[wbarnes570]

My first ported design. Would like some comments on whether this box will work well or not. It is intended for 2 12" Kenwood KFC-w3011's that I currently have in a sealed enclosure.

Box specs (or what they are supposed to be at least)

net volume - 3.2 cu. ft.
gross volume - 4.84 cu. ft.
tuning frequency - 33Hz
port length - 32 1/8" + 1 3/4" end correction

I would like to know if 33Hz is a good tuning freq. for this enclosure/subs. I chose 33 due to a few articles that I read. Any comments, opinions, or advice are welcome.

P.S. The volumes may be a bit off because I Factored in braces and didn't add any the drawing yet.

 

[MadBrad]

So where did you get the dimensions from? It looks fine as long as those numbers are right for that driver.

 

[wbarnes570]

The owners manual calls for 1.0 - 2.0 cu. ft. per sub in a ported enclosure with 1.5 cu. ft. being recommended. I went with 1.6 cu. ft. per sub.

 

[neuspeedescort]

33hz is pretty low for daily use. i wouldnt recommend goign lower then 38hz.


NEUMAN

 

[MadBrad]

The owners manual calls for 1.0 - 2.0 cu. ft. per sub in a ported enclosure with 1.5 cu. ft. being recommended. I went with 1.6 cu. ft. per sub.

What did it say fer port size?

 

[wbarnes570]

Kenwood called for a 3" x 7" round port with no recommendations for slot port boxes. To neuspeedescort, I am curious why you say not to go below 38Hz, because everything I read and everyone I talked too about port tuning said that higher is for SPL and lower is for SQ, and most article's I found about it recommended 33Hz as a good split between SQ and SPL. I am not saying that you are wrong I would just like some info on it.

 

[neuspeedescort]

i use this calculator at least 3 times a week.

http://www.reaudio.com/speaker_box/LPort_Box_Calc.html

a couple of my friends have programs that will determine the correct port tuning hz. if the port is tuned to 33 that doesn't mean its going to be making it's peak at 33.

like my next box will be port at 30hz but the air space and speaker factors into it being a peak at 38hz and dropping off around 80hz.

NEUMAN

 

[wbarnes570]

Ok I'm a little confused. With that calculator, if I want my tuning at 33Hz then I should get the Tuned Frequency on the calculator to say 33 right? Also I was told to never trust calculators and to do all the math by hand (which is what I did). What is this program taking into account that I didnt? I factored in all my displacements, (I wanted 1.6 cu. ft. per sub after all displacements so when I did my calculations I used 3.2 cu. ft. b/c thats what the subs would see).

 

[neuspeedescort]

of all the online calculators i have seen this is the one i trust the most. you see the website name. RE isn't audiobahn or jensen. LOL that calculator will not factor in your speakers displacement. you will have to subtract or add as needed for that. i will tell you this tho. JL doesnt tell me to put my W6 in a 1.6ft3 vented box but the computer program my buddy has does. im going to trust the program over JL. specs with a speaker are "generic" its to help you not blow things up and them have to warantee everything. look into PWK designs if you want more reasons to not always trust manufactures specs.

my W6 is supposed to be in a 1ft3 ported box. my tuning and range of play is very short there. its hard to explain sometimes. i know your not dumb or you wouldn't be asking the questions you are.


NEUMAN

 

[wbarnes570]

I will look into that. Also do you have any idea what the RE calculator is trying to tell me, if the square port length 1 is 12" and the square port length 2 is 8", the center line of the port would be 24 1/4" rite? But the calculator tells me that the total port length is 26". I can not figure out where it is getting that extra 1 3/4". If you can shine some light on this I would appreciate it b/c it has me quite confused. Thanks for the not dumb comment BTW I appreciate it, I always try to figure my problems out myself before asking for help, and when I do ask I always try to word it perfectly so I don't look like an idiot.

EDIT: I forgot to mention that the port width is 3 1/2" and height is 14". Hard to figure out if my center line measurement is correct without the width of the port lol.

 

[wbarnes570]

Ok I have played with the RE calculator for a while and I'm a little less confused. I still don't know where it is coming up with the extra 1 3/4" on the total port length but I have come to realize that the calculator states box volume (gross) and port displacement separately. Meaning if it says 4 cu. ft. as box volume and .5 cu. ft. for port displacement, you have to add the two together for your total gross volume of 4.5 cu. ft. These numbers were just an example BTW.

 

[neuspeedescort]

port area should not be part of your ft3 number. its seperate from the box. it took me some time to understand that. so your total internal "box" volume may be 4 but the port is another .5. it plays no factor in your airspace technically.


NEUMAN