Synth/Effect that can subtract spectrum A from B in real time?

VST, AU, AAX, etc. plug-in Virtual Instruments discussion
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snoddas
KVRist
73 posts since 5 May, 2006 from Uppsala, Sweden

Post Mon Apr 23, 2018 1:07 am

Hi folks,
Playing with ReaFir and enjoying building spectrums for eq:ing. Are there any vstis that can do the same thing, ie build/load a spectrum B and subtract B from other spectrum A. Any basic vst that can hold multiple spectrum B:s so one could choose/play different B:s to subtract from A? Sort of like an 'inverted' vocoder.
Anything similar of interest!
Regards,
/S

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whyterabbyt
Beware the Quoth
26115 posts since 4 Sep, 2001 from R'lyeh Oceanic Amusement Park and Funfair

Re: Synth/Effect that can subtract spectrum A from B in real time?

Post Mon Apr 23, 2018 2:37 am

The thing about an impulse response is that it is effectively subtracting from the effected signal's spectrum. The way it basically works is that only the frequencies the IR and the signal have in common remain, the rest are lost. The ones that remain are 'multiplied', so the spectrum of the IR is 'superimposed' on the signal.

(The inverse of an IR would be [1-IRn] for each sample n of the IR, he says off the top of his head without thinking about it properly)

Not sure of which convolvers can switch IRs on the fly, its a heavy process so there's a latency involved. I guess one option is could stack up multiple convolvers in a host like Bidule, though, and change which one you're routing to on the fly.
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Mushy Mushy
KVRAF
9930 posts since 7 Sep, 2008

Re: Synth/Effect that can subtract spectrum A from B in real time?

Post Mon Apr 23, 2018 3:00 am

Isn’t this simply a case of AM and automating the volume of osc 2?

EDIT: :dog: You're referring to EQ not synthesis.
Last edited by Mushy Mushy on Mon Apr 23, 2018 7:17 am, edited 1 time in total.
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Steve1974
KVRist
36 posts since 13 Sep, 2014 from Moscow, Russia

Re: Synth/Effect that can subtract spectrum A from B in real time?

Post Mon Apr 23, 2018 6:46 am

Maybe Thorn by Dmitry Sches?
It has Harmonic Filter.
Sorry for my bad English. I'm not a native speaker.

yellowmix
KVRian
698 posts since 11 Aug, 2012

Re: Synth/Effect that can subtract spectrum A from B in real time?

Post Mon Apr 23, 2018 7:15 am

Well, unless you're dead-set on using FIR for EQing, consider the more CPU-friendly IIR method with something like Trackspacer from Wavesfactory.

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snoddas
KVRist
73 posts since 5 May, 2006 from Uppsala, Sweden

Re: Synth/Effect that can subtract spectrum A from B in real time?

Post Mon Apr 23, 2018 12:27 pm

Thanks fir ( :o ) the input. I'll look into the suggestions and see if they lead anywhere useful. I tried out the thorn synth for a one synth challenge and was impressed.
/S

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Tj Shredder
KVRian
1254 posts since 6 Jan, 2017 from Outer Space

Re: Synth/Effect that can subtract spectrum A from B in real time?

Post Mon Apr 23, 2018 2:29 pm

A modular built vocoder should do it, you have to invert the spectrum which is applied to the carrier... Maybe in the reaktor library is something like that...

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snoddas
KVRist
73 posts since 5 May, 2006 from Uppsala, Sweden

Re: Synth/Effect that can subtract spectrum A from B in real time?

Post Mon Apr 23, 2018 3:36 pm

[quote="Tj Shredder"]A modular built vocoder should do it, you have to invert the spectrum which is applied to the carrier... Maybe in the reaktor library is something like that...[/quote]
So you would invert the modulator signal before feeding it to the vocoder? And the vocoder would need quite a few bands.

Chandlerhimself
KVRian
821 posts since 19 Dec, 2013 from Japan

Re: Synth/Effect that can subtract spectrum A from B in real time?

Post Mon Apr 23, 2018 6:35 pm

I believe the convolution mode in MPowersynth’s OSC will do this.

counterparty
KVRist
116 posts since 21 Jul, 2016

Re: Synth/Effect that can subtract spectrum A from B in real time?

Post Mon Apr 23, 2018 8:42 pm

Do you mean something like WavesFactory Track Spacer? It functions like a multi-band EQ that removes the frequencies of a sidechain track from the track it's applied to.

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Tj Shredder
KVRian
1254 posts since 6 Jan, 2017 from Outer Space

Re: Synth/Effect that can subtract spectrum A from B in real time?

Post Tue Apr 24, 2018 5:04 am

snoddas wrote:
Tj Shredder wrote:A modular built vocoder should do it, you have to invert the spectrum which is applied to the carrier... Maybe in the reaktor library is something like that...
So you would invert the modulator signal before feeding it to the vocoder? And the vocoder would need quite a few bands.
It has to be flipped around some arbitrary level, the places where a frequency would be boosted, you lower it and vice versa. This is something to experiment with. Basically you are asking for a filter controlled by a signal...
I think in Bitwig you could patch something like that together...

aumordia
KVRist
260 posts since 16 Jun, 2015

Re: Synth/Effect that can subtract spectrum A from B in real time?

Post Tue Apr 24, 2018 9:51 am

harmor
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