Help with step response

[boxerfan88]

Dear all, I would be grateful if someone can shed some light why a step response so called "starting point" or "zero point" can be so far below zero.

Refer to the attached image.

Any feedback would be appreciated. Thank you very much.

 

[jtalden]

The tweeter sound arrival is delayed about 12 ms relative to the subwoofer. This is not the conventional timing arrangement, but it is not necessarily a bad one for SPL and sound quality. A lot more information would be needed to tell. Some favorable delay timings have a step response similar to this. The step response itself is not a very good indicator of anything beyond this simple observation. Choose the delay timing that has favorable SPL response in the XO range and sounds the best to you.

 

[boxerfan88]

Okay, so the vertical axis isn't that important I guess, since the peak is locked to 100%, everything else is scaled/displayed relative to the 100% peak.

 

[boxerfan88]

I redid the measurements, keeping everything constant except for subwoofer delays.
The main speaker is a 3-way active, and single subwoofer.

The chart looks like this:

^ the red one has subwoofer delay of 5ms added in the digital crossover configuration.

I have marked out the various peaks to the various drivers ... is that the correct way to interpret the timing of each driver in the step response chart?

 

[boxerfan88]

What is a reasonable time delay between woofer vs. subwoofer?

 

[jtalden]

I have marked out the various peaks to the various drivers ... is that the correct way to interpret the timing of each driver in the step response chart?

The TW and SW are probably correctly identified as to the peak of their respective impulses. I have low confidence that the same is true for the W and Mid. The step response is not a good way to make any delay decisions however. There is no reliable way to infer the relative phase response and resulting frequency response from it.

What is a reasonable time delay between woofer vs. subwoofer?

The REW Alignment Tool is an excellent tool for driver delay timing. There are numerous YouTube videos and AVnirvana threads here for guidance.

 

[boxerfan88]

Thank you very much for sharing your insights. Much appreciated.

 

[RahulKuhic]

The TW and SW are probably correctly identified as to the peak of their respective impulses. I have low confidence that the same is true for the W and Mid. The step response is not a good way to make any delay decisions however. There is no reliable way to infer the relative phase response and resulting frequency response from it.


The REW Alignment Tool is an excellent tool for driver delay timing. There are numerous YouTube videos and AVnirvana threads here for guidance.

I learned a lot here, I was about to raise questions against the same but now it seems the problem is solved.