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View Full Version : Solution to the Swappable Port Dilema



Omarvelous
05-14-2004, 05:24 AM
OK, i have devised a plan on how to make easy to use swappable ports.

I'm sure it has been done already, i just felt that i'd share it with every1 since it has been a reoccuring topic recently.

In my example I will be using a 15" XXX and 1" MDF.

Here is a diagram that i made with fireworks.

http://www.rit.edu/~olj2538/burban/swapport.gif

Pretty Easy to understand.

I apologize for the size of the picture, my resolution is very high, therefore not as big on my screen.

It's basically making 3 seperate sections. The modified top board piece, the port mount piece, and the port. Can be easily adapted/added to any box if you already have it created.

The port will be mounted flush with the Top board ontop of the port mount piece.
You may use tnuts and a rubber seal to ensure as minimal airloss as possible.

The port piece is given one inch around to mount with a tight and perfect fit both with the top board and the port mount piece.

Any?s Feel free to Post up and i or any1 who understands/has done this can answer.

This is how i will be doing mine for the summer.

It's much better then the other methods i have read about because

- Saves time - some suggested actually opening the box and removing port section, This way is WAY faster.
- Saves confusion - unlike the suggestions that state to add pieces, you don't have to account for any loss in volume


Admins might wanna Sticky this :thumbsupw

Omarvelous
05-14-2004, 10:05 AM
Oh yes she's a beauty! :D

I won't be doing this for another 3 months or more so maybe some1 will get to it b4 me.

JonnyBlaze
05-14-2004, 10:53 AM
im designing something similar. im using 2 15's and the port will be on the same side as the speakers. ill post the plans once they are finalized.

JB

Omarvelous
05-14-2004, 03:34 PM
im designing something similar. im using 2 15's and the port will be on the same side as the speakers. ill post the plans once they are finalized.

JB


Yea it can be done on that side.

I'd recommend however doing a double baffel.
The bottom layer mount the sub and use that as the port mount also
Then your port assembly would be flush with the top layer of the baffle which is flush/close to flush with your sub surround.

JonnyBlaze
05-14-2004, 04:07 PM
let me ask you another question. i used the port area calc on loudspeakers101.com and telling it 2 15's, with 32mm xmax, which the xxx's have and tuned to 27hz, it says it needs a port area of 179"!! my port was going to be 15x4, 60sq inches. could they be right? would going that much smaller cause alot of port noise? im close to scrapping what i have so far, using your double baffle idea and putting the port on a longer edge. it dosent take me long to draw up new plans.

thanks

JB

JonnyBlaze
05-14-2004, 04:40 PM
thanks for the tip ;)

im still working on a new design to give me a lil more port area.

JB

JonnyBlaze
05-14-2004, 05:26 PM
I don't know why people use the loudspeakers101.com calculators ... The only time they're correct is by coincidence ...

Use the calculators @ BCAE1.com, diysubwoofers.org, or use WinISD Pro 0.50a7 ...

i been wasting my time over there. just realized on the port calc, if you swap the height & width numbers, the answer shouldnt change cause the port area dosent change, but it changes alot. i knew i needed that formula in excel for a reason.

JB

LoneRanger
05-14-2004, 11:12 PM
heh....

i've built several boxes with swapable ports like that....if i can find the pics i'll post them later

JonnyBlaze
05-15-2004, 10:36 AM
http://24.218.132.26:81/sweeps/blazer.jpg

heres my design so far. the volume after the port and brace is 8cu feet. the port is 14x3x 13" long, which should tune it to 28hz. the shorter port will be 2.5" long and tune it to 42hz. is that going to be too short?

will port noise be a problem?

JB

Omarvelous
05-15-2004, 11:59 AM
http://24.218.132.26:81/sweeps/blazer.jpg

heres my design so far. the volume after the port and brace is 8cu feet. the port is 14x3x 13" long, which should tune it to 28hz. the shorter port will be 2.5" long and tune it to 42hz. is that going to be too short?

will port noise be a problem?

JB

REAL Fing SWEET!! What program did u use?

smullen
05-15-2004, 12:09 PM
REAL Fing SWEET!! What program did u use?
I was thinking the same thing..

JonnyBlaze
05-15-2004, 01:15 PM
its a program called inventor. i use it for work.

i used autocad also.

JB

JonnyBlaze
05-18-2004, 01:55 PM
here is a new box i just designed. its tunable from 23hz to 42hz. im going to make a plug for 27, 35 and 40 to see what i like.

JB

http://24.218.132.26:81/sweeps/blazer01.jpg
http://24.218.132.26:81/sweeps/blazer02.jpg
http://24.218.132.26:81/sweeps/blazer03.jpg