Audio Recording

I received an important question from a reader:

“I have been using your idea’s for EQing and it seems to be working in a live setting. I was wondering what your idea’s are for mixing background vocals even to the point of the different parts, Alto, Tenor, etc. Any idea’s here would be appreciated. Thanks, Garth.”

Hi Garth,
You indeed ask a very important question about vocals EQ particularly its application in choir and background vocals live performance. OK here is a great idea on how to mix this situation.

First, you need to know the frequency range occupied by these voice types:

a.) Soprano
b.) Tenor
c.) Alto
d.) Bass
e.) Baritone

The following are the voice range chart in terms of musical notes and frequency:

Source/Credits: www.rochars.org/recorder_frequency_ranges_big

Based on the above chart, the following are the estimated frequency ranges (inside the red box on the screenshot provided above):

a.) Soprano (female) =500Hz to 4000Hz
b.) Alto (female) = 300Hz to 2100Hz
c.) Tenor (male) = 250Hz to 2000Hz
d.) Baritone (male) = it is not indicated clearly in the chart but a baritone voice is between the bass and the tenor. However based on the chart above, there are three types of bass below tenor. These are: bass, great bass and contrabass. The baritone would ideally fit above “great bass” so the range will be: 175Hz to 1000Hz.
e.) Bass (male) = this has the lowest frequency. The range would be 87Hz to 500Hz.

It would be doubtful if anyone can still sing at 87Hz except for talented bass singers. However the voice frequency range is around 20Hz to 20,000Hz and based on the data above, only 87Hz to 4000Hz are effectively used by the choir voices.

That would also support why the telephone bandwidth is between 300Hz to 3000Hz, but obviously you cannot hear bass voices in a telephone. That range is where the ear is very sensitive to human voices.

So how would you mix this in live setting? In EQ, combination of cutting and boosting is more preferable than relying on boosting alone. So the following settings are suggested (as a start but you can further tweak it for best results in live setting):

Mixing/EQ for soprano voices:

Boost at 2.25 KHz +3dB, Q=2.0
Apply low shelf filter with shelf frequency at 400Hz, -6dB (this will drastically reduce frequencies below 400Hz which is not needed for soprano voices)

Mixing/EQ for Alto voices:

Boost at 500Hz +3dB Q=2.0
Apply low shelf filter with shelf frequency at 250Hz, -6dB
Apply high shelf filter with shelf frequency at 2.1 KHz, -6dB (this will reduce “masking effect” with soprano voices, for frequencies above 2.1 KHz)

Mixing/EQ for Tenor voices:

Boost at 1 KHz +3dB Q=2.0
Apply low shelf filter with shelf frequency at 200Hz, -6dB
Apply high shelf filter with shelf frequency at 2 KHz, -6dB

Mixing/EQ for Baritone voices:

Boost at 400Hz +3dB Q=1.4
Apply low shelf filter with shelf frequency at 175Hz, -6dB
Apply high shelf filter with shelf frequency at 1 KHz, -6dB

Mixing/EQ for Bass voices:

Boost at 150Hz +3dB Q=1.0
Apply high shelf filter with shelf frequency at 500Hz, -6dB