Professional Analog Mastering.
Professional Analog Mastering.
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The mids contain the majority of information in a recording.
It helps to know that any instrument includes a fundamental frequency, and harmonics or overtones.
The fundamental is the lowest musically related frequency. Overtones or harmonics are whole number multiples of the fundamental.
So, if we’re mixing a kick, we may think of it as a low-frequency instrument. It’s true that the fundamental and maybe the 2nd order harmonic occupy the lows, but the majority of the overtones are in the mids.
The same could be said for the higher frequency percussive aspects of the kick.
Similarly, a bass guitar may have a low frequency fundamental; however, the overtones, which are a huge part of the bass’s sound, timbre, and tonal characteristics, occupy the mids.
The same could be said for vocals. In this instance, the fundamental may be in the low mids, or fluctuate between the lows and the low mids.
I’ve said it before, but not all instruments occupy the lows, not all instruments occupy the highs - but almost every instrument occupies the mids. For that reason, it’s an incredibly busy area that, when balanced and processed properly, will improve your mix exponentially.
Let’s take a quick listen to a mix with the mids soloed, and notice how every instrument in the arrangement can still be identified.
Watch the video to learn more >
This applies to the lows as well, but since we have so much info in the low mids, it presents more of a problem.
In short, each perceived note, each semitone, so say C to C#. Or C# to D is about a 6% difference in frequency.
If we look at the low mids and start with the note A3, or 220Hz, that means the next semitone above A3 is 6% higher in frequency.
A#3 is about 233Hz. So between these 2 notes, we only have a 13Hz difference or space between them so to speak, which isn’t much at all.
Comparatively, the difference between A7 and A#7 is about 210Hz.
But why is this important, and what does this mean for the low mids?
In short, any modulation to these frequencies, that is, any frequency fluctuation to a note in the low mids can easily shift the pitch enough to create the perception of a semitone above or below the intended note.
This can happen with chorusing, modulated reverb, and delay. But, just as importantly and maybe more surprisingly, it can happen with wave shaping.
So, compression, saturation, clipping, upward processing, and even gating can reshape the wave in a manner that causes the perception of a different note. It does this when it cuts into an oscillation.
Imagine you have a sine wave and attenuate right in the middle of the peak, or middle of the trough. If severe enough it can double the peak and or trough, in turn changing the perceived frequency.
One form of saturation called rectification doubles the frequency by inverting the phase rotation of the negative side or the trough.
In short, processing can make this already busy area a lot more convoluted when modulation is introduced.
All this to say, be careful how aggressively you saturate and or compress the low mids.
Additionally, be mindful of any modulation you might introduce through delay, chorusing, reverb, or other temporal effects.
Let’s take a listen to frequency modulation to the low mids. Notice that even subtle settings can cause the perception of a different note than intended.
Watch the video to learn more >
Formants are clusters of frequencies that contain information about the vowel being sung or spoken.
Typically, there are 3 vocal formants. From lowest to highest in frequency, they’re called F1, F2, and F3.
They vary from singer to singer, and from vowel to vowel; however, all 3 formants occupy the mid-frequency range.
For example, if a vocalist with a 17-centimeter long vocal tract makes the sound oo, you’ll likely observe formants at 400Hz, 1100Hz, and about 2.2kHz.
However, if the vowels are sung, they’re more likely to adhere to frequencies that correspond to the intended note.
The most important formant is F3 or the highest pitch formant.
These occur within the frequency range that we’re most sensitive to - that being between 2kHz and 5kHz.
Since our ear canals resonant within this range, this is often the area we associate with clarity, or the ability to easily perceive what someone is saying or singing.
With that info, it's super easy to identify the range in a vocal, or any instrument, that affects the perception of clarity.
If the vocal or instrument is unclear, then somewhere between 2kHz to 5kHz needs to be boosted. If it sounds harsh or too upfront, then that range needs to be attenuated.
When working with vocals, listen intently to find the most accurate range for the 3rd formant - if you isolate it properly, very little change is needed to greatly affect the sound.
Let’s isolate the range in a vocal and notice how much it affects clarity.
Watch the video to learn more >
Getting saturation right in the mid-frequency range is difficult - it already has a lot going on as we’ve discussed.
For that reason, I notice one of the biggest issues with the mids comes from saturation - an additive form of processing that adds a lot of additional information to the mid-range.
For example, say I want to saturate my kick drum.
Again, the fundamental may be in the lows, but if the fundamental is triggering the saturator, which is likely the case, then we’re generating multiples from it.
This means harmonics will form in the low mids, which may not have been the intention.
Or, maybe I’m saturating the vocal, and again, the fundamental triggers the saturation most often. Then, the majority of the time, harmonics will form above the fundamental. If that fundamental was 220Hz, then harmonics are forming at 440Hz, 880Hz, if we generate even harmonics, or 660Hz and 1100Hz if odd harmonics form.
The same could be said with any form of frequency-specific saturation applied to instrument groups.
Say I want to saturate the low mids, and I’ve isolated 200-500Hz.
In this instance, the generated harmonics will form above this range. If there’s a strong harmonic at 200Hz and it triggers the saturation, then 600Hz, 1000Hz, and other odd-ordered harmonics will form.
This means the range above the saturated band will be amplified.
So, if you want to saturate an instrument, keep in mind what aspect of the performance will trigger the saturator most often.
A multiple or multiples of that general area will be what’s amplified in the process.
If I want to add clarity to my vocal and saturate it, then isolating a band below the 3rd formant is a good idea.
The harmonics will form in the formant range, amplifying it, which creates clarity.
Something similar can happen with other additive forms of processing.
Reverberation in the low mids will amplify the low mids. Delay in the high mids will amplify the high mids, and so on.
All this to say, keep in mind how additive processing will affect the frequency response.
Let’s listen to saturation introduced to a vocal. Notice how the frequency response of the mids changes when I switch between the various saturation bands.