Formant Filter for Octatrack

Elektron Gear Octatrack
#1

Just a little tip for people who would like to do some vocaloid processing on their OT… it is possible to make formant filters on it, by using the parametric EQ on neighbour tracks and following this chart: https://www.classes.cs.uchicago.edu/archive/1999/spring/CS295/Computing_Resources/Csound/CsManual3.48b1.HTML/Appendices/table3.html

I found I got best results using two identical EQs in series per neighbour track (2 tracks in total, making 4 bands of EQ), using the spectrum analyser in my DAW to make sure I was getting at the right frequencies.

I also found it very nice to set up scenes for each vowel sound and morph between them!

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VP-330 human voice emulation?
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#2

Any chance you could post some sound examples?

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#3

Here you go, very quickly done with OT just playing a square wave, playing with crossfader (turn volume down before you hit play!)

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#4

Thanks, it’s a good idea.
I can’t use my DAW computer these days. Would you share your eq settings to match frequencies ?

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#5

OK, here you go! Just some more info:::

  • When setting this up, I have the Q value of the EQ set to 127, to get those sharp boosts that make up the formant filter.
  • The source material you are working with will have a big bearing on the effectiveness of this. Preferably it will be something that has a lot of upper harmonic material. With this in mind it can be a good idea to put a LOFI effect before your EQs to add harmonic material.
  • Try resampling the formant sounds you get and repitching them etc etc, have fun with it

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#6

Thanks ! Don’t you lower the volume VOL ?
Yesterday I made tests with wrong frequencies on a white noise sample, with a lot of harmonic material :wink:

#7

sorry yes…edited for clarity… I’ve been sick on the couch all week, at least that’s my excuse…

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#8

Windows Xp wallpaper is your remedy ? :sunny:

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#9

it’s one of those classic timeless images, like that one of the big pink sunset, cheesy & comforting & nostalgic all at the same time, so if this doesn’t cure me then i’m afraid nothing will

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#10

Hi. I hope you feel better.
I had very interesting results with your informations, thanks. I found that Q could be lower. I prefered to have 4 different eqs per tracks, then copy track for neighbor.
One track is almost enough.
A saw wave seems better.

I made scenes, and modulated them with random lfos with midi tracks (CC55-56), and used a random speed modulated tri lfo for the CC48 crossfader.

As filters have 2 Q res + Env, I think it’s possible to have better results with them. In order to save tracks, maybe you can use only 2 frequencies.

Screenshot_2017-09-04-10-39-02.png720×1280 71.1 KB

Edit. It works pretty well with 1 regular filter and above frequencies !

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#11

Very clever with the filter, bravo! I’ll give that a try myself!

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#12

It is still better with 4 frequencies.
With filters only you need 2 tracks if you want 4 fqs, with 2 Thru or 2 tracks playing the same sample :
T1 > F1 F2 (+ FX2)
T2 > F3 F4 (+ FX2)

I found interesting to use filter AND eq, in order to use only one track, and be free to chain 2 FX with a Neighbor track :
Filter > F1 F4
EQ > F2 F3
If you place filter after eq, it seems to sound the same.

It sounds different with the filter, especially because of the bandpass. 24db settings accentuate the bandpass.

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#13

Hey - any chance of showing even more in terms of Filter settings, etc?

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#14

I’ll try tonight. Remind me, if not, I’d be interested in testing this again…

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#15

Would really appreciate it, man :blush:. I’m starting to explore the OTs a bit more, cherry picking some of your crazy initiatives :laughing:

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#16

You can thank @sleepystevo!
I can’t remember if I wrote frequency values somewhere. IIRC someine made a sheet with OT filter values and corresponding freqs…

Eq values


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#17

Fantastic - very much appreciated!

#18

I used A and I vowels

F1 is Filter Base
F2 is EQ1
F3 is EQ2
F4 is Filter width
(F1+width=F4, width=F4-F1)

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#19

Just pure gold, man!!!

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#20

Let me know if something is unclear. Maybe I’ll redo or edit the video…

Luckily filter and eq frequencies seem to correspond.
IIRC I used different formant frequencies for my first test a while back…

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