The Port Area Thread

[Ray]

Soab..

Ok..bak. Lol

Now, if we wanted peak spl on music with this sub, id go 2.1 with14per tuned to 38

On to a big sub.

Mayhem 12...

First of all if you really want flat with a spl sub...well.....bp box.

Anywho.

I have so many mayhem 12 boxes .....so not funny

2.35 after, with 19per tuned to 3hz above resonant freq of car

If u like neat boxes that sound great... 4th order boxes when done right can be awesome.

Heres one to try for you single 18" guys

2.9sealed side

6.9 ported side

2lbs of polyfill on sealed side

[Ray]

Shit.... With 130sqin tuned to 39

[Ray]

Forward facing cars are a whole other beast, they only do what you tell them to do, ie no transfer function, so tuning is crucial. Use 1\4 wave theory if your going for numbers.

I think most of you could find great use of my database.

I posted a link to it somewhere.. Its still open for you guys. There you can see real world numbers for a large amount of cars.

I try to update it anytime someone comes by for tl testing.

Ill try to make time tonight to add more, and actually go into detail.

[Ray]

Also when I post a box size for a sub, that is assuming that you have clamped rms power, not rated. Also not 5x rms..lol

Am I saying this is the best ever box for your car...nope.

But this is a box that will not suck complete ballsack.

Even I still build numerous boxes looking for the absolute loudest.

Also none of these are spl burp boxes, they are loud daily....not 10hz boxes either.

Like I said before, bp is the way to go safely if you want to play all those 15hz songs.

[Robert8252]

Sooooo. Time to pin that in the AI section as "Ray's Bible" eh? Lol

[fecupe2001]

Let me help you out Ray, this is the link of your sheet, i´ve readed that a few times already

Ray´s termlab data base

[IH8PunkRok]

I think we should all get together at AI sit in a circle with our legs criss crss and just listen to Ray talk

we could learn a lot

[OldsBoomer]

Shit.... With 130sqin tuned to 39

looks like IF you were to use the generalized idea for port area you would use the front chambers volume for the port area on the BP.. hmmm new insight for me on BP finally thank you sir. I will be reviewing your work again and again.

[lowpt]

I have a question regarding port area/size. The general rule has been, use a larger port to reduce port noise. Does there come a point in a slot port that it is too narrow and will cause port noise? For example, a 1 cubic foot box with a port area that is 10"x1.25". This would be 12.5" per cubic foot. This falls into the general rule but, is the narrowness of the port a problem??

[IH8PunkRok]

I have a question regarding port area/size. The general rule has been, use a larger port to reduce port noise. Does there come a point in a slot port that it is too narrow and will cause port noise? For example, a 1 cubic foot box with a port area that is 10"x1.25". This would be 12.5" per cubic foot. This falls into the general rule but, is the narrowness of the port a problem??

the rule of thumb ive heard for that is a 1:8 ratio small to large

for example a port that is 1x9 might make some noise but a 2x4.5 probably wouldnt (given that they were large enough areas in the first place)