Tie fighter: Vented or compound?

Hi all,
I was playing for some month into this plan. It's a 1x15" rear loaded horn with a front extension I developed some versions of this extension and I want to know other members' opinion. The lrc's vented version is equal to the all horn length's compound version, 15 cm. External dimension is 83.6x60x53.6. So 3 of this cab can sit perfectly on 4 scoop.
Vented version:
vrc=38 litres
ap=1260
lpt=2

16x16 Compound version:
front horn throat=1600 cm^2
front horn mouth=1600 cm^2

16x20 Compound version:
front horn throat=1600 cm^2
front horn mouth=2000 cm^2

20x20 Compound version:
front horn throat=2000 cm^2
front horn mouth=2000 cm^2

22x16 Compound version:
front horn throat=2200 cm^2
front horn mouth=1600 cm^2

20x16 Compound version:
front horn throat=2000 cm^2
front horn mouth=1600 cm^2

22x20 Compound version:
front horn throat=2200 cm^2
front horn mouth=2000 cm^2

And...all the spl plots in one graph (combined response of course)


so what it is the better in you opion and why?
cheers, bitzo

kinda looks like all of them will honk at around 230 hz to varying degrees. what frequency range are you wanting this cab to play ?

80 hz to 200 hz but... I've many doubts about the best configuration a flatter response with more extension or an higher response but more peaky?

@Dangernoise

See the scale - it's not as much of a peak as it seems.

Bitzo, looking good.

I usually pick the flatter ones, but the best thing to do would be to pick a prototype and swap things around while measuring.

Did you read the Dinsdale horn articles? They've got a good bit on double horns...though I suspect this is more like a RLH/REflex that has an odd cancellation frequency due to the recess and subsequent delay from the front of the cone.

thanks for your reply Deadbeat, before prototyping I want to calculate all the possible problem and issue around this cab.
Do you mean the dinsdale articles on volvotreter site?

I'm just trying to calculate the delay...so...
the rear loaded horn have a length of 87 cm
the front loaded horn have a length of 15 cm
so 0.87 m/321 m/s-0.15/321 m/s=2.2243 millisec of delay
am I right?
is there a method to calculate what frequencies are attenuated by the phase cancellation?

cheers, bitzo

I make a typo in my sims...the rear loaded horn is 10 cm longer....
resimmed all the solution and reposted the plot...

NOTE: don't sim at 3 a.m. smiley2