FeedbackLoopDetector

by CharlyBeck

Academic approach. (This device is only for research and has...

Description

Academic approach. (This device is only for research and has no benefit/functionality for users)

This device detects feedback loops in a signal matrix/signal flow graph definition.

How the signal flow matrix works:

Following rules apply for this signal matrix:

- Left side are inputs

- top side are outputs

- In1/Out1 is the main input/output of the device

- The rest of the in/outs are internal routings

- The internal output is connected to the appropriate internal input

- So for n > 1 applies: out[n] is connected to in[n]

- This is why feedback loops may occur if the wrong routing is activated by setting the dot in the matrix.

How i plan to use this:

Later, for each dot in the matrix there will be one "subdevice" which can instanciate a vst plugin.

Using the signal matrix the order and paralel processing of the plugins can be redefined by simply changing the buttons in the matrix.

bpouille · July 07 2020
hi ! do you think this could be used to dynamicaly control the amount of volume being feed in a feedback system so it never goes full larsen, but making a living instrument ? it would be awesome
CharlyBeck · September 25 2020
hi hpoille,
i'm not sure if i understood correctly, but i think the clear answer is: this variant of the algorithm does not deal with audio levels. it just detects feedback loops and provides the disabled state for the matrix controll so a user can not produce such a feedback loop.
the 2nd point is, that i stopped the approach in m4l. instead i created a clr wrapper for coding max externals in c#.
I put a brief description of the project here:
https://karlchenscoderdasein.blogspot.com/2020/05/a-dynamic-signal-flow-graph.html
In the project the feedback loop detection is implemented in c#. This is way simpler than doing it m4l. Aside it didn't work correctly because ableton live has problems if the m4l patch is recursive.