bkolfo4

If you want to use a round port, a 4" is enough for that driver. ~12 sq in. That is enough for a 10" sub with 6mm xmax. It has a low Fs, so 22-25 Hz tuning will definitely work.

Fi Q 12" makes a nice home sub.

The 8" subs are awesome. . .

Almost killed me and broke me from drinking. . .

My good friend runs the 15" in 2.5 cu ft PORTED, and it sounds awesome!

VERY nice amp.

Assuming 4.75 ft net: (4) 4": 23.26" long for 33 hz, 20.35" for 35 hz (2) 6": 25.7" for 33 Hz, 21.8" for 35 hz Brian

Then he needs total weight, not magnet size. . .

The box volume method is a very simplified estimate.

2.25 with 40 inches works.

Did you notice that calculator did not ask you for the box volume to determine the required port area? Sorry, I had to say it

The required port area will depend on the sub, the volume of air it can sweep (Vd), how much power you will use, and tuning frequency. Using anything else to size the port is an estimate or guess. . . You can use smaller ports if they are flared.

not that I agree with running at such a low ohm load, but how much current is required at the input of the amp is based on efficiency and output, not what ohm load it is driving. True, most amps are not as efficient as the load drops, but it is not enough difference to require another bank of batteries or additional alt. If it is, that would be an amp to stay away from.

Double post

Why relate it to box rise? I bet if you doubled the power going to the sub in free air the impedance would rise. . . The problem with impedance rise and music is that it is very possible to have certain frequencies that fall to or slightly below the nominal impedance. This could easily cause your amp to go into protect mode. Been there. . .

I think you are mixed up on what "box rise" actually is. To answer your question, yes impendance will increase with additional power due to increased heat and power compression.

If it is not flared, a round port requires the same port area as a slot port. Once again, port area is not related to box size. . . Brian

At least 2 4" aeros will be good.

Box volume, port area, and tuning frequency are the choices. Port length/volume is set based on your 3 choices.

I would not do a single 4" with a square 12" sub, unless the port has a good flare or you are not running much power. As far as placement, I do ports on opposite sides and have never had a problem. There will be some who disagree. If one side is sealed off from the other side (like tight fit in a trunk), it may have a screwed up frequency response, but no worse than running the port of a standard ported box through the rear deck. If it is just a box in a trunk that the sound can pass around, should be ok.

So, I am always up for a good debate. . . What makes (2) 6" ports have more/less output and port noise in 2 different size boxes? Not overall efficency, just talking about the ports. And don't forget, the same port size with the same tuning will be shorter in the larger box. . .

But that is not correct. . .It does not depend on box size at all. Those are just approximations so people are not constantly asking how much port area they need, since the true mount of port area required for a port to operate correctly without compression is almost never achieved in a vehicle. If I have a BTL 18 on 4000 watts tuned to 35 Hz in 6 cuft vs 10 cuft, I do not need a different size port. If I have a BTL 18 on 2000 watts vs 4000 watts in the same 10 cuft, they do not require the same amount of port area. Port size is correctly determined by cone displacement and tuning frequency. . .

Which would be volume, not area. . . we are looking at sq-in, not cu-in.

Actually my friend, it does not. . .but it is a nice approximation for those that cannot figure out how much port area they really need. . .

I was at a monster truck jam last year, just happen to be shooting a video when a truck blew an engine. Shot two more videos before I realized the big boom killed my mic. Must have overload protect - I rebooted my iPhone and it worked again. . . Brian