, we realize that amplifying the highs is a
lot more similar to attenuating the lows than we might think. In both scenarios,
we’re adjusting the ratio of lows to highs in a very similar way.
So let’s look at this in a little more depth - in particular,
I want to talk about 2 incredibly important frequency ranges.
The area around 250Hz. and the area around 3.5kHz.
The area around 250Hz is where we have a lot of info - we have fundamentals
and overtones for guitars, vocals, and more, as well as overtones for our bass and kick.
The area around 3.5kHz is what our ears have evolved to be most sensitive to - the
shape of our ears and size of the ear canal all augment this range for the
sake of prioritizing speech. This is why if I boost this range on a vocal or an instrument,
it sounds a lot clearer and more present.
What’s even more interesting is that 250Hz is the most prominent masker of 3.5kHz - in other words,
250Hz very easily and often covers up and masks 3.5kHz and the frequencies around it.
Many times when our lows are sounding out of balance, what we’re hearing is
a very busy 250Hz range masking a really important 3.5kHz range.
So as I was saying before, we need to improve the
ratio. Either we can amplify 3.5kHz or attenuate 250Hz. Or, we could do both.
So let’s take a listen to both of these filters being applied to our kick and bass,
as well as some instruments that occupy the lows to highs mids,
and notice how effective it is at cleaning up the mix.
9. Super Smooth Pultec Bass Settings
Before we wrap this video up, I wanted to leave you with a fun and easy-to-replicate
technique. It’s a variation of what’s sometimes referred to as the Pultec Trick.
If you copy these settings into a Pultec EQ or emulation,
you’ll create a really smooth, but detailed sound.
I’m using this soft tube Pultec emulation,
but Analog Obsession makes a fantastic free alternative called RareSE.
So here are the settings.
Set the low-frequency range to 20Hz. Then, boost by 5 and attenuate by 3.5.
Next, increase the bandwidth of the high-frequency filter to 10 or completely broad.
Next, set the high-frequency value to 5 or 5kHz. Boost it by 5.
And that’s it! If we take a look at how these settings affect the frequency response,
we’ll notice our lows are amplified by about 4dB,
but 250Hz and the range around it is attenuated by about 1.5 to 2dB.
These settings will make the bass or kick more impactful
without contributing to masking and loss of clarity.
Then the filter smoothly increases until the ranges around 3.5kHz,
where it’s amplified by about 3dB - adding clarity and detail.
In short - these settings accentuate what we want more of, and help to differentiate
the low-end instrument for others, all while avoiding creating a muddy sound.
We’re going to include this preset in our membership page - adding
to our list of custom presets that come with the membership.
Let’s take a listen to these filters being
applied to our bass and notice how they create an impressive sound.
(Demo here)
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