The Waveulator: Two VCA-based Clipper Saturators

Where we discuss new analog design ideas for Pro Audio and modern spins on vintage ones.
User avatar
mediatechnology
Posts: 5473
Joined: Sat Aug 11, 2007 2:34 pm
Location: Oak Cliff, Texas
Contact:

Waveulator Waveforms

Post by mediatechnology »

I made some Waveulator waveform and transfer function oscillograms.

You can see in the high ratio images that there are no hard corners as it clips. The corners are "beveled."

Image
Waveulator Low Threshold High Ratio Waveform

Image
Waveulator Low Threshold High Ratio Transfer


Image
Medium Threshold High Ratio Waveform

Image
Waveulator Medium Threshold High Ratio Transfer


Image
Waveulator High Threshold High Ratio Waveform

Image
Waveulator High Threshold High Ratio Transfer

Some softer saturation:
Image
Waveulator High Threshold Medium Ratio Waveform

Image
Waveulator High Threshold Medium Ratio Transfer

This is with second harmonic added by skewing the negative detector gain:
Image
Waveulator High Threshold Medium Ratio Second Harmonic Waveform

Image
Waveulator High Threshold Medium Ratio Second Harmonic Transfer

This is how the VCA Ec modulation compares to the final output.
Image
Waveulator High Threshold High Ratio Waveform vs VCA Econtrol
TheeAldeen
Posts: 15
Joined: Wed Dec 28, 2022 11:10 pm

Re: The Waveulator: Two VCA-based Clipper Saturators

Post by TheeAldeen »

…i originally valued this modules mainly as an effect, one to be placed on synth bus after the ka width controller — it is very nice to see that it now holds a strong place before the converters. my hat is completely off.
User avatar
mediatechnology
Posts: 5473
Joined: Sat Aug 11, 2007 2:34 pm
Location: Oak Cliff, Texas
Contact:

Re: The Waveulator: Two VCA-based Clipper Saturators

Post by mediatechnology »

I tried to find a good even-order example for a demo and what I settled on was bass guitar.

What I'm finding is that "peak shaving" to produce even-order color doesn't produce color until it becomes a grungy, intermodulated, muddy mess. Works OK on bass and electric guitar but completely tears up most everything acoustic. I don't like it. Used in excess it sounds like an AM station with asymmetric +125/-100% modulation.

Peak shaving odd-order distortion seems to be masked - to a point - by the unadulterated middle portion of the waveform and I think there's some of that masking with even-order as well. When even-order breaks, it breaks hard.

As I've said earlier if there's a lot of clipping and brickwalling in the material it will sound awful when processed by the Waveulator. With clean material going in, large amounts of clipping can be applied without the artifacts becoming objectionable.

I'm starting to see this more as a peak level management tool than an effect.

I could use some solo tracks to process with even-order if anyone has ideas and wants to send me some.
emrr
Posts: 573
Joined: Sun Mar 02, 2008 10:27 pm
Location: NC, USA
Contact:

Re: The Waveulator: Two VCA-based Clipper Saturators

Post by emrr »

I suppose there’s a completely different dynamic in play compared to the usual even order production path. My experience with asymmetric limiting has been CSF Volumax units which are PP transistor circuits, and those are great on things like drums to make greater positive speaker excursion. I can see how this wouldn’t relate since it’s not following an envelope, but instantaneous peaks. Probably still something I’m missing…..
Best,

Doug Williams
Electromagnetic Radiation Recorders
User avatar
mediatechnology
Posts: 5473
Joined: Sat Aug 11, 2007 2:34 pm
Location: Oak Cliff, Texas
Contact:

Re: The Waveulator: Two VCA-based Clipper Saturators

Post by mediatechnology »

Interesting points.
+1 on the speaker ultimately moving out/pressure wave with positive signal polarity.
If the signal is inverted with greater negative excursion what do you hear change?

I found on some examples I could add "point" to drums by compressing the negative peak leaving the positive largely untouched.
My test used compressive distortion on negative excursions by making the positive appear larger without actually adding anything to it.

The Volumax example you gave suggests that maybe I should try expansive distortion - adding harmonics to the positive peak but leaving the negative untouched. In the extreme, expansive distortion sounds like upward expansion/downward gating which can definitely put a point on percussion adding dynamic impact. The two methods, squashing negative versus expanding positive, definitely sound different. Transients are added with the later.

In some of my earlier Waveulator examples I provided a comparison of expansive versus compressive distortion on percussion: https://proaudiodesignforum.com/forum/p ... 046#p12046

The Dave Matthews drum solo is worth listening to again.

Here is a composite file of some Stanley Clark with extreme limiting on negative peaks.

Second Order Sound file: https://proaudiodesignforum.com/content ... arison.wav

Image
emrr
Posts: 573
Joined: Sun Mar 02, 2008 10:27 pm
Location: NC, USA
Contact:

Re: The Waveulator: Two VCA-based Clipper Saturators

Post by emrr »

mediatechnology wrote: Fri Jun 23, 2023 9:23 am Interesting points.
+1 on the speaker ultimately moving out/pressure wave with positive signal polarity.
If the signal is inverted with greater negative excursion what do you hear change?
Similar to what you hear with flipping polarity on asymmetric sources like vocals or horns, a more present intelligible sound with greater positive excursion, and a more hollowed out less present with negative. Now, they differ in that with vocals and horns we expect to hear it one way versus the other, but it's also true that on occasion a polarity flipped single source percussion track will have more impact in a mix one way versus the other, so a similar effect.

Overall though, these are general comments, and I'm not intending to introduce feature creep, but it if proves easy and useful, why not.

I'd forgotten that drum solo example, pretty wild change there.
Best,

Doug Williams
Electromagnetic Radiation Recorders
User avatar
mediatechnology
Posts: 5473
Joined: Sat Aug 11, 2007 2:34 pm
Location: Oak Cliff, Texas
Contact:

Re: The Waveulator: Two VCA-based Clipper Saturators

Post by mediatechnology »

You're hearing what I do so I guess its not my imagination.

I describe the audibility of absolute polarity on sax this way:
Positive is mellower with more bell, smoother, rounder, more forward.
Negative is more reed, lip, spitty, sucked-in, hollow and honky.
Very technical-sounding. LOL.

I hear polarity on drums as well.
Many years ago I did a LF toneburst test to simulate the impulse of a kick and the differences were large.
Positive was hitting me in the chest and impactful, negative made me hear the first-order echo slap off the hard wall behind me.

By means of simple control polarity reversal odd-order expansive distortion can be made with the Waveulator.
When the input level increases above threshold the gain goes up exponentially.
A little expansion goes a long way.
It creates headroom problems if not managed.

Compressive saturation occurs when magnetics, tape, electronics etc run out of linearity.
We don't have many examples of expansive distortion that occur "in nature."
Two that readily come to mind are magnetic tape without bias and severely under-biased class-B amplifiers.
Not something you hear everyday.

For an effect, expansive distortion is the way to go with the Waveulator.
Instead of adding harmonics that ultimately subtract level from the waveform to make compressive distortion expansive distortion increases the waveform.

Here is a sample of Frank Turner's "Blackout" unprocessed and with some expansive odd-order distortion added.
There are some overs in the processed file.
Since the RMS level increased in the processed file I reduced its' level to be closer to the original.
The transients really pop.

Sound file: https://proaudiodesignforum.com/content ... arison.wav
Image
emrr
Posts: 573
Joined: Sun Mar 02, 2008 10:27 pm
Location: NC, USA
Contact:

Re: The Waveulator: Two VCA-based Clipper Saturators

Post by emrr »

seems useful
Best,

Doug Williams
Electromagnetic Radiation Recorders
TheeAldeen
Posts: 15
Joined: Wed Dec 28, 2022 11:10 pm

Re: The Waveulator: Two VCA-based Clipper Saturators

Post by TheeAldeen »

wayne, will this be another +/-15v module?
User avatar
mediatechnology
Posts: 5473
Joined: Sat Aug 11, 2007 2:34 pm
Location: Oak Cliff, Texas
Contact:

Re: The Waveulator: Two VCA-based Clipper Saturators

Post by mediatechnology »

I think the first one I do will be ±15V powered.

The expansive mode is something I'm cautious about unless used in extreme moderation.
On the first one I do I may make that switchable with a header connection to an optional switch.

Due to appliance and yard entropy it may be a few days before I can get back to the Protoboard.
Post Reply