Filter import from Rephase

[Breeman]

Hi,

Just a quick question. I am trying to import a filter generated in Rephase into REW as an impulse but I am getting wiggles in the phase response at low frequencies. Any pointers as to what is causing these and how should get rid of them?
Here is the LR-24 db/oct, 1 kHz HPF filter response in REW;

The Rephase screenshot from where the filter was generated from;

I have also noticed that when trying to generate the minimum phase response of this filter from within REW, its response deviates significantly from an ideal minimum phase response of this filter at low frequencies.

Here is my Preferences screen,

 

[John Mulcahy]

It would be easier to comment if you attached the impulse you are importing, but since that region corresponds to an area where the magnitude of the response is very low it is probably due to the response falling into the noise floor. It may even out a little if you widen the IR window, but dynamic range is the more likely limitation.

 

[Breeman]

It would be easier to comment if you attached the impulse you are importing, but since that region corresponds to an area where the magnitude of the response is very low it is probably due to the response falling into the noise floor. It may even out a little if you widen the IR window, but dynamic range is the more likely limitation.

Thanks for a quick reply, here is the attachment.

 

[Breeman]

Any thoughts on the REW generated minimum phase not in alignment with the ideal minimum phase of this filter?

 

[John Mulcahy]

As above, the response runs into dynamic range limitations. The min phase plot is of the actual response, including its noise floor, not what it would theoretically look like if dynamic range were unlimited. A longer export might be a little cleaner.

 

[Breeman]

Thanks, it makes sense.