"All Phase"

[bobolix]

For some purposes, it would be advantageous to be able to display multiple phase responses simultaneously (analogous to All SPL) and their average value, as well as to export the average characteristic including phase information.

 

[John Mulcahy]

Vector average includes phase. The Phase Overlay graph shows all phase responses.

 

[bobolix]

Thanks and apologizing, I somehow missed it. REW rulez !

 

[bobolix]

Nevertheless, it seems some kind of smoothing applies at the vector averaging. Is it true ?

 

[bobolix]

Note nothing similar exists at RMS avg.

 

[bobolix]

I have another problem with the averaging. Attached are two pictures related to two tweeters averaging, the first beeing created by RMS avg, the second by vector avg. There must be something wrong with the vector averaging definitely, but absolutely I can't get what. Both graphs were creates under the same conditions as these in the my previous comments, which have been related to six woofers.

 

[John Mulcahy]

Images aren't very useful for investigation, please attach the measurements.

 

[bobolix]

They are here:

 

[John Mulcahy]

The problem with your tweeter measurements is you set the left window to zero. Why did you do that? Here they are with 1 ms left window (or you could just set some suitably non-zero left window width on the result).

There is no smoothing in vector averaging, though the averaging may reduce random variations.

 

[bobolix]

I tried to reproduce the smoothing effect for the six woofer, without success, all seems to be O.K. . Now I'm really confused. .

 

[John Mulcahy]

I am now also confused, did you read my reply? There is nothing wrong with the vector average of those tweeter measurements, the only problem is your window choices.

 

[bobolix]

Concerning the left window zero - it was not set in fact. At the original measurements there was the Left window zero without problems and it was left for averaging, too. (Usually I adapt the left window so that the correct phase response were achieved - a problem with the noise or so.) The matter of fact is that if the vector average is made, then the reference point (Window Ref Time) is automatically set to the peak sample of the resulting impulse response (0.038 ms in the examined case), and if the Left Window is set to zero, then the result is wrong, because a part of the impulse is lost for the frequency response calculation. If the Ref Time is set to zero manually, then all is O.K. even if the Left window is zero still.

Now it is all clear for me, but I think it would be better maybe if the Window Ref Time was not changed at the vector averaging. However there could exist another problem perhaps, what Ref Time should be used if these for different original responses were different. It seems at the existing state the first peak sample is chosen.

 

[bobolix]

BTW, i presume the vector averaging is performed rather on the impulse responses than on the complex frequency resposes - isn't it ?

 

[John Mulcahy]

Trace Arithmetic operations are done in the frequency domain using data obtained from applying the windows that have been set for the responses.