RE: Input and Biquad/QuadBiquad.h and Source...

silver2row am I allowed to use more than one boot setup class in the source?

you can only have one setup() function in a project.

silver2row I looked up the math_neon.h file and there is nothing in it on the docs. Is that on purpose?

there is not much to know about it. It contains fast implementations of some of the math functions available in the standard C library. See, e.g.: https://github.com/BelaPlatform/Bela/wiki/Fast-math-functions, or The Source https://github.com/giuliomoro/math-neon.

silver2row Anyway, do I need to make the bool class in .cpp file aware of my interactions/source within render?

I have no idea what this means.

The full file would look like this:

#include <Bela.h>
#include <libraries/math_neon/math_neon.h>

bool setup(BelaContext *context, void *userData)
{
	return true;
}

void render(BelaContext *context, void *userData)
{
	for(unsigned int n = 0; n < context->audioFrames; ++n)
	{
		for(unsigned int c = 0; c < context->audioInChannels && c < context->audioOutChannels; ++c)
		{
			float gain = 1;
			float in = audioRead(context, n, c);
			float out =  tanhf_neon(in * gain); // using tanh for distortion. Experiment with other functions here
			audioWrite(context, n, c, out);
		}
	}
}

void cleanup(BelaContext *context, void *userData)
{}

I'm curious if you want distortion or a filter sound? Or maybe some of both?

To be clear on terms, "distortion" is usually taken to mean a mathematically nonlinear function that creates harmonics that aren't naturally in the source material.

A filter can selectively make certain frequency components more or less audible (like filterbanks or audio EQ).

Modulated filters can create a form of distortion (like frequency shifting) but we don't often call it distortion since this term is often reserved primarily for waveshaping functions.

Maybe some more explanation for what type of effect you want to perform on the violin somebody can give some specific help. Perhaps the Biquad is the thing you want and you only need some ideas to make this change the sound of the violin in a way you can easily hear.

Maybe you want some distortion like suggested by @giuliomoro where you clip the signal and make it sound more like electric guitar.

For example, I have coded a variety of sound effects which can be implemented on Bela that somebody could use for many fun experiments with a violin. These aren't simple enough for me to recommend them as examples for learning how to use Bela. The examples provided by the Bela team are better for learning because they are short and focus on one thing at a time.

https://github.com/transmogrifox/transmogriFX_bela

Everything works as-is, but you need to have something connected to the Analog Inputs to adjust levels or you might get settings stuck in very strange positions...and you need switches on digital inputs.

as far as i get it, you want to have this violin open to the public, or at least have it played by people who don't normally play the violin? nice.
so i understand that you would prefer some sort of 'different', 'unexpected' or 'surprising' sound to come out of the speaker, instead of just a badly played violin. hah.

and while trying out all the examples may be a good starting point, i have to agree with @[deleted] and @[deleted] that this conversation would become easier once you decide what you want to do with the sound to make it surprising.
you could have distortion, but only on the lower notes. you could have the higher notes be chopped up with a tremolo and disappear into an echo. or maybe you want to trigger Winston Churchill speech samples and speed them up as the violin gets louder?

people here are more than willing to help you get the results you want - but it's kind of hard to help you if you don't know what you want to achieve.

(that said, i can only help you if you choose to go with Pd - my C++ is still at kindergarten level.)

silver2row Enjoy the Faire!

ryjobil quick review of the code shows it starts in an active state

i was under the impression that the default was 'bypass = true'.
i should think that it therefore starts in bypass?

Remork i was under the impression that the default was 'bypass = true'.
i should think that it therefore starts in bypass?

While it is true that make_klingon(...) will create a Klingon Tone initialized to bypass state, the specific sketch referenced sets it to active state when you start the sketch.

See render.cpp, in function setup(...)

    //Bypass is the least intuitive function:
    // If second argument is true, it forces bypass state.
    // If second argument is false, it toggles bypass state.
    // The second call below is all that is needed after make_klingon(), since the constructor function
    // sets bypass state to true.  A call to kot_set_bypass(kot, false) would then toggle to active-state
    // since it is already initialized to bypass state (true).
    // However for clarity in the example it is explicitly set to true, then toggled to demonstrate the normal sequence when
    // the current bypass state is unknown.
    kot_set_bypass(kot, true);
    kot_set_bypass(kot, false);

Notice I fixed the comment here, but haven't pushed a fix to the comment in the code, so you will see a discrepancy if you read this section of the code before I get around to fixing it.

It seems like the difficulty you are facing is related to getting started with Bela, understanding the way it is designed to be used. If my guess is correct, then below might help you get the code running.

This first statement is to describe the assumption I am making about which Zip file you are talking about. The way to get a Zip file from the github repository I sent in a link is like this,
https://github.com/transmogrifox/Bela_Misc
,then there will be an option "Code" and "Download Zip".

Is that the Zip file to which you have made reference?

If this is what you mean, then you may unzip this zip file you will have a directory structure of the repository, which looks like the corresponding github page -- within there are multiple directories each having a different sketch. Each one is its own Bela project and I am uncertain what Bela would do with the whole of Bela_Misc copied to a single project directory.

You need a new project that includes all the .cpp, .h and .txt files you see here:
https://github.com/transmogrifox/Bela_Misc/tree/master/klingon_tone

This means on our PC you would browse to the kingon_tone directory under the unzipped Bela_Misc directory and upload those files to a new project from the Bela IDE, like below.

1) Download Bela_Misc repository zip from https://github.com/transmogrifox/Bela_Misc
2) Extract zip to your PC
3) Open web browser to Bela IDE -> create new project, name it whatever you want
4) Delete the default (auto-generated) render.cpp
5) Use menu option to upload project files
6) Browse to extracted zip directory, klingon_tone
7) Upload all .cpp, .h, .txt files from directory klingon_tone to this new project directory
8) Build and run
9) If 8 works, then you can modify code using the IDE editor to observe how it may change the sound, and/or adjust project settings in the IDE (e.g AGC gain, DAC gain). Defaults will be ok for testing basic compilation and verify sound has changed.

If you have more experience with Bela, there are more elegant ways you can learn to copy the code to the correct place The above method is one way that is easy to explain, and it works.