Saturator plugins - time vs frequency domain?

[kylen]

OK - thanks again guys. Have been doing some homework, reading this glossary:
http://www.zytrax.com/tech/audio/glossary.html

Things were a bit easier when it was tubes vs transistors vs tape...

But here we have dsp and as meloco_go mentioned there is a misunderstanding. Me mostly.

I think what I really am wondering is if there are any spectral Saturators?
[Not 4-6 multi-band but 1024 or more 'bands', whatever that's called]

Trying to catagorize frequency/time domain was not a good idea since I haven't got a grasp of it yet. I did pick up a good book at safari online called DAFX - Digital Audio Effects: http://www.dafx.de/ could take a few weeks to get thru that one!

[kvaca]

OTOH frequency domain procedures (such as FFT) does not work as saturation, they do not cause spectrum broadening.

thanx for explanation...I was afraid of this too

[@midnight]

I would say its in the time domain if it uses an envelope follower or something that changes over time.

??
many LP equalizers works in time domain without using this...

without using what?

...envelope followers

"envelope follower or something that changes over time

what part of LP equalizer changes over time?

atleast my understanding of "time domain" is it is implying a change in the "effect" over time

for example, LFO is time-domain by it's very nature

[kvaca]

I would say its in the time domain if it uses an envelope follower or something that changes over time.

??
many LP equalizers works in time domain without using this...

without using what?

...envelope followers

"envelope follower or something that changes over time

what part of LP equalizer changes over time?

...exactly

but if you dont believe me just contact the devs of these equalizers /all not FFT based LP equalizers/ and ask them why are they described as working in time domain if you think its impossible...

[@midnight]

i asked you

"what part of LP equalizer changes over time?"

and your answer is

"exactly"

?

[lfm]

...exactly

but if you dont believe me just contact the devs of these equalizers /all not FFT based LP equalizers/ and ask them why are they described as working in time domain if you think its impossible...

Isn't time domain that there is some kind of phase shift going on, as analog filters do etc?

When talking about speakers(monitors) for mixing you want as much consistency in both frequency and time domain as possible to create a neutral sound.

When doing effects, you want the opposite, simply put - you want to manipulate what is going on.

Saturators are to add harmonics of some kind if to emulate tube or tape.

You try to identify what is fundamental frequencies, and add a certain amount of multiples of that frequency(harmonics). Being successfull adding mostly even multiples(octaves) of fundmental frequencies you get a warmer sounding result. If adding too much odd multiples you get harsch.

Any timbre of an instrument is both even and odd harmonics - that's why one instrument sound different from another.

By adding mostly even harmonics, is like also playing the same note one, and two octaves or more at the same time - giving a fuller sound. But if not to destroy character of instrument alltogether - you add parts of the odd harmonics as well.

Tubes create mostly even harmonics, tape create mostly even, but to some extent more odd as well, compared to tubes.

Is there any dsp processing that is not both in frequency and time domain - at least if to emulate analog stuff?

[Gamma-UT]

I think what I really am wondering is if there are any spectral Saturators?
[Not 4-6 multi-band but 1024 or more 'bands', whatever that's called]

Trying to catagorize frequency/time domain was not a good idea since I haven't got a grasp of it yet. I did pick up a good book at safari online called DAFX - Digital Audio Effects: http://www.dafx.de/ could take a few weeks to get thru that one!

The only saturator I can think of that might work spectrally is Waves Maxxbass. The patent expresses what it does in terms of frequencies but I suspect that for computational reasons it does it time domain anyway like the other saturators and simply filters out the fundamental used to generate the harmonics.

Saturation is really just a means to an end: getting higher frequency harmonics into a signal. It does this by simply flat-topping a waveform - sine goes squarish, which adds loads of odd harmonics. Other types of waveshaper will give rise to other harmonics. Tube simulations etc do more complicated stuff. But it's so much simpler in the time domain that doing it any other way seems overly complicated. OTOH, I could see that if you wanted much tighter control over the harmonics generated you might go into the frequency domain, pick out your frequencies of interest and then boost harmonics of those. The 'wave brushes' you get in things like Virsyn's Cube or Metasynth do this. The wave transforms in Zebra could function as another example but I honestly don't know how Urs implemented those - I'm assuming they are done in the frequency domain and converted but it could be done another way. Time-domain and frequency domain are just two different ways to handle signals and the choice is one of expediency - you could process LFOs in the frequency domain, it's just a fricken' long-winded way to go about it.

But, to meloco_go's point, I think in the frequency domain at this point we've pretty much lost touch with the idea of 'saturation' - it's just homing in on the harmonics there.

[kvaca]

i asked you

"what part of LP equalizer changes over time?"

and your answer is

"exactly"

?

I got "EXACTLY" the same question when thinking about your definition of time domain /see above/...

To be as clear as possible:
obviously NO part changes and NO followers involved...in these equalizers...but still they are described working in time domain...

[kvaca]

Isn't time domain that there is some kind of phase shift going on, as analog filters do etc?

not necessarily

Saturators are to add harmonics of some kind if to emulate tube or tape.
You try to identify what is fundamental frequencies, and add a certain amount of multiples of that frequency(harmonics). Being successfull adding mostly even multiples(octaves) of fundmental frequencies you get a warmer sounding result. If adding too much odd multiples you get harsch.

I dont know any single saturatur which can identify fundamental frequency,and you cannot do that either becouse these frequencies are continuously changing over time in majority of music...

adding mostly even order harmonics CAN sound as harsh as adding mostly odd harmonics.../becouse of intermodulation distortion,aliasing etc.../

Tubes create mostly even harmonics, tape create mostly even, but to some extent more odd as well, compared to tubes.

I would not say "mostly even"...there is always nice balance between even and odd harmonics created by that devices...at least good ones

[lfm]

I dont know any single saturatur which can identify fundamental frequency

adding only even order harmonics CAN sound as harsh as adding only odd harmonics.../becouse of intermodulation distortion,aliasing etc.../

How would you know what they do and not, exactly?
Do you run tests and check an analyzer?

Many have patented algorithms, like SoftTube stuff etc.

At some point adding multiples will become 7th, and 9th notes and anything in between in complex material, so yes, that is true. You change character too much of the sound if just going wild adding stuff - even if even. And as you say create unwanted distortion.

But identifying what is fundamental frequency of an instruments note, withing polyphonic material you can select what to add, and where. So you can search from even and odd distances from fundamental, and know this is the same instrument - or make assumption. It may be harmonics of another instruments as well - so there is the complexity of polyphonic material - identifying what will be pleasing to ear if adding content. So assumptions of levels at even and odd distances from fundamental can make you distinguish instruments and voices.

My guess is that those that sound good - do it right. The knowhow of this is worth a lot of money.

Melodyne developers probably have a lot of knowledge in the area, handling polyphonic material identifying notes - so my guess is that they should be able to make good saturation stuff as well - if they haven't already.

I remember testing TRacks 10 years ago, and it added so much that it became musch. So they used rather simple algorithms then was my conclusion.

I have, so far without success, been trying to get something nice from Waves Aphex Aural Exciter. But keep experimenting. Their manual is not very helpful - just saying that input levels also affect result.

But Kramer Master Tape, was real easy to get nice sound from. NLS as well. HLS EQ is nice either way you use it. You can go crazy on mids without causing harschness - it just become richer.

I don't know if Waves have used their own QClone to do these emulations, or if it's algorithms from scratch.

But it sure is a scientific field of it's own - knowing how to do this.

[Gamma-UT]

I dont know any single saturatur which can identify fundamental frequency

adding only even order harmonics CAN sound as harsh as adding only odd harmonics.../becouse of intermodulation distortion,aliasing etc.../

How would you know what they do and not, exactly?
Do you run tests and check an analyzer?

A saturator has no need to find the fundamental frequency. It simply crushes the peaks - the strongest peaks will be those generated by the fundamental and early harmonics. As a result, you get more complex interactions on anything that isn't a pure sine wave. It's hard to see on a triangle or square wave with a spectrum analyser because the harmonics coincide but if you use something like an FM synth with two oscillators in parallel set inharmonically you can see how the saturation creates new peaks derived from all the strong peaks in the signal, not just the fundamental.

[kvaca]

But identifying what is fundamental frequency of an instruments note, withing polyphonic material you can select what to add, and where. So you can search from even and odd distances from fundamental, and know this is the same instrument - or make assumption. It may be harmonics of another instruments as well - so there is the complexity of polyphonic material - identifying what will be pleasing to ear if adding content. So assumptions of levels at even and odd distances from fundamental can make you distinguish instruments and voices.
My guess is that those that sound good - do it right. The knowhow of this is worth a lot of money.

at least nice idea for whole new generation of saturation plugins...but Im pretty sure it will be very hard - if not impossible - to create such plugins to work in realtime

[Gamma-UT]

But identifying what is fundamental frequency of an instruments note, withing polyphonic material you can select what to add, and where. So you can search from even and odd distances from fundamental, and know this is the same instrument - or make assumption. It may be harmonics of another instruments as well - so there is the complexity of polyphonic material - identifying what will be pleasing to ear if adding content. So assumptions of levels at even and odd distances from fundamental can make you distinguish instruments and voices.
My guess is that those that sound good - do it right. The knowhow of this is worth a lot of money.

at least nice idea for whole new generation of saturation plugins...but Im pretty sure it will be very hard - if not impossible - to create such plugins to work in realtime

Audio-to-MIDI guitar converters can do some of this (with a little latency, as it takes time for the string vibrations to settle enough to give a reliable fundamental).

Also, check out Sound Radix' SurferEQ. It will track frequency peaks and boost harmonics of them (it's an EQ so it's not actually generating any). It's really quite neat.

EDIT: misread the post you were replying to. That really is quite tricky.

[meloco_go]

You try to identify what is fundamental frequencies, and add a certain amount of multiples of that frequency(harmonics).

This is a serious misunderstanding of basic math behind DSP. You do not identify fundamental frequencies to add harmonics, any waveshaping process adds harmonics that are related to the frequency content of incoming signal automatically.
Say you have a simple waveshaping function that takes a 3rd power of an incoming signal (y=x^3). What will happen if you use that fuction on a sin(x) signal?
y=(sin(x))^3=(3sin(x)-sin(3*x))/4
You see that sin(3*x) appeared? That is a third harmonic of an incoming signal.

Now, you may think of a processor that would track the pitch (like the Melodyne you mentioned) and generate harmonics based on that. But there is a serious problem with such idea -- the time and frequency domain resolution is inversly proportional (basic math principle), so if you have good resolution to identify frequency precisely your process won't be able to track fast pitch changes correctly, and not even think of something noise like -- like a snare rimshot.

[@midnight]

i asked you

"what part of LP equalizer changes over time?"

and your answer is

"exactly"

?

I got "EXACTLY" the same question when thinking about your definition of time domain /see above/...

To be as clear as possible:
obviously NO part changes and NO followers involved...in these equalizers...but still they are described working in time domain...

ah, gotcha.

i really have no idea what goes in with linear phase EQ.

to be honest, i have literally never used one in my music, I just haven't needed a purpose. I guess I am not doing much critical/surgical work in my music.

I don't really aim to have the most clean/perfect sounding mix, in fact sometimes i deliberately don't EQ things because I want the sound to be "imperfect" in a way that adds an emotional cue, for example overly dark and muddy piano, can be a problem, or that same overly dark muddy piano can be intentional sound design choice that gives the listener a certain type of psychological response "this piano sounds clausterphobic" etc...

I think the search for perfect sound is a misguided one, but I am getting way off-topic now.

In fact, I think I probably dont even truly know what "time-domain" means, I have thinking I have an overly simplistic model of it in my head.