Is it possible to modulate the ModeAmps of the ModalFilter?

Question

Hi there,

I've got some nice physical models using the ModalFilter already but now I thought it could be interesting to modulate the ModeAmps. The problem is they only seem to update when I reset the ModalFilter. Why is that?

I'm not really using the feedbackLoop but rather worked with the Bandwidths so far so I thought I could work around using replicated AllPassFilters maybe. Just want to make sure it's worth the effort..

Thanks!

Answer 1

Just tried a test, and ModeAmps appear to be continuously updating here.  If you have an example that you think might not be working, could you please email it to us?

Thanks!

Comments

Here it is:

ModalFilter not updating ModeAmps example

If you send a KeyDown and hit the trigger to distribute new random ModeAmps while the filters are ringing you can clearly hear that they are not updated. If you send another KeyDown the filter resets and the ModeAmps are updated.

Thanks!

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The ModalFilter is working correctly. It is a physical model where the modes emulate the modes or resonances of an object and the input is an excitation (such as striking a metal bar or plucking a string). The ModeAmps control how much the excitation excites each mode.

In this model, each ModeAmp is applied to the input (not the output) of its mode filter. Since your input dies away very quickly, you are hearing the impulse response to that input. However, since the ModeAmps affect only the inputs to the filters, once your input dies away, you will no longer hear the effect of changing the ModeAmps.

With a constant or longer duration input, you do hear the changing ModeAmps.

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Got it, thanks for making this clear!