Help needed with box design

[sootshe]

I've decided to put together a set of Cornscala's & want to have the dimensions appropriate to my current Elliptrac mid horn set up , so they will vary a little in the dimensions of the usual styles...........................................To that end, I've downloaded Win ISD to design the dimensions & calculate the port dimensions & my question relates to the dimensions of the port, or ports, as the case may be................................................................I have 4 spare Precision Ports (4" diam) so am keen to use these, as opposed to the standard slot type port in the bottom of the cabinet. I have no experience using Win ISD so I'm just wanting to check things before I start cutting wood. I've attached some screen shots of the results. The programs recommendation when using 2 x 4" ports per cabinet is that they be 3.46 " in length. If I change the design to using just a single port, it says that the port should be only 0.26 inches in length.....................................................................So my question is, are these calculations correct? Maybe I'm not using the program correctly? It just seems strange that with 2 ports the length of the port is 3.46 inches & with 1 port the length computes as 0.26 inches.............................................. Any help appreciated..............................Thanks,...............................John......I posted this under updates & mods, but got no replies.......hoping someone here can advise.

[sootshe]

Second screen shot

[sootshe]

Third screen shot

[sootshe]

Fourth & final screen shot

[pzannucci]

Base your size on the woofer you are using and what would you like the tuning frequency to be too. Using the 2 4" ports may not be optimal based on your end goal. There is a tuning frequency of 40hz in your graphs. Is that low enough? Can you sacrifice a db or two efficiency for lower bass?

Cornscala is really what you want it to be since there is no real Cornscala spec. You need to build it based on how you want the speaker to sound and the components you have or are purchasing. If this is a long term speaker and not built for fun, you should optimize vs. trying to utilize components you already have that are inexpensive.

[sootshe]

Base your size on the woofer you are using and what would you like the tuning frequency to be too. Using the 2 4" ports may not be optimal based on your end goal. There is a tuning frequency of 40hz in your graphs. Is that low enough? Can you sacrifice a db or two efficiency for lower bass?

Cornscala is really what you want it to be since there is no real Cornscala spec. You need to build it based on how you want the speaker to sound and the components you have or are purchasing. If this is a long term speaker and not built for fun, you should optimize vs. trying to utilize components you already have that are inexpensive.

Thanks for the advice Peter. This will be a long term speaker & I intend to use the Crites cast woofer, as that will integrate with the crossovers that I currently have (AP12-500 + AP 15-6000). I don't want to go down the path of re inventing a crossover to suit another type of woofer. My end goal is to get a warmer, fuller sound from the bass than my current ported La Scala design, so I'm not sure how to achieve this, short of building something & listening to it. I modelled with the 40 Hz tuning as most here say that the Cornscala sounds best with that tuning, however, I can sacrifice some efficiency for lower response. I notice when I do that, that the response falls off in the mid bass though. My original plan was to build an Onken cabinet with the Altec 416 series woofer, but I've heard so many stories of trying to get the crossover right,that it just seemed like opening another can of worms. The mids & tops are GPA 399's mounted to Elliptrac's & JBL 2504's.