Common chamber port question
 

I have 4 kenwood kfc1000 10" drivers
In 2.48 cu ft (.62 each)
Common chamber
Optimal airspace sealed and ported is .60 cu ft per driver
Port suggested by kenwood for single speaker speaker is 3"x11"(.039 cu ft) seems to be tuned at 70 Hz
I want around 48 Hz and I have 4 subs
Port calculator says
2 ports
4" diameter
8.8" long. (.767 cu ft) each
Is this correct?

We'll I called kenwood and they say the vented enclosure should be .8 cu ft per driver. This does not match the info that comes printed on the box or any specs you read!
So if I want to vent the box I need to add another .8 cu ft to the enclosure before I can select port size.
Theile and Small parameters point to closer to 1 cu ft each sealed.
I am now confused and don't know what to believe .
It sounds good sealed at .6 per driver but was wanting a little more low

build to these specs




MEASUREMENTS
LENGTH: 46"
DEPTH: 18"
HEIGHT: 16"
GROSS AIRSPACE: 1.49 CU.FT. PER CHAMBER
NET AIRSPACE: 1.25 CU.FT. PER CHAMBER
PORT VOLUME: .16 CU.FT. @ 35Hz
PORT DIMENSIONS: 10 5/8" X 1 1/4" X 20 1/2"

Sealed and vented enclosure will never be the same required airspace.

Yeah
Kenwood support doesn't know about the mis information on the spec sheet.
I also know the sealed box is normally 1/2 - 1/3 smaller than vented.
The shallow displacement just makes it easier to go in small places but doesn't mean optimal performance .
.6 cu ft peaks at about 70 to 80 Hz
Drops off fast
10db down at 50 Hz easy
I can get them to around 1 cu ft with some re configuring
I'll try that and get back with results