Choir Sounds Without Samples

The Roland VP-330 Vocoder Plus

I have one of these. It's a really great keyboard. In addition to a great vocoder and analog strings, it has male and female choir sounds generated by running regular analog waveforms through formant bandpass filters and chorusing the output. These choir sounds have been used on recordings by many artists including Vangelis, who used them heavily in the soundtracks of Chariots of Fire (beginning of Eric's Theme) and Blade Runner (unicorn dream sequence in Director's Cut).

Below are some patches I created using a similar technique.

I did a lot of research about formant frequencies and tried values from several different charts in books that produced very bad results. Finally I found this chart of formant frequencies posted by Ric Miller in the archives of the Analogue Heaven Mailing List. These values sound great! I have developed patches around both the "Ahhh" and "Eeeee" values for men, women and children. The child values produce great boys choir sounds.

To the formant frequency chart I have added the note values for each frequency calculated with the wonderful converter program on this web site. On many synths the values of the filter cutoff are measured in meaningless units from 0-100 or some other arbitrary range. In these cases it is necessary to tune the filter by ear by playing the note at the desired frequency, cranking the resonance on filter as high as it will go, and moving the filter until it is right on top of the note you are playing. You know this has happened because the sound reaches maximum loudness and probably distorts as well. Then turn down the resonance until you like the sound. This is how I tuned these choir sounds on the JD-800. Also, you must set the filters so they do not follow the keyboard notes AT ALL, or velocity or anything else.

(All values are rounded to the nearest half step.)

Speaker         F3            F2           F1        
------------------------------------------------
IY (beet)
Man        3010 = F#7    2290 = D7     270 = C#4 
Woman      3310 = G#7    2790 = F7     310 = D#4
Child      3730 = A#7    3200 = G7     370 = F#4

IH (bit)
Man        2550 = D#7    1990 = B6     390 = G4
Woman      3070 = G7     2480 = D#7    430 = A4
Child      3600 = A7     2730 = F7     530 = C5

EH (bet)
Man        2480 = D#7    1840 = A#6    530 = C5
Woman      2990 = F#7    2330 = D7     610 = D#5
Child      3570 = A7     2610 = E7     690 = F5

AE (bat)
Man        2410 = D7     1720 = A6     660 = E5
Woman      2850 = F7     2050 = C7     860 = A5
Child      3320 = G#7    2320 = D7    1010 = B5

AA (hot)
Man        2440 = D#7    1090 = C#6    730 = F#5
Woman      2810 = F7     1220 = D#6    850 = G#5
Child      3170 = G7     1370 = F6    1030 = C6

AO (caught)
Man        2410 = D7      840 = A5     570 = C#5
Woman      2710 = E7      920 = A#5    590 = D5
Child      3180 = G7     1060 = C6     680 = F5
=
UH (full) 
Man        2240 = C#7    1020 = C6     440 = A4
Woman      2680 = E7     1160 = D6     470 = A#4
Child      3310 = G#7    1410 = F6     560 = C#5
=
UW (good) 
Man        2240 = C#7     870 = A5     300 = D4
Woman      2670 = E7      950 = A#5    370 = F#4
Child      3260 = G#7    1170 = D6     430 = A4
  

For creating patches based on these values, ideally you want an architecture like this:

                        +-------+     +---+
                  +---->| BPF 1 +---->| M |
                  |     +-------+     |   |
                  |                   | I |
                  |     +-------+     |   |    +-----+   +--------+
Pulse wave osc ---+---->| BPF 2 +---->| X +--->| VCA +-->| Chorus +--->
  (pick best      |     +-------+     |   |    +-----+   +--------+
   sounding fixed |                   | E |
   duty cycle)    |     +-------+     |   |
                  +---->| BPF 3 +---->| R |
                        +-------+     +---+  

Whatever software or synth you are using, the chorus effect at the end is vitally important for realism. If you turn the chorus off on the VP-330, the illusion of human voices TOTALLY disappears. The chorus units on the VP-330 are very complex, but I have not studied them in detail. Regular chorus effects seem to work ok on other synths.

On the JD-800, it's not possible to implement the ideal architecture, but you can do this instead:

Tone +---------+   +-------+   +-----+   +---+
A    | Pls osc +-->| BPF 1 +-->| VCA +-->| M |
     +---------+   +-------+   +-----+   |   |
                                         | I |
Tone +---------+   +-------+   +-----+   |   |   +--------+
B    | Pls osc +-->| BPF 2 +-->| VCA +-->| X +-->| Chorus +--->
     +---------+   +-------+   +-----+   |   |   +--------+
                                         | E |
Tone +---------+   +-------+   +-----+   |   |
C    | Pls osc +-->| BPF 3 +-->| VCA +-->| R |
     +---------+   +-------+   +-----+   +---+  

Here are sound clips of my JD-800 patches using the above formant values:

Male Ahh	(67K mp3)
Female Ahh	(61K mp3)
Child Ahh	(56K mp3)
Male Eee	(58K mp3)
Female Eee	(52K mp3)
Child Eee	(47K mp3)

The "Eee" sounds can be used in combination with the sustain pedal and the "Pitch Random" slider to produce Ligeti-like choir effects:

Hear it: (486K mp3)

My JD-800 Page

Here is a ZIP containing a syx file with all my JD-800 choir sounds: (1K ZIP).

I used the JD-800 Patch Organizer written by Laurent Lecatelier-Dudec, which can be downloaded from Oliver Ganz's page.