Contour filter network?

[gearfreak]

I still have (4) x 8256 cabinets, (8 x 3156), so am considering putting them to use again, 2 cabinets per side.

I am thus considering a contour filter to flatten the 'rising response'.

Based on the contour network designer found here:
Contour Network Designer / Calculator

It seems to be that you just setup a low pass filter (coil, in series), then the 'shelving' is tailored by setting the value of the 'bypass' resistor.

So, my question is - is it really shelving at what they are calling 'fm' ?

i.e. will it be flat from 'fm' upwards?

Open to suggestions on other filters, and/or opinions on why such a filter may be a good or bad idea.

thanks!

[Panomaniac]

Yes basically, that's how a shelving filter works.
See below for a 5mH and 8R contour in series with an 8 ohm driver.

The tricky part is that no woofer is an ideal flat line impedance. So you may need to flatten it with a Zobel to get the shelving filter to work the way you want.

[gearfreak]

Excellent, thanks Pano.

(I've doing some re-reading of your xover thread in parallel. ...no pun)

Will have to read up on 1st order low pass before working out the size of inductor needed.

In the end, (particularly per the zobel) it looks like I just have to drag a computer into that room so I can use WT3 to get the response, in their respective cabs...