that 2/3 1/3 rule is really just a cookie cutter guideline.
You can tune to whatever you want...the chamber volumes can be whatever you want...there are no rules.
Due to the nature of the ABC enclosure I would make the Net volume for the 11Kv.2 on the large side. Around 1.5-2 cu ft. Port dimensions will be much easier to work with. Excursion is not a problem. The second enclosure resonance helps with that.
Depends on the install...sometimes a regular 4th order bass reflex works better. Sometimes the Aperiodic bi-chamber works better for the install or subwoofer.
So I want to stick with eD's recommendation for tuning to 35Hz. Here is what I've got so far with my calculations. (Feel free to call me out on anything and everything)
When I do use and ABC style enclosure, I like to tune a little lower than that. Just my taste is all, I would actually look at a tune of 30Hz and about 60 Hz. 1.5 in the larger chamber and .75 in the smaller. 4" ports on all 3
__________________
05 Mazda Tribute: Ed stuff: 6000v2 on 120w, 13Ov2 in a PWK Design & 600w, Edead V1
Go for it!! It's all an experiment. Also, though the modeling software says its tuned to 42.3 or whatever, the programs can not take into account an ABC style enclosure. The 1/3, 2/3 "rule of thumb" gives a tuning that is 1 octave differennce. The larger section tuning being 30Hz will make the tuning of the smaller enclosure 60Hz. Did you take into account driver and port displacement?
__________________
05 Mazda Tribute: Ed stuff: 6000v2 on 120w, 13Ov2 in a PWK Design & 600w, Edead V1
I would say that the port is supposed to be "invisible" as far as exactly where you place it. However, if you slide the port back and forth you effectively change the volume of each chamber! You should factor in how much of the port sticks into the chamber when calculating the internal volume of that chamber, but it should not matter how much sticks into one or the other.
I've built ABC boxes before. Keep the gross volume to the same as you would for any other ported enclosure, because it'll act just like an overly large regular ported enclosure.
when you say keep the gross volume the same as any other ported enclosure, does that mean the amount of free air inside the box? (box dimensions - driver - amp - 3 ports) ?
I seem to be constantly doing this out of order.
1) 2.1 cubic feet tuned to 30hz : 7.88" port length
You don't build 'slightly larger'. You determine the volume of all things inside the enclosure (driver displacement, port displacement, etc.) and factor this into your overall gross volume. Your NET volume is what you're left over with (1.4/.7). Think of it like money. Whats the difference between groos income and net income??
And no,y our enclosure will not be tuned to 30 and 60 Hz. Theoretically, the tuning of a dual-chamber ported enclosure actually ends up roughly a half octave above, and a half octave below your originally designed tuning frequency. For that reason, I would aim your tuning frequency at least 5Hz higher.
And increased power handling is a misnomer. It MAY be able to handle more power, but you're now putting much more thermal stresses on the drivers, as your drivers won't be moving a whole lot near now 2 tuning frequencies.
That doens't even make sense. Gross volume doens't mean MUCH, but it is very important when doing all your displacement calculations. It still needs to be right, no matter how you want to look at it.
Linear Mode
