Window...

[John Mulcahy]

Is there two windows - one to the left and one to the right and one sets the length of these windows in ms?

Yes, there are two half-windows. The pre and post ref windows can be different types and different lengths.

 

[John Mulcahy]

Yes.

 

[John Mulcahy]

I don't know how one might use a window with a gap in the middle.

 

[John Mulcahy]

When analysing the frequency content of an impulse response there is little of interest before the peak, a short window is appropriate there. Post peak the window length will determine the LF limit of the frequency response and the window should be unity over regions where reflections are of interest, a window that tapers from the start would attenuate the reflections and conceal their full effect on the response.

A similar situation arises for the windows used to generate waterfalls, but there the width and shaper of the left window has a strong influence on the appearance of the waterfall (aka the 'rise time' used).

 

[John Mulcahy]

Because the two half windows typically have different shapes, different durations and different effects on the result. How else should that be described?

 

[John Mulcahy]

They are labelled differently in the 5.20.14 builds.