A two way speaker using the SEAS CA18RNX and Vifa D27TG-05 drive units.

This design is a two way.  Here is the box alignment for the woofer.

Note that the driver and port will displace 0.0408 cu.ft. in the enclosure, this will have to be added to Vb.  To get to Vt you will have to add brace volumes as well.  Mineral wool (Rockwool) should be placed on the back surface behind the driver.  50% of the internal surfaces should be covered with Polyfill.  Damping is included in Vb.

This is the crossover.  Chokes should be air core. L1L2.  The value is 1.5 mh, but this is close enough to 1.6 mh.

C1 and C2Ce.

Rp1Rp2Req.

The rise below 1 kHz is intentional to correct the diffraction loss of the cabinet.  The acoustic response is for a driver on a baffle, so when loaded the rise will continue to cut off as intended.  These Vifa tweeters have a slight rise in response at 15 kHz but there is no need to notch it.

The crossover point is at 2.8 khz and both drivers are down 21 db an octave either side of crossover.  The tweeter has an Fs of 1500 kHz and ideally the tweeter should be a little further down at that point, but I think the result will be satisfactory.  This could really only be corrected by selecting a tweeter with a lower Fs.

With the diffraction compensation these speakers have to be considered essentially five ohm.  The phase response is superior and the speakers are only 90 degrees out of phase at crossover.

When the boards are constructed the inductors should be spaced from each other as far as possible and their axes at 90 degrees to one another.

This is the port you will need, you will have to cut to length.

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