Changing High-pass Q - Not Working

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Dave Ernst
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Last seen: 2 months 3 weeks ago
Joined: 03/15/2017 - 2:13pm
Changing High-pass Q - Not Working

Hi,

I'm using a second order butterworth high-pass filter within a Second Order Filter Cascade. I would like to increase the Q of the filter but changing the value does not appear to actually change anything.

I'm using AWE Standard 6.17.05 at the moment.

I appreciate your advice. Thanks!

Axel Nilsson
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Last seen: 1 day 21 hours ago
Joined: 12/19/2016 - 2:02pm

Hi Dave,

 

By definition, a Butterworth filter has a constant Q of 1/sqrt(2) (~.707). This means that in the inspector of the Second Order Filter Cascade module, the Q factor is actually decoupled from the module when the filter type is Butterworth. 

 

If you want to change the Q factor for a second order HPF, there is the VariableQHPF choice at the bottom of the filterType dropdown list that will meet your needs. You'll see that if you set the Q to .707 with this filterType, you'll have the same frequency response as your Butterworth filter. 

 

Hope this helps you out,

Thanks

-Axel

Dave Ernst
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Last seen: 2 months 3 weeks ago
Joined: 03/15/2017 - 2:13pm

Hi Axel,

Thanks for the support.

I realized that the VariableQHPF was not an option in AWE 6.17.05 but it is in the latest version. I'll try it out.