Variable bandwidth?

Hi,
I have had a look through the maul and previous posts but can't find out how to create a bandpass filter with a variable bandwidth. Can anyone help.
Thanks

Lt

 

Use ADSR enveloper to control bandwidth for example

 

just use a lowpass and highpass filter in series with independent cutoff control.

 

Hi,
Yes I thought about using a low and high pass instead, I just presumed that reaktor would have a bandpass with bandwidth control. Anyhow thanks again

Lt

 

You could perhaps do something like the structure in the thumbnail- sorry if this is too obvious to you. Advantage is you have one cut control and a bandwidth control. The disadvantage of this is that you don't have a resonance control for the center frequency of the passband.

Hope this helps...

Nicolaas

 

Hi thanks,
Not too obvious at all. I need the resonance really as it adds to the effect of what I am trying to do. Good to know though.
Thanks again

Lea

 

Why not add an EQ in the middle of that structure, and increase the gain while varying the Q in step with bandwidth, i.e. the frequencies of the HP and LP filters, thus emulating resonance?

The other way you could create resonance is to feedback the output of the the LP filter back in to the HP filter. Controlling the level of the feedback would allow you to control the amount of resonance. Putting a saturator module in the feedback path might not be a bad idea as it would help to keep the gain from the feedback in check.

This is all theoretical. I don't have Reaktor installed on this computer so I haven't tried it, otherwise I'd include a screenshot of the structure.

 

Yeah, i'd been thinking about something like that...

I don't know enough filter theory to do this properly though, but here's a screenshot of the concept. I just put a constant in the resonance and use the gain factor of the EQ as 'resonance', but you could probably get pretty far by trial and error in the resonance-BW relationship to get better results...

Good luck!