Removing fundamental frequency with keytracking filter

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Ja ja
Posts: 17
Joined: 02 Feb 2023

14 Mar 2023

Hi all,

I'm looking for a method to remove the fundamental frequency from a sound by using a keytracking high pass filter. I know something similar could be done by using an additive synth, but I would like to use this method so I can apply it to any kind of sound.

For example: a Subtractor bass sound, playing a A-1 note (55Hz) and a MClass Equalizer with a LPF frequency set around 82,5Hz (1,5 x the fundamental frequency), filtering away all frequencies below the first harmonic. When playing a A-2 note (110Hz), I would like the LPF frequency to move to 165Hz. When playing any other note, the ratio between the fundamental frequency of the note played and the LPF frequency should be kept constant at a factor 1,5. I tried using a combinator for this and assigning the Key as a Source for the LPF frequency. I figured playing with the Key Range, Target Range and Source Range would do it, but I could not get it to work.

Things I ran into where:
1) Settings of the ranges in the combinator cannot be set precicely (I cannot fill in the exact number I want to use).
2) The scale of the LPF frequency is not linear.

Does anyone know a method to achieve this in Reason? In this example a MClass EQ is used, but it could be any kind of filter that does the job.

Thanks in advance.

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dioxide
Posts: 1781
Joined: 15 Jul 2015

14 Mar 2023

Selig's Coloring EQ can track MIDI note to frequency.
Taking things even further, every band can be “Played” by either MIDI notes or CV/Gate signals. This allows the creation of “Tracking EQs”, tuned resonating filters, note gated EQ with velocity, and more.
https://www.seligaudio.com/products/coloringeq.html
https://www.reasonstudios.com/shop/rack ... oloringeq/

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huggermugger
Posts: 1294
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14 Mar 2023

A quibble, but I think you mean a HPF, not a LPF.

Ja ja
Posts: 17
Joined: 02 Feb 2023

15 Mar 2023

dioxide wrote:
14 Mar 2023
Selig's Coloring EQ can track MIDI note to frequency.
Taking things even further, every band can be “Played” by either MIDI notes or CV/Gate signals. This allows the creation of “Tracking EQs”, tuned resonating filters, note gated EQ with velocity, and more.
https://www.seligaudio.com/products/coloringeq.html
https://www.reasonstudios.com/shop/rack ... oloringeq/
Thanks for the tip! Did not know that.

Ja ja
Posts: 17
Joined: 02 Feb 2023

15 Mar 2023

huggermugger wrote:
14 Mar 2023
A quibble, but I think you mean a HPF, not a LPF.
Yes, you are right. My mistake. I got it mixed up with "Lo Shelf" from the MClass equalizer. Thanks for pointing that out.

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deeplink
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15 Mar 2023

You can try it with an additional EQ / filter as above.

But know that it won't be polyphonic - so try use the keytracking in Subtractor, Europa etc. (in the actual device/VST) instead where possible.

Europa is pretty neat as you don't need to use a filter - just remove the first harmonic in Harmonics section.
Get more Combinators at the deeplink website

Ja ja
Posts: 17
Joined: 02 Feb 2023

16 Mar 2023

Hi deeplink,

Thank you for your reply. I'm not able to figure it out though. Maybe you could help me a bit more.
deeplink wrote:
15 Mar 2023
try use the keytracking in Subtractor, Europa etc. (in the actual device/VST) instead where possible.
Do you mean the Kbd-knob for Subtractors filter 1? I looked into this. This seems to do something similar as I'm looking for but not as precise as I would like it. Is this what you meant or is there a different method?
deeplink wrote:
15 Mar 2023
just remove the first harmonic in Harmonics section.
I tried fiddling around with the spectral filter and the harmonics settinds in Europa but I wasn't able to only remove the fundamental frequency. Could you please explain which settings you use?

Thank you in advance.

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selig
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16 Mar 2023

Ja ja wrote:
16 Mar 2023
I tried fiddling around with the spectral filter and the harmonics settinds in Europa but I wasn't able to only remove the fundamental frequency. Could you please explain which settings you use?

Thank you in advance.
I did it by using ENV 4 mode, and drawing an envelope that is basically the lowest level for the first 1/4, then a step up to the middle level. Then play a saw wave, dial up the Q/Depth, then adjust the frequency until the first harmonic disappears. You can watch the spectrum display when doing this, but it is a pretty obvious effect easy to hear by ear IMO.
The cool thing with Europa is you can add the fundamental on the second engine, and a sub octave 'harmonic' on the third for a really big sounding bass. Be sure to click on PHASE SYNC for the sine oscillators, and run them all through the main filter with DRIVE set to 50% for a even fatter sound.
As a bonus, you can add UNISON on the first oscillator and spread it wide, with the fundamental still clean and clear and right up the middle.

In Subtractor use the Notch filter and set the Frequency to 58, Q to 110, and Kbd (key tracking) to 127. It's not as perfect as Europa but it works well.

For other sounds I would use ColoringEQ with the notch filter tracking the keyboard in a combinator, with either the notch filter with full Slope (depth) and a Q of .83, or the first parametric with full negative gain and the same Q (around .83). You can also use two parametrics set to the same setting to get 48 dB reduction if needed.

Of all of these Europa is the easiest and 'cleanest' sounding IMO, plus it's polyphonic and at the voice "engine" level meaning you can apply it to one Engine and not the other two.

Here's the Europa patch I made using the "missing fundamental" filter I described above:
https://www.dropbox.com/s/97n6l9vptcrw5 ... h.zip?dl=0
Selig Audio, LLC

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deeplink
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16 Mar 2023

Overall you can follow Selig's post above. However to answer your questions;
Ja ja wrote:
16 Mar 2023
Is this what you meant or is there a different method?
Yes that is what was meant. I have not tested or compared the accuracy of such Knobs (whether on Subtractor or elsewhere), but I just assumes it works as intended when the knob is at 100%.
Ja ja wrote:
16 Mar 2023
Could you please explain which settings you use?
In my case, I would generally go straight for the Harmonic Mixer - on the "1-8" Mode.
With Position all the way to the left, this focuses on the first harmonic.
Then with the amount you can mix this first harmonic (either muted or solo'd)

As Selig said, with Europa you're Wave Engine, (Osc, Mod, Spectral Filter and Harmonics) it is the most cleanest that you will get, as you're still only working in the "DSP" domain and the data has not yet been translated to audio.
Get more Combinators at the deeplink website

Ja ja
Posts: 17
Joined: 02 Feb 2023

18 Mar 2023

Hi Selig,

Thank you very much! Very clear example. Took me some time to figure out that Envelope 4 can be selected directly as spectral filter. The Dropbox example helped a lot to understand it.
selig wrote:
16 Mar 2023
In Subtractor use the Notch filter and set the Frequency to 58, Q to 110, and Kbd (key tracking) to 127. It's not as perfect as Europa but it works well.
As you suggested I used the spectral analyser to see what's happening. I noticed a difference between Europa and Subtractor, which I cannot explain. While in Europa the fundamental seems to be always filtered away, in Subtractor the fundamental seems to be present when playing a note and then fading away. Even when the Filter Envelope Amount is set to 0. Do you perhaps know where this difference in behavior is comming from? For Subtractor I used the Init patch with your settings applied.

Thank you in advance.

Ja ja
Posts: 17
Joined: 02 Feb 2023

18 Mar 2023

Hi Deeplink,
deeplink wrote:
16 Mar 2023
In my case, I would generally go straight for the Harmonic Mixer - on the "1-8" Mode.
With Position all the way to the left, this focuses on the first harmonic.
Then with the amount you can mix this first harmonic (either muted or solo'd)
Thanks a lot for the explaination. I got it working. Very cool to see that multiple approaches are possible with Europa to remove the fundamental. Helped me a lot.

AnotherMathias
Posts: 213
Joined: 29 Sep 2020

18 Mar 2023

If you wanted to remove the fundamental from NN-XT or NN19 (and I'm guessing also Mimic), then all you'll need is to set the filter to notch, key tracking to 100%, and tune the cutoff to the fundamental. I do it pretty often, works great!

A fun thing to do when you do that is to put some LFO modulation on the cutoff. Depending on the sample material you get a nice phase-y tremolo, especially useful in NN19 that doesn't have any LFO->amp modulation.

Ja ja
Posts: 17
Joined: 02 Feb 2023

19 Mar 2023

Hi AnotherMathias,

Thanks for your reply, got it working in NN19 and Mimic. Also thanks fot the tremolo tip!

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