Instruō Tanh(3)

Hovercraft · Post by **Hovercraft** » Fri May 25, 2018 2:42 pm

Tanh(3) looks interesting, and useful--a waveshaping circuit. This looks useful for controlling feedback loops, limiting/soft clipping, and general waveshaping mayhem.

http://www.instruo.media/tanh3

"tanh[3] is a three channel, all analogue, wave shaper. It takes an input signal and outputs the hyperbolic tangent function [tanh (x)] for that signal.

…In more useful terms, it adds curves to a signal!

Traditionally the circuit is used to shape a triangle wave to a sine but when used with more complex signals it behaves as a single knob limiter."

Crimesofthecrown · Post by **Crimesofthecrown** » Fri May 25, 2018 3:20 pm

Ooooooooooo. I like this.

windspirit · Post by **windspirit** » Fri May 25, 2018 3:22 pm

Yeah just saw this in the most recent divkid video, seems like a really useful utility.

mgscheue · Post by **mgscheue** » Fri May 25, 2018 4:19 pm

Interesting. I just tried plotting what it would do to a triangle wave. Something like this, it appears.

windspirit · Post by **windspirit** » Fri May 25, 2018 4:26 pm

I am not familiar with that way of computing a triangle wave, but around 0 for half a period you should see the triangle wave basically act like a linear input which would mean that you should see something more like the graph on the panel of tanh(3).

AFAIK the normal equation for a triangle wave is sin(x) + 1/3 sin (3x) + 1/5 sin (5x). Correct me if I am wrong.

Here is a graph of tanh for reference

mgscheue · Post by **mgscheue** » Fri May 25, 2018 4:41 pm

Admittedly, I haven't seen this stuff in a while, but I think what you have there is the first three terms of the Fourier series for a square wave:

They're similar in that they both have just the odd harmonics.

You can of course represent a triangle wave as a Fourier series, too, but what I have as the argument to tanh should be the analytic form.

Hovercraft · Post by **Hovercraft** » Fri May 25, 2018 5:08 pm

My understanding is the circuit can fully shape a triangle wave into a reasonably pure sine wave. Maybe there’s more to the circuit, but Jason specifically refers to MAX/MSP and Pd users. Seems like it would be a basic function. From the description on the web site—

Wave shaping:

Running a triangle wave through a tanh will allow for some interesting wave shaping control.

Fully CCW and the resulting signal will be a slightly attenuated pass through of the original triangle wave. As the level is increased, the corners will soften and the wave form will shape into a sine wave.

As level is increased, the sine will soft clip and eventually settle into a unique peaked waveform.

mgscheue · Post by **mgscheue** » Fri May 25, 2018 5:19 pm

Yeah, that's what actually made me curious about seeing what happens if you feed a triangle wave to the tanh function. It definitely rounds it some, but it's still pretty pointy on the top and bottom. It would be interesting to try it, with a scope, with the actual module. Sounds like the control makes it "stronger" than just a straight-up tanh would. I remember looking at the sine output of my STO, which is a triangle-core oscillator, on my scope, and while it was quite close to a sine wave, it was just a little pointier than that.

windspirit · Post by **windspirit** » Fri May 25, 2018 5:54 pm

https://en.wikipedia.org/wiki/Triangle_wave

Looks like it is actually an infinite series of the odd harmonics but with decreasing amplitude (inverse of the harmonic number).

You might try amplifying the triangle wave (multiply it by 10 for example) before going into the tanh function.

tapel · Post by **tapel** » Fri May 25, 2018 6:18 pm

I’m a long time user of tanh~ in Max and Pd for controlling and manipulating feedback. I bought a tanh[3] and am having a good time using it in feedback loops with the DLD (with the Send-Return-Pre-Loop alternative firmware). I am finding that I also am using it for boosting signal levels in general, like for the filtered outputs from the Benjolin. Just like in Max, for me it’s a convenient way of controlling signals that might get out of control.

AndreasD · Post by **AndreasD** » Fri May 25, 2018 6:54 pm

In the software world tanh is used to simulate/create saturation and distortion. It's also a limiter, but with heavy distortion (clipping) when limiting.
Tanh creates odd harmonics only, no even harmonics.

Brennanib · Post by **Brennanib** » Fri May 25, 2018 10:56 pm

Ordered on of these from Jason recently can't wait for this honestly I've been needing something like this for some time now and yet they're are others this one does just what I need and more in a 4hp package!!

starthief · Post by **starthief** » Tue May 29, 2018 8:07 am

tapel wrote:I’m a long time user of tanh~ in Max and Pd for controlling and manipulating feedback. I bought a tanh[3] and am having a good time using it in feedback loops with the DLD (with the Send-Return-Pre-Loop alternative firmware). I am finding that I also am using it for boosting signal levels in general, like for the filtered outputs from the Benjolin. Just like in Max, for me it’s a convenient way of controlling signals that might get out of control.

I'm interested in it specifically for taming feedback, but it seems kind of limited (ha) in control possibilities compared to using an envelope follower and VCA or a dedicated compressor.

In practice, do you ever find yourself wishing for more control of it, or is it just a matter of pushing the levels a little more or less and it takes care of itself?

peripatitis · Post by **peripatitis** » Tue May 29, 2018 10:01 am

Very useful module, it just needs a better delay line to shine..

bgribble · Post by **bgribble** » Tue May 29, 2018 1:21 pm

In the software world tanh is used to simulate/create saturation and distortion.

Funny, right? tanh distortion is used in software as a quick and dirty mathematical approximation to "euphonic" hardware limiting/distortion, and now we have a hardware implementation of the algorithm that was a knockoff of the behavior of tubes-and-transformers hardware....

bg[/quote]

ookrsia · Post by **ookrsia** » Wed Jun 27, 2018 12:37 pm

Wow gotta check this. I love using feedback but it can sometimes be tricky.

With this price and HP it seems a no-brainer.

timoka · Post by **timoka** » Wed Jun 27, 2018 2:03 pm

such a useful module, one of the best purchases i made since a long time!
nothing musical here, just to demonstrate the saturation, clipping on a sine wave and the feedback control in a delay:

http://soundcloud.com/uzala/tanh3-sinewave

http://soundcloud.com/uzala/tanh3-feedback

Hovercraft · Post by **Hovercraft** » Wed Jun 27, 2018 5:23 pm

Nice examples. I'm enjoying my tanh(3)--such a cool module. It's also great for waveshaping--I like multing an osc and running one line into tanh(3) and layering it with the original sound.

djd_oz · Post by **djd_oz** » Wed Jun 27, 2018 6:15 pm

windspirit wrote:Yeah just saw this in the most recent divkid video, seems like a really useful utility.

where is this video you speak of, can't seem to find it

Swain Voorman · Post by **Swain Voorman** » Thu Jun 28, 2018 7:54 am

Might be here:
https://youtu.be/XB5c3D-rWtY?t=31m47s

Interested to see DivKid's video on it in the future. I'm very interested in the potential for this one with my setup being based around acoustic sound input and delay lines. Thanks everyone for the demos thus far.

ben_hex · Post by **ben_hex** » Thu Jun 28, 2018 8:26 am

Swain Voorman thanks for sharing the live stream I did with Jason, was fun to get into that module as I think it's a very useful little thing in 4hp.

No plans for doing the demo particularly soon, need to get through some other things first and Harmonaig is next in line for Instruo videos from me.

brandonlogic · Post by **brandonlogic** » Tue Aug 07, 2018 8:08 am

mgscheue wrote:It would be interesting to try it, with a scope, with the actual module.

i would love to see some oscilloscope shots with the actual module too.
could anyone with the module show us what it looks like processing a sine, triangle and saw? thanks in advanced!!

timoka · Post by **timoka** » Tue Aug 07, 2018 9:11 am

here are some pictures to show what it does to waves:

sinewave:

trianglewave:

sawwave:

and here the audiofile:

http://soundcloud.com/uzala/tanh3-waveforms

brandonlogic · Post by **brandonlogic** » Tue Aug 07, 2018 9:15 am

Awesome thank you so much timoka, really appreciate it! I think im going to pick one up. would be really nice with the DLD's feedback loop too, because its really easy to get out of control.

mgscheue · Post by **mgscheue** » Tue Aug 07, 2018 9:21 am

Yes, thank you! Very interesting.

MUFF WIGGLER

MUFF WIGGLER

Instruō Tanh(3)

Instruō Tanh(3)