Impulse Graph Question

[boxerfan88]

Hello there,

I am trying to make sense about the double spike in the L+R stereo sweep, and understand what it means. Maybe someone out here can help educate me.


Stereo sweep shows a double impulse about 120uS apart...I wonder why? Is it because the L and R speakers are time offset by that amount?

The impulse overlay graph (L-pink; R-red; L+R_green):

The individual speaker sweeps shows only a single impulse (as expected).

Thank you in advance for any feedback about the double impulse.

 

[carsound]

time no alignment​

 

[sm52]

Is it because the L and R speakers are time offset by that amount?

Yes.

 

[boxerfan88]

Thank you very much. Now I understand.

Am I right to assume that 120 uS delay is not a problem?
What's the threshold that one should get worried about?


Researching the web seems to suggest 10ms-20ms (10000uS - 20000uS)...

 

[sm52]

Am I right to assume that 120 uS delay is not a problem?

If there is a delay between the left and right channels relative to the position of the microphone, then this is not a delay, but a different distance from the microphone to the left channel and from the microphone to the right channel. It is not necessary to measure both channels at once.

 

[boxerfan88]

I see. Thank you.