Exciter

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gilzad
Posts: 92
Joined: Wed Dec 19, 2012 6:46 am

Exciter

Post by gilzad »

MetaModules is a killer-feature. Today I'm bringing you an Exciter.

(Right-Click to save)
Exciter Example
SunSynth Module | Simpler old version
LQ SunSynth Module

Background
A classic Exciter creates harmonics in the audible high frequency band (around 8 kHz and above). So this is simply done by applying Distortion behind a HighPass-Filter.
Some time in the early 2000's, I guess, I saw this "Waves MaxxBass" plugin. A DirectX/VST-plugIn that would create harmonics in the bass range. Later, at a friends house, I saw the "SPL Vitalizer" that magically enhanced the bass range of a very narrow-sounding Kraftwerk song. Now even Renoise offers a 3-Band Exciter. True, if we can create harmonics in the high-band, why not create harmonics in many bands? Enough motivation for me to test that!

When handling frequencies, I find it pretty handy to control deep lows, low mids, mids, high mids and the highs separately. So I decided I wanted to have five bands for our Exciter.

What is it good for?
It's the magic tool that adds *ooomph* to your bass, if nothing helps (SPL Vitalizer, MaxxBass, etc.).
It's the magic tool that makes your vocal recordings become crystal clear (Classic Exciter).
It's the magic tool that creates frequencies, where they are missing. E.g. turn a 22kHz recording into acceptable 44kHz.
It's the magic tool being abused in broadcasting to add brilliance to advertisings and to make sure the sound gets pierced into ears.

The example file
The example file comes with a little loop sample, an excerpt of 'Idris Muhammad - Hard To Face The Music'. This is a recording from the 70s and lacks bass in the subs, also the highs are a bit too queeky while they lack brilliance. So it has to be excited! :) If you play that pattern, you will see the selfmade Exciter in action. To compare how the sample would sound without it, simply unmute the 'COMPARE' DSP. It makes sure you only hear the dry source and automatically mutes the output of the excited sound. I'm a little proud of this one ;)
If you really opened the example file to see the inside, you'll notice that I also applied filters behind the Distorion. This is something I often do, when I hard-compress the low bands to cut any distortion-artifacts. Especially in the low bands this is helpful. Now Distortion exactly what is applied to each band. So we need to make sure that the harmonics remain in their bands. Else, you won't get the fine, saturated sound of an exciter. You'll just have a distortion. Theoretically I could live without the post-filter in the high band but the crossband-frequencies of the filters simply force us to keep everything separated. After many tests, I chose a roll-off of 12 dB/Octave. That's 24 dB, if you consider the post-filters. Any higher edge would create horrible gaps in the cross-over frequencies. Even the way it is now, there are some minor gaps, but once you create the harmonics, they don't matter anymore. You'll also see that I softenened the cross-over-bands by 10 Hz.
While playing with the knobs you might come to think "It's coloring the sound, it's just an Equalizer!". No, it's not. We're not balancing existing frequencies by making them louder or quieter. We're creating new freuqencies. ;)
Another question that might come up, is why I didn't use the Filter's native band-pass option. Well, I didn't see any way to set its band width. Shame on me, if I actually could, but missed to see it.

What is happening?
First the sound is being separated into the five mentioned frequency bands: lows (-70Hz), low mids (70 - 300 Hz), mids (300 - 2 KHz), high mids (2 KHz - 8 KHz) and highs (8 KHz and above).
Then, the actual part of the Exciter, the Distortion, is applied to each band. That's the part, where the harmonics come into being. Ever turned a sine-wave into a pulse-wave just by distorting it? So, the sine-wave would only have one frequency but a pulse-wave will have the sine's frequency and many harmonics => more frequencies! That's what the exciter does.
Finally, the excited bands will be will be narrowed into their range again. So you only hear harmonics inside each band and not an actual distortion.


The SunSynth module
Currently we only have a limited amount of controls in a MetaModule. So I had reduce the options to the excitement you can apply to the sound. But I had to think of volume levels that will hopefully balance things out in most situations.
Maybe NightRadio can give us dynamically addable/removable controls for the MetaModule some time. Then the Exciter will offer both: A knob for the excitement and one for the volume of each band.
Currently you have a "Feed" knob, that can control the loudness on the input of the Exciter and the Distortion of the five bands.

Hope you find this any useful!

Have a happy new year :)

gilzad

edit: Added a low-quality version for slower devices. Updated the HQ-version to support output-controls, too. The old version is still linked here, should you prefer a simpler version.
Last edited by gilzad on Thu Jan 17, 2013 5:32 am, edited 1 time in total.
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NightRadio
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Re: Exciter

Post by NightRadio »

Wow! I need to check this :)
Happy new year! :)
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samrai katt kovboy
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Re: Exciter

Post by samrai katt kovboy »

tried it just now and it works nicely thank you very much!
SOOOOOOOOOOOOOOO MANY CIRCLES
Oliv
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Joined: Wed Oct 31, 2012 4:30 am

Re: Exciter

Post by Oliv »

I usually don't contribute much to any forum, but you, my man, have my congratulations.

Sharing the theory and the reasoning behind this very impressive module is just the icing on the cake.

Well done.
gilzad
Posts: 92
Joined: Wed Dec 19, 2012 6:46 am

Re: Exciter

Post by gilzad »

Thank you guys, really appreciace!
After having posted another artice/module (Multiband Limiter), I think I'll give it a rest now. ;)
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SolarLune
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Re: Exciter

Post by SolarLune »

Wow, this really does make a fairly large difference. Really cool effect! Great work, seriously!
convergent
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Re: Exciter

Post by convergent »

This a pure essence of SunVox'ing — I'm really excited (ha-ha :D) someone did this.

Popular software (Ableton, Logic, FL, etc) now turns these simple yet elegant sound-engineering techniques into black boxes: you have abstract block which does "stuff" and you have no idea how it works. As result, music production becomes magic. I'm freshman in electronic music — half year ago I started making music with my first DAW (it was SunVox) and I have really poor understanding of sound design (mastering, EQing, etc) — your 3 examples explained alot, thank you. Looks like you're pretty old and wise guy in this and you know how signal processing is done. I'd be glad to learn more, if you've got more %)
organic io
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Re: Exciter

Post by organic io »

convergent wrote: Looks like you're pretty old and wise guy in this and you know how signal processing is done. I'd be glad to learn more, if you've got more %)
It was hearing Gilli's song "Magic Piano" http://www.gilzad.de/inorganic/audio/Th ... 0Piano.ogg back in 2005 which is what convinced me that Renoise could be used to make professional sounding tracks. :D

Of course he and I have become friends since then and he is just an all around great guy too :)

P.S... The fact that he is inorganic and I am organic... I don't know why he doesn't like organs. Whatever!!! :P
gilzad
Posts: 92
Joined: Wed Dec 19, 2012 6:46 am

LQ-version and update available

Post by gilzad »

Thank you so much, everyone!

@SolarLune: Really appreciate your work on the tutorials!
@convergent: I'm looking forward to hear some music from you soon! I'm not that old, though. Okay, I am, but just let me pretend I'm 29. I'll feel better then. And yes, I've got more! Check out the Mid/Side DSPs.
@Scott: Thanks for the promo :) Now you brought SunVox to SDC and made me check it out.

I've added an LQ-version of the Exciter to the first post. It shouldn't sound much worse and it should run faster on slow devices. Don't expect the HQ and LQ versions to sound the same though. As soon as you change the default parameters, they'll show different characters. Even with the default-values the LQ-version colors the sound more.

What I did was:
Remove one amplifier
Turn all filters from HQ-mode to LQ-mode
Invert the signal of each LQ-filter, mix it to the HQ-version and carefully change the cutoff until the least amount of residue would remain to get as close as possible to the HQ cutoff.

This was quiet some work, but after Nightradio had explained the guts of the filters, I couldn't just throw that knowledge away and not create a faster version.
If anyone finds some use for a mono version and bothers to create it, I'd be glad to link that version here. You'd only need to switch all the filters to HQ mono in the HQ-version and to LQ-mono in the LQ-version. The hard part (recreate cutoff) is done already.

Furthermore, the HQ-exciter has been updated to offer output-volumes for each band now. However, one might find it tricky to handle so many controls. Therefore the old version with less controls is still linked in the article.

Best,

gilzad
Pioneer
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Re: Exciter

Post by Pioneer »

Wanted to thank you for this. It makes a huge difference on kicks, bass and snare for me. I will probably run 3-5 instances of this module on all my productions..thanks!

:Bravo:
convergent
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Joined: Fri Aug 17, 2012 3:36 am

Re: Exciter

Post by convergent »

Me too, exciter helps me now to make poor brass samples sound better and the other module (multiband-smth..) is really good for pre-mastering. For some reason, non-chiptune sunvox songs have much less loudness (with the same volume) than others. Or I just don't cook them right.
Pioneer
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Re: Exciter

Post by Pioneer »

I filter and effect in sunvox, but dump to DAW for further EQ/reverb/ mixing. Perfect combo.
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