What is the effect of Baffle Step on the Phase?

[Bricolo]

Hi all,

Here's a question that just came to my mind.
We all know that the baffle step effect reduces the amplitude of the acoustical for the frequencies below the baffle width.

That can be compensated for, actively or passively.

But if the Baffle Step lowers the signal by 6dB in the lows, how is the phase affected? I haven't seen any information about that.

Cheers,
Alex

 

[phase_accurate]

The behaviour of the baffle-step is minimum-phase. Beacuse of that it has the same phase-response as a so called lead filter. The ususal lag filter that is used to EQ it has a phase and amplitude response that is the mirror image of the lead filter.

Regards

Charles

 

[Bricolo]

Good news.

Is there any non-minimum phase behaviors in "natural" things anyway? (by natural I mean physical effects you can observe, not a filter function created by humans)

 

[sreten]

Hi,

The phase is affected the inverse of the correcting circuit.
i.e. : BSC puts the theorectical phase back where it should be.

/sreten.

 

[Svante]

Hi,

The phase is affected the inverse of the correcting circuit.
i.e. : BSC puts the theorectical phase back where it should be.

/sreten.

Yes, indeed.

A simulated case can look like this. It can be seen that the baffle step (green curve) has a positive phase shift around 300 Hz, and that the compensation circuit has a negative phase shift of approximately the same magnitude. This results in the red curve, which is near zero.

An externally hosted image should be here but it was not working when we last tested it.