ok i think im ganna make the 18" WO.....now i have to think about porting the back chamber ???...why can i just let good enuff b just that....... *light comes on* i am a bass freak....thats why

This has come up a million times. The WO is a 4th order bandpass with what is similar to a multi port front side.
If you wanted to model it, my best guess would be to model it as a 6th order and find software that lets you put multiple ports of different sizes in the front chamber and then add a port to the rear chamber. I tried several times, but could not get anything reliabole from the computer model. The best we did was experiment with a hole in the mouth of the horn and adjusting it's size. If you leave it the length of the peice of wood (3/4") the size of the hole will determine the tuning frequency, but beware the box becomes very one note oriented.
I have not tried extending the port to make it an actual tuning element, but I think it would have some effect. If it could be tuned close to the same as the mouth of the front port is at the point where it exits, the box should see a very large rise in output at that frequency.
There is a lot of math that can be thrown at this, but the only way to do it is to build first, listen second and measure third.

Shoot first, ask questions later. That's what I always say lol.

Good luck if you embark on this road. I think I posted pics of the ported WO design I have recently either here or in another WO thread. Check that out too.

Robert

the spl idea is catching me. over here,  street a is dominated by a guy who runs 2 dd 10's and a dd z1 hitting something like 142.x beating him with a bit less power is my objective.
so my guess is that a ported wo would be fun to try.
an imperial is on next summer's 'to do list', so the wo will have to wait a little.

[quote author=Adrian D.  link=1157009897/30#35 date=1161170682]the spl idea is catching me. over here,  street a is dominated by a guy who runs 2 dd 10's and a dd z1 hitting something like 142.x beating him with a bit less power is my objective.
so my guess is that a ported wo would be fun to try.
an imperial is on next summer's 'to do list', so the wo will have to wait a little. [/quote]


lol, 142 ?? in truck or ? thats nothing for z1 and 2 x 10" ....

as soon as we finish the WO to plan, we'll test and get a baseline (or should it be bassline?)  then we will play with different aeroports, starting small and short -  it may be a little while before I can post results, as we are starting remote start season here!

are you going to port out the sealed chamber at a 90?  Have to let us know how it does....

[quote author=J_Rock  link=1157009897/30#40 date=1161192864]

Why is this here? and why is it funny? If the mic is a new termlab that is pretty much the max those inefficient subs will do...

[/quote]

because, with Z1 and 2x10" DD subs  in Skoda hachback, i guess it is Fabia, it must go around 150 dB ... my friend with 2x 150W subs and 400W amp , in seald enclosure doing that score (142 dB ) ,in closed trunk car @ peak 49Hz .......