128h cabs

[kawmic]

I've got 4 128h's and 2 pr300 passives. If anyone has anything lying around, that can be used to calculate a big sub. cab. for those 6 speakers, pls. post them.
Or, if you've got some good ideas, how to get the cab. calculated the right way, pls. let me know.
Don't care if the cab. is BIG!!
Thanks in advance Michael

[pos]

A single PR300 will likely not be enough for a pair of 128H.
You would need a pair of them per side, or maybe a 15" passive.
All in all, you would probably be better served with simple ports, as passive only have an edge when looking for small cabs anyway.

As for your box calculation, try installing WinISD: it is really straightforward to use (the "pro" version is a bit more complicated) and will calculate the ports dimensions for you.

What is the intended frequency band and application?

[kawmic]

The intended frequency is around 25 hz. It's supposed to be used as a sub in a surround configuration, where the front is loaded with 2404, 2445 and 2118.
Where the 2118 is the least sensitive ( ca. 97dB). So in order for the sub to get up there, i'll need all 4 128h's. According to my calc.

[pos]

If you are going to use 2118, you could try to run the 128H as woofer instead of subs, up to maybe 300Hz. The 2118 is not meant to go low enough to meet a sub (or in pair, in assisted alignment...)
The 128H is not the best 12" for subwoofer duty (limited xmax by today standards, especially for HC duty), but it is a very good woofer. It was used up to 800Hz in the 4412 studio monitor, and it was also used by Westlake in some of their tower speakers.
A pair per side would be a perfect match for a single 2118.
In fact if you have a large enough horn you could even simply drop the 2118...
On the other hand if you keep the 2118 you could drop the 2445 and go directly to the 2404. Simplification is almost always a good thing.

Are you going to run the system active?

some inspiration:
http://www.westlakeaudio.com/Speaker.../tower-12.html
http://www.westlakeaudio.com/Speakers/Hi_Fi_Series/tower_hr-7.html
http://goldsound.net/kit11.htm