Masa

Having a poor math background, I understood that tanh-driven distortion theoretically clips audio signal slightly 'harder' than atan-driven distortion. Is my understanding correct?

I came to that understanding by looking at the graph of this pdf.

https://ccrma.stanford.edu/~dtyeh/papers/yeh07_dafx_distortion.pdf

Having a poor math background, I understood that tanh-driven distortion theoretically clips audio signal slightly 'harder' than atan-driven distortion. Is my understanding correct?
I came to that understanding by looking at the graph of this pdf.
https://ccrma.stanford.edu/~dtyeh/papers/yeh07_dafx_distortion.pdf


atan-distortion-vs-tanh-distortion

this is Max, why not test it for yourself? 

Thank you very much for your nice patch. I posted this because I wanted to understand this from a theoretical aspect as well as a practical aspect for my knowledge.

Thanks to your patch, I can confirm that there is slightly more distortion with tanh~ than with atan~, but the difference is very little.

Thank you very much for your nice patch. I posted this because I wanted to understand this from a theoretical aspect as well as a practical aspect for my knowledge.
Thanks to your patch,  I can confirm that there is slightly more distortion with tanh~ than with atan~, but the difference is very little.


tanh has become the "how you do it" method because it is very CPU friendly.

I didn't know that it's CPU friendly. Thank a lot!

I'm afraid I'm not sure what you mean with "how you do it" method though.

I didn't know that it's CPU friendly. Thank a lot!
I'm afraid I'm not sure what you mean with "how you do it" method though.


er, tanh is *** not *** cpu friendly. no msp trig is cpu friendly. that's why we look for approximations.

Ah it's not? Could you kindly tell me a bit more about 'approximations'?

i actually referred to tanh versus atan, and he is right indeed: tanh requires 2x time more the processing power.

yet both of them are very cheap compared to traditional "professional" methods such as deconvolution and/or FIR based processes.

what works very well with tanh is to use it in a dynamic model. you can do *pi, tanh, or you can only process values outside of -0.5 and 0.5 with tanh, so that only louder levels are affected. this way you only need 2 additional + and * msp objects to have a dynamic curve which the user can adjust to his liking.

>yet both of them are very cheap compared to traditional "professional" methods such as deconvolution and/or FIR based processes.

I don't know how to interpret such professional methods in Max, but it's good the tanh method is cheaper for CPU.

>what works very well with tanh is to use it in a dynamic model. you can do *pi, tanh, or you can only process values outside of -0.5 and 0.5 with tanh, so that only louder levels are affected. this way you only need 2 additional + and * msp objects to have a dynamic curve which the user can adjust to his liking.

>yet both of them are very cheap compared to traditional "professional" methods such as deconvolution and/or FIR based processes.
I don't know how to interpret such professional methods in Max, but it's good the tanh method is cheaper for CPU.

>what works very well with tanh is to use it in a dynamic model. you can do *pi, tanh, or you can only process values outside of -0.5 and 0.5 with tanh, so that only louder levels are affected. this way you only need 2 additional + and * msp objects to have a dynamic curve which the user can adjust to his liking.
That additional tip is great. Thank you!


atan distortion vs. tanh distortion