Can anyone model this PPSL in Hornresp for me?

[DaveFred]

I have no idea how to use Hornresp.

I want to build a PPSL sub using two of these drivers,

Parameters,
Fs 21.3 hz
Senstitivity 87.2 @ 2.83V/1M
Mms 275.9 g
BL 18.4 N/A
Cms 0.276 mm/N
Vas 67.5 L
Qms 3.962
Qes 0.414
Qts 0.374
Nom Imp 4 ohm
Re 3.7 ohm
Le 1.38 mH
Xmax 28 MM
Sd 491 cm^2

Dimensions,
Outside Diameter 312 mm
Cutout Diameter 277 mm
Depth 225 mm

I have attached a picture of my sub drawing,

The throat opening is 9" high by 13.25" wide by 14" deep.

From what I have read about PPSL subs, the front port size is supposed to be equal to the SD of one of the drivers, which in this case is 491cm^2. The only way to front load the drivers is if the port is 769cm^2, which is about 56% too big. How badly does this impact the output?

Any info I am missing for some kind soul to help me?

Or am I out to lunch?

 

[weltersys]

1) How badly does this impact the output?

2)Any info I am missing for some kind soul to help me?

3)Or am I out to lunch?

1) The volume and depth of the plenum will impact the output level and frequency of the "pipe resonance" it causes in the upper range of the output. The plenum volume and depth will have virtually no effect on the LF output, other than the reduction of the net box volume used for low frequency reduction.
2) The volume displaced by the driver is missing, (.2 cubic feet IIRC) important information for small boxes and plenums.
Measurements of the dust cap and distance from it to the cone surround centerline are needed to use the Hornresp cone volume estimator. You can measure the cone volume "for real" using some plastic wrap over the cone and fill with water (or rice or macaroni) and then pour it in a measuring cup.
3) As in missing an important detail?

With 28mm Xmax, the suspension and vent noise may be more objectionable than than even order harmonic distortion that is reduced by push-pull mounting.

Worth an open-air listen before committing to a design.

Cheers,
Art