Re: HPF

Thanks for that idea, Chinmay. It's a kludge to be sure, but it solves 
my problem.

I'm still curious as to why the biquad filter node doesn't allow for 
different slope settings as part of the API spec.

Jory

On Mon, 7 Apr 2014 08:26:51 +0800, Chinmay Pendharkar wrote:
> Hi Jory,
> 
> The Biquad topology allows for a filter with two poles and two zeros. Each
> pole gives a 6dB/octave slope. So with 2 poles, biquad can either get 6dB
> or 12dB slope. To get more than 12dB, one can just cascade multiple Biquad
> filters and the slopes add linearly. So 2 BiquadFilterNode in series will
> give you 24dB etc. But you're indeed limited to multiples of 12dB/octave.
> 
> Another way could be to implement a single pole filter using a DelayNode
> and feeding it back through a GainNode. I haven't experimented with that
> yet, but will try it out sometime this week. I believe with a combination
> of the BiquadFilterNode and a Single Pole filter we should be able to get a
> filter with a slope of any power of 6dB/octave.
> 
> -Chinmay
> 
> 
> On Mon, Apr 7, 2014 at 3:46 AM, Jory <me@jory.org> wrote:
> 
>> Hi,
>> 
>> I need to implement a highpass filter with a 24 dB/octave slope, but
>> the Biquad filter node only does 12 dB/oct. I would imagine this
>> shouldn't be hard to do, and perhaps I have to do it with a
>> ScriptProcessorNode, but I also wonder why the Biquad.highpass is fixed
>> at 12 dB/oct, rather than allowing the user to select 6, 12, 18, or 24
>> dB?
>> 
>> Any help on how I can implement this would be greatly appreciated.
>> Thanks!
>> 
>> Jory K. Prum
>> Sound Guy
>> 
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>> 
>> 

Jory K. Prum
Sound Guy

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   -------------------------------------------------------------
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Received on Monday, 7 April 2014 01:46:10 UTC