Using REW to setup B&K PEQ and notch filter

[Jarrod]

I watched Transformers this morning and decided I wanted more infrasonics. So I spent several hours tweaking the shelf, notch and crossover filters, as well as the relative gain on the two subs to achieve that, as well as an even smoother response. New settings are +6dB below 40Hz for the shelf, -9dB at 62Hz for the notch, and a crossover of 60Hz.

Here is the response with the mains playing:


----------------
And here it is for subs only:

[Wayne A. Pflughaupt]

Jarrod wrote:

I do not know what the drop out at 111Hz is about - this appears any time I engage the notch filter, and seems to be independent of the location or amount of correction applied. Strange, but it doesn't seem to be audible.

Maybe a phase interaction between the filter and your crossover? If there is a phase or distance adjustment on your crossover, that might help. Fortunately, deep and narrow notches like that are often inaudible...

Regards,
Wayne

[JimP]

What are you doing to time align everything.

[Jarrod]

What are you doing to time align everything.

Other than making sure that speaker distances are accurate in my processor (impossible for two subs), I haven't even considered it at this point.

What should I be doing? Here is a waterfall plot of the setup as it sits currently:

[Jarrod]

Wayne A. Pflughaupt wrote:

Maybe a phase interaction between the filter and your crossover? If there is a phase or distance adjustment on your crossover, that might help. Fortunately, deep and narrow notches like that are often inaudible...

I don't know, Wayne. My processor has no such adjustment and this goes beyond my basic, qualitative understanding of how a crossover works.

The more plots I do, the more I think this dip at around 100Hz be a real cancellation effect. I'm not sure why it seemed to be correlated with the notch filter when I first noticed it (doesn't seem to be now), but if it indeed is related to the filter then whatever detrimental effect this may represent is more than offset by the benefit I'm getting from engaging the filter.