Trace arithmetic question

[dima1stg]

Does trace arithmetic take phase into account?

 

[John Mulcahy]

Yes.

 

[dima1stg]

Then, in theory, graph of A+B should be the same as measuring 2 speakers at once. If this statement is correct, then this is not the case. Please see attached.

 

[John Mulcahy]

To meaningfully compare phase between measurements they must have a common timing reference. You used the left speaker as reference when measuring the left, and the right speaker as reference when measuring the right, so the results do not have a common reference. Pick a speaker to use as the reference and stick to it.

 

[thothsong]

Your L and R measurements have different acoustic timing references (one L, one R). They need to be the same.

 

[dima1stg]

Gotcha!

 

[sm52]

Then, in theory, graph of A+B should be the same as measuring 2 speakers at once.

I checked this specifically on my system. It is so indeed.

 

[serko70]

If I remember correctly, 1/¦A¦ trace arithmetic results didn't have phase response in earlier beta versions but now they do:

 

[John Mulcahy]

If I remember correctly, 1/¦A¦ trace arithmetic results didn't have phase response in earlier beta versions but now they do:

The result has zero phase, though you would probably need to use full width rectangular windows to see a perfectly zero phase trace.