Setting to disable automatic determination of Ref in IR plots

[p-we]

Hello REW forum,

New REW migrant in loudspeaker design here. I noticed that the Ref point is automatically matched to the time of the IR peak at each new measurement. While I have seen that the windows of L and R relative to Ref can be manually overridden, I have not found a UI control to disable the automatic setting of Ref at each new data capture so I don't think it is there. If a bypass for this does exist, please advise how to do it or perhaps explain a simple workaround.

I understand why this feature is important, however there are specific scenarios where it is desirable for a new data capture to keep all parameters, including IR timing points, unchanged from the previous measurement.

Thanks,
Wes

 

[John Mulcahy]

There is an button on the IR windows dialog to apply the current window settings to all measurements. The window ref is less important than the t=0 position, for a consistent t=0 position between measurements use a timing reference.

 

[p-we]

There is an button on the IR windows dialog to apply the current window settings to all measurements. The window ref is less important than the t=0 position, for a consistent t=0 position between measurements use a timing reference.

Thanks for the explanation. So that functionality is there essentially as a post-process feature. Brilliant.

I'll have to experiment with this. I am wondering if the "Generate minimum phase" command was applied to a particular SPL measurement to achieve minimum phase for that dataset, and then the "Apply the current window settings to all measurements" was used, would the exact amount of phase shift be applied to the other measurements thereby keeping their relative phase differentials preserved?

 

[dcibel]

It's important to note that REW is a bit "weird" in that the phase for a given measurement is always shown with respect to t=0, not the window reference location. A loopback timing reference is the best way to ensure t=0 remains constant for all measurements, and a timing offset when measuring can be used to ensure that the impulse occurs near t=0 in the measurement so the phase is more easily viewed.

 

[John Mulcahy]

I am wondering if the "Generate minimum phase" command was applied to a particular SPL measurement to achieve minimum phase for that dataset, and then the "Apply the current window settings to all measurements" was used, would the exact amount of phase shift be applied to the other measurements thereby keeping their relative phase differentials preserved?

Definitely not. Generating minimum phase throws away the phase information from the original measurement.