What has become quite current in most electronic music productions is the use of formant or vowel equalization on the sound sources. This can be heard quite a lot in the talking-style basses that are being reproduced in popular productions. I am going to show you how to setup a synth in Logic using a selection of different Channel EQ's with formant/vowel EQ settings. From there I will show you how to automate the volume parameters between these EQ's so that it produces vowel-like sounds to the synth.

Step 1 '" History of Formant EQs

Gunnar Fant defined Formants as '˜the spectral peaks of the sound spectrum of the voice' From Fant's studies came the Vowel formant regions or ranges:

Vowel Main formant region

• u 200'"400 Hz
  
• o 400'"600 Hz
  
• a 800'"1200 Hz
  
• e 400'"600 and 2200'"2600 Hz
  
• i 200'"400 and 3000'"3500 Hz

You can look up more information on Formants at Wikipedia here.

A good example is the classic kids toy, the Texas Instruments Speak & Spell. It used formant synthesis to produce the computerized speech sounds. I am going to use these regions/ranges to build up Channel EQ's that represent each vowel formant. First lets get a synth going.

Step 2 '" The Vowel Formant Synth

I am going to be using the ES2 synth. I have enabled the 3 oscillators, each with a different waveform. I have also detuned the oscillators to create a bigger synth sound.

I have added a slight Chorus effect on the synth and have increased the Sine Level and the Distortion Level. Mix the 3 oscillators together in the triangle mix window to get the favored sound.

I have setup 5 busses on the Synth channel strip. These will represent the 5 vowels (A, E, I, O, U). Make sure each bus level is at its maximum. This can be done by Option-clicking each Bus level. I have renamed the auxiliary bus channels according to the vowel letters.

Step 3 '" The Vowel Channel EQs

I have inserted a Channel EQ on each auxiliary channel. 

This is the A Channel EQ

This is the E Channel EQ

This is the I Channel EQ

This is the O Channel EQ

This is the U Channel EQ

Take a listen to the vowel sounds below:

A: 

E: 

I: 

O: 

U: 

Step 4 '" Automating the Volume Parameters

Once you have setup all the Vowel Channel EQs on the channel strips, buss these auxiliary channels out to a new auxiliary channel.

I have renamed this new auxiliary channel '˜Vowel Synth' and inserted a Compressor on this channel strip to tame some of the transients as the synth moves through the different Vowel channels. I have applied a 2.7:1 Ratio, a Knee of 0.7 and have pulled the Threshold down to -22dB. You can check what Attack and Release settings suite your sound. I have also enabled the Limiter and have decreased the Limiter Threshold to -0.3dB.

Here is where the fun comes in. Move back to the Arrange Window, and enable the Automation View (View > Track Automation or simply press "A"). I have left the volume for the A aux up, and have lowered the rest to 0. Now draw in some automation for the '˜A' channel. Start by decreasing the volume for channel '˜A'. Whilst this decreases, start increasing the volume of the channel '˜E'. Do the same for the rest of the channels. Your Automation will start to look like this:

You can listen to my formant vowel sounding synth:

Now here is the same synth within the context of a beat:

Conclusion

As you can see, quite interesting results can be had working with formant vowel EQ settings, and by automating volume changes through these vowel sounds.

Try incorporating this technique into your future productions. It can introduce a different element to your synth textures and timbres. You can also look at the new synths that are coming out with formant settings on their interface like Native Instruments' Razor and Massive synths.