When mixing female vocals the main thing you need to keep in mind is how the pitch has shifted upward, and what this means for important frequencies. For example, the ranges for vocal clarity and sibilance have likely shifted higher, meaning you’ll need to equalize the vocal differently.
Typically speaking, female vocals have different formants our clusters of frequencies, that are typically higher in pitch due to a smaller vocal tract. If you’re used to mixing male vocals, you may need to re-access which frequencies you boost or attenuate since these will likely be different.
We can simulate the effect of formants on the overall timbre of the voice - even if the pitch isn’t shifting, altering the timbre will make the voice sound higher in pitch. Let’s take a listen to this using a formant plugin.
Female vocals will usually have a higher fundamental frequency - meaning we’ll need to consider how we affect the low-frequency range. A female vocal may have a fundamental higher than 350Hz, meaning we can use a higher high pass filter to cut out rumble, without worrying about affecting this note.
With that in mind, let’s introduce a high-pass filter with a high slope, and notice how high we can increase it without cutting into the actual performance.
Similar to our last point, if the full range is shifted upward, this will affect other aspects of the vocal, like sibilance. Whereas sibilance is usually located between 5kHz and 8kHz for most male vocal recordings, they’ll be around 8 to 12kHz for female vocals.
This isn’t always the case of course, but 10kHz is a good place to start when de-essing a female vocal.
Due to the higher fundamental, female vocals may sound a little thinner than usually - if that’s the case we can use a sub-harmonic generator to create frequencies below the fundamental. I’ll use LoAir to create a subharmonic frequency, and subtly blend this in with the original vocal.
If this is too loud it’ll sound really artificial, however, subtle settings work well.
This is a bit of a weird trick, but if you’re finding that your highs are too intense and you’re having trouble controlling them even with de-essing, try diffusing them with a reverb plugin. To do this I’ll use the Pro-R and isolate the reverb to the highs.
I’ll use a room emulation and set the mix super low - this will cause reflections to my highs which diffuse the sound.
If you’re mixing vocals, odds are you’ll use saturation to make the vocals sound full. Since female vocals are often higher in pitch, distorting them will cause higher frequency harmonics to form, which increases the likelihood of unwanted aliasing distortion, since a harmonic could go above the maximum support frequency.
To avoid this all you need to do is turn on oversampling.
Earlier we talked about how higher pitch vocals shift everything upward, and this is definitely the case with important frequency ranges. For example, if I want to increase vowel intelligibility, instead of boosting 500Hz, I may boost 6 or 700Hz - or for clarity, I may boost 3.5kHz instead of 2.5kHz.
Every vocal is different so just use your ears, but keep in mind that important ranges will likely have shifted higher.
It's difficult to say exactly why this is, but I find that female vocals sound better with a flatter frequency response. That said, lots of microphones will hype the highs and lows, so if you’re finding this is the case, lower these ranges first and see if it improves the sound.
An intelligent EQ is a good first step since it’ll flatten it dynamically, but a regular EQ will work well too.