Background vocals can be a catchall term for any number of type of non-lead vocals. These include harmonies, gang style or choir style vocals, or simply backing vocals which sing a unique melody with its own timing against the lead vocal. The key to mixing background vocals is to make sure they have a lot of separation from the lead, either panning or depth wise as well as tonally via EQ, so let’s focus on background vocal EQ itself.
Background Vocal EQ
As I just mentioned, the key to background vocals is to keep them out of the way of the lead. This makes both vocals stand out carves out space particularly for the lead.
As such, I recommend two filter points on background vocal EQ:
High Pass at 300Hz
If you’ve seen my vocal EQ cheat sheet, you know that I recommend high passing ALL vocals, not to mention virtually every track in your mix.
This is because it both cleans up a vocal by filtering out unwanted frequencies like room noise as well as dedicates the lowest frequencies of your mix exclusively to the instruments which need it.
I talk more about the importance of using high pass filtering in my overview of low ending mixing.
With lead vocals I typically recommend high passing around 130Hz on female vocals (or 100Hz on male vocals) with an 18dB/oct slope:
This cleans up their low end without cutting into the body of the voice or noticeably changing the sound of the voice.
With background vocal EQ, I tend to go as high as 300Hz. This does noticeably thin out that vocal but by design so that the vocal body frequencies in that 150-250Hz region are reserved exclusively with the lead.
This is half the battle in helping to get the background vocals out of the way of the lead. And while scooping out the body takes a little of their low end thickness away by way of that high pass filter, it helps to create some contrast and separation between the two types of vocals, particularly when they’re playing at the same time.
Low Pass Filter at 5k-6k
I like to use a low pass filter in my background vocal EQ for ultimately the same reason I like that high pass filter, to help create that contrast.
Unlike the high pass filter, the low pass filter is allowing every frequency to pass through untouched BELOW a certain point:
Similar to how the high pass filter creates a slight thinning effect to leave the body and warmth of the lead vocal all to itself, a low pass filter on the background vocal EQ helps to prioritize the highest frequencies just for the lead vocal.
Specifically, putting a low pass filter with an 18dB/oct slope in that 5-6k pocket shaves down high end on the background vocals so the lead has that sharpness, brightness, and top end edge all to itself without working to the detriment of the background vocals.
Like that low pass filter, it’s a subtle effect on the top end which doesn’t kill the background vocals, it just smooths them out a bit.
Because we perceive high end noises as being closer, the low pass filter also subtly pushes the background vocals farther back in the mix, especially compared to the lead which is still hitting up front which is what we want.
The transients of the vocals which asserts itself on certain syllables like “T” and “S” sounds also exist in that 5k+ range.
The high pass filter dulls their prominence on the background vocals, allowing that lead to cut through the mix better by comparison.
Background EQ Reviewed
These two simple filters, 300Hz and 5-6kHz with 18dB/oct slopes, are the key to background vocal EQ as they help create that contrast with the lead vocal but just as importantly they ensure that the lead vocal doesn’t have to battle for those frequencies.
Whenever you have two instruments which share the same frequencies, you need to be ready to make complimentary cuts on one if not both tracks, and vocals are no exception.
Not only will the lead better assert itself, but the background vocals will sound better next to the lead and in the context of the entire mix with that subtle difference, plus that low end filter again nudges the background vocals a touch farther back in the depth of the mix.
As I mentioned in opening, this is only half of the battle, so remember to check out my guide to panning backing vocals for tips on where to pan the aforementioned backing harmonies, gang or choir vocals, or unique background vocals.
Other adjustments to your background vocal(s) might be necessary, so refer to my overview on vocal EQ in general for tips on dealing with specific issues at frequencies, in this case within that 300-6000Hz range our background vocals are existing in.
