my Kappa build

[just-some-guy]

box size. how would 18"w 24"t 32"l do ? by my guesstimation, that is about that same as the standard build. how far off am i ? i would like to go smaller if i wouldn't loose much.

 

[just-some-guy]

oh. i don't mean to be a PITA. but i want to use 1 or 2, preferably 2, ports. instead of the slot port.

thanx a ton

 

[WmAx]

oh. i don't mean to be a PITA. but i want to use 1 or 2, preferably 2, ports. instead of the slot port.

thanx a ton

There is no practical way to use the round ports and get the level of performance you achieve by using the specified slot port. 2 x 4" ports would still cause too much air turbulence, and would have to be around 36" long each, meaning a lot of 90 degree tube joints.

-Chris

 

[lsiberian]

oh. i don't mean to be a PITA. but i want to use 1 or 2, preferably 2, ports. instead of the slot port.

thanx a ton

You can use dual ports on this design that are shorter. but I wouldn't go below a diameter of 3.5" which is high IMO. And you would still be looking at a very long port. The slot design is ideal IMO, but dual ports is achievable. I don't suggest modifiying this design too much. taking the same idea and using it with your dimensions will net you a much better solution. Remember this box was built by people that know their stuff and has been actually tested several times with verified results. Any variation is an experiment.

Listen to Chris. He's got far more experience than I.

I think a folded slot port does a great job. For many designs

 

[WmAx]

You can use dual ports on this design that are shorter. but I wouldn't go below a diameter of 3.5" which is high IMO. And you would still be looking at a very long port. The slot design is ideal IMO, but dual ports is achievable. I don't suggest modifiying this design too much. taking the same idea and using it with your dimensions will net you a much better solution. Remember this box was built by people that know their stuff and has been actually tested several times with verified results. Any variation is an experiment.

Even dual 4" ports is going to cause substantial compression around the port tuning frequency. I can not recommend this if the subwoofer is intended to produce high, clean output down to it's tuned frequency.

Now, if one wants to use ports as just an 'extension' helper, then the case is different. That is where you use ports to extend lower and flatter than sealed, but do not intend to use the subwoofer down to the tuning frequency of the port. In this case, you will set your subsonic filter to be ABOVE the port tuning frequency. For example, in this case, using dual 4" ports, where the ports are tuned around 20-21Hz, you would set the subsonic filter to about 25-26 Hz, and this would prevent the air velocity from becoming too high in the port.

-Chris

 

[just-some-guy]

ok, so your sayin my box size is good ?

is there a good plate amp that would give the same result ? just askin, as this, if possible/practical, would work out better for me.

 

[lsiberian]

Even dual 4" ports is going to cause substantial compression around the port tuning frequency. I can not recommend this if the subwoofer is intended to produce high, clean output down to it's tuned frequency.

Now, if one wants to use ports as just an 'extension' helper, then the case is different. That is where you use ports to extend lower and flatter than sealed, but do not intend to use the subwoofer down to the tuning frequency of the port. In this case, you will set your subsonic filter to be ABOVE the port tuning frequency. For example, in this case, using dual 4" ports, where the ports are tuned around 20-21Hz, you would set the subsonic filter to about 25-26 Hz, and this would prevent the air velocity from becoming too high in the port.

-Chris

Certianly, but still I think if that is your aim then shrinking the box would be much wiser. I believe this sub can be used in half the size with a 25hz extension. Still I found that waste for the driver hence the reason I sold them. There are many small subs solutions superior to the Kappa. The Kappa is a budget build IMO. The drivers are fairly efficient, and the cost low.

What is your suggested max speed for port air velocity?

 

[just-some-guy]

Even dual 4" ports is going to cause substantial compression around the port tuning frequency. I can not recommend this if the subwoofer is intended to produce high, clean output down to it's tuned frequency.

Now, if one wants to use ports as just an 'extension' helper, then the case is different. That is where you use ports to extend lower and flatter than sealed, but do not intend to use the subwoofer down to the tuning frequency of the port. In this case, you will set your subsonic filter to be ABOVE the port tuning frequency. For example, in this case, using dual 4" ports, where the ports are tuned around 20-21Hz, you would set the subsonic filter to about 25-26 Hz, and this would prevent the air velocity from becoming too high in the port.

-Chris

interesting (pretending to look like i know what i am talking about )

i don't think i have to have absolute perfection out of these. i live in a condo, so i couldn't use max db and/or sub 20hz very much. though sometimes i could.

i have never heard REAL sub before. but, tomarrow, i am going to a somewhat local get together. few different real subs, projector, etc. so i expect i will learn a lot.

 

[just-some-guy]

i going to buy my wood. be back in a few.

 

[lsiberian]

interesting (pretending to look like i know what i am talking about )

i don't think i have to have absolute perfection out of these. i live in a condo, so i couldn't use max db and/or sub 20hz very much. though sometimes i could.

i have never heard REAL sub before. but, tomarrow, i am going to a somewhat local get together. few different real subs, projector, etc. so i expect i will learn a lot.

Honestly I think you are best off sticking to the designs port size and design.

 

[just-some-guy]

ok. $104. 2 3/4 x 4 x 8 birch, 1 tightbond glue, and 2" screws.

my box size. that is doable ? i'm ready to start cuttin right now.

btw, i looked at the 4" pvc, that there is some big holes. anyway.

 

[lsiberian]

ok. $104. 2 3/4 x 4 x 8 birch, 1 tightbond glue, and 2" screws.

my box size. that is doable ? i'm ready to start cuttin right now.

btw, i looked at the 4" pvc, that there is some big holes. anyway.

There is a cut sheet somewhere, but I believe you will need a tad more than 2 sheets. Lowes sales 1/3 of a sheet.

You don't need screws. Make sure you cut straight Or you will be sanding a lot.

 

[just-some-guy]

i can use that shape box, it is too wide. i hope/plan to go to a LARGE screen, sometime in 2-3 years, maybe sooner. and there just wouldn't be enough room on my wall for the screen/tv, speakers and those subs. the wall would be jam packed, even with my 18" wide cabunets. or i would have to get a smaller screen/tv, and who wants to do that .

 

[ParadigmDawg]

Isn't it just:

Cut list (Use 3/4" cabinet grade plywood):

Front baffle: 21" x 24"
Rear baffle: 22.5" x 24"
Sides: 21.75" x 24"
Top/Bottom: 22.5" x 22.5"
Cross brace (large): 16.5" x 21"
Cross brace (small): 6.25" x 21"
Port bottom:
2x 18" x 3"
17.25" x 14"
Port back:
2x 24" x 3"
18" x 14"
Port top:
2x 13.75" x 3"
13" x 14"

Or is it different then Andrew's simple KAPPA?

There is a cut sheet somewhere, but I believe you will need a tad more than 2 sheets. Lowes sales 1/3 of a sheet.

You don't need screws. Make sure you cut straight Or you will be sanding a lot.

 

[just-some-guy]

outer boxs are built. just screwed together, for now.

 

[lsiberian]

i can use that shape box, it is too wide. i hope/plan to go to a LARGE screen, sometime in 2-3 years, maybe sooner. and there just wouldn't be enough room on my wall for the screen/tv, speakers and those subs. the wall would be jam packed, even with my 18" wide cabunets. or i would have to get a smaller screen/tv, and who wants to do that .

Just use a wall mount. Or even better go PJ and mount a screen

FYI you can put the subs anywhere in the room. They don't have to be in the front. You can even use them as end tables. This is cabinet grade wood your using.

 

[just-some-guy]

they really wouldn't fit anywhere else. my box is just a little under the 23x23x25 of the original. they are sitting in there places, and they are getting close to real big. though the final finishing will make em look better/more appropriate.

 

[sawzalot]

they really wouldn't fit anywhere else. my box is just a little under the 23x23x25 of the original. they are sitting in there places, and they are getting close to real big. though the final finishing will make em look better/more appropriate.

The boxes are big when I brought mine into the house they looked like they doubled in size I didnt get a good perspective when they were outside.Post some pics when you get a chance,thanks,Sawz.

 

[ParadigmDawg]

Wait until you see this 45" tall monster I am building.....

The boxes are big when I brought mine into the house they looked like they doubled in size I didnt get a good perspective when they were outside.Post some pics when you get a chance,thanks,Sawz.

 

[lsiberian]

Wait until you see this 45" tall monster I am building.....

.....