custom fiberglass PORTED enclosure

[req 5,000+ posts]

ok. im making this very soon, and i have yet to find out this one problem.

this diagram shows how i will do this;

1. create the MDF contour of the trunk for the BASE of the enclosure

2. create PORT tuned to 37hz in 1.2cubes

3. lay tape and bags to keep fiberglass area clean inside trunk

4. instert mdf with port securely connected into trunk in final position on top of tape

5. start laying fiberglass to creat a relief of the trunk that is connected to the MDF base\port to create the rear\bottom\port of the enclosure

6. create baffle (flushmout)

7. mout baffle on the mdf\fiberglass\port in desired angle\location

8. stretch fleece so that the internal volume is larger than 1.2 cubes net - around 1.5cubes

9. after enclosure is complete (enough layers and everything) insert enough wood to lower net internal volume to 1.2 cubes.

now i should have a 1.2 cubes @ 37hz right? right!

now the only thing i dont know how to do is make the port the right size because i dont have box dimensions... anyone help me just making this port? this is all i need to get this done. i made a thread eairler about this, but noone really understood what i was doing making the port before the box. all i need is a genaric 1.2cuft@37hz port dimensions. thats it. no box, nothing- just a port.

id like to to be wide and short... like 10"~15" wide, 2~5" tall, and 10~15 deepl. anywhere close to those sizes are fine... smaller is fine too.

anyone have any input or help about making a port without an enclosure?

Click to read more...

 

[Black_Jesus 10+ year member]

^something ive never seen done before i wish you luck my friend //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[req 5,000+ posts]

^something ive never seen done before i wish you luck my friend //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

thats one reason why i wanna try this =)

i want my 10 to put out more SPL and i want it to look better. i might paint depending on the quailty this turns out.

anyone help me with port calculations tho?

 

[BiaBia 10+ year member]

You can make an entire box using MDF, then build a frame with stilts and fleece for the fiberglass.

 

[req 5,000+ posts]

You can make an entire box using MDF, then build a frame with stilts and fleece for the fiberglass.

thats way to complicated dude.

all i need is dimensions for a port. i dont wanna waste MDF eaither- this way is gonna be much eaiser, i just need the internal volume of a port = 1.2@37hz.

any help jmac? //content.invisioncic.com/y282845/emoticons/bawling.gif.6287aa5d1d447c8af063fc9466e822ef.gif

 

[Nikuk 5,000+ posts]

20 sq in's of port for a 1.2 cu ft enclosure is going to be pretty long.

a blind port calc (not counting driver displacement cause its unknown to me or port wall thickness) for 1.2 cu ft with 20sq in of port = in excess of 3' long.

a blind port calc for 1.625 cu ft with 20 sq in of port = 29" deep. you end up with 1.199 net volume (before sub displacement)

how much does your sub displace?

as an alternative, would you be willing to make your port out of fiberglass? reason i ask is cause it will make the thickness alot less then 3/4" and save you some more volume.

 

[req 5,000+ posts]

20 sq in's of port for a 1.2 cu ft enclosure is going to be pretty long.
a blind port calc (not counting driver displacement cause its unknown to me or port wall thickness) for 1.2 cu ft with 20sq in of port = in excess of 3' long.

a blind port calc for 1.625 cu ft with 20 sq in of port = 29" deep. you end up with 1.199 net volume (before sub displacement)

how much does your sub displace?

as an alternative, would you be willing to make your port out of fiberglass? reason i ask is cause it will make the thickness alot less then 3/4" and save you some more volume.

ok dude, dont worry about displacement of the box. i can deal with that =P

whats the thinest MDF that is strong enough to make a port with... .25"?

all i need is the inner dimensions of the port, from there i can figure it out. or just let me know how many square inches the port has to be to come out as 37hz for 1.2cubes. dont worry about wood thickness or driver displacement. the internal volume WILL BE 1.2 CUBIC FEET AFTER ALL DISPLACEMENTS (INCLUDING PORT AND WALL THICKNESS)

this is the nature of how it is being built.

all i need is L x W x H (internal) dimensions OR how many INTERNAL cubic inches i need for the port (you said 20sq inches?)

whats the formula to calculate L x W x H into sq in, isnt it like (L)(w)(h)= X(1728)?

 

[plazman 10+ year member]

so ur saying u can create the port before u make the enclosure ?

 

[req 5,000+ posts]

exactally. this way i can stretch the fiberglass OVER the port and come out with a pimp *** ported enclosure.

why not? as long as the internal volume is 1.2 cubes after sub displacement and port displacement everything should work.

im planning on sealing the wood with resin and extending the port with 1\2 the width with a temp foam thing, filling it with water and getting it to 1.2 cubes exactally.

 

[Nikuk 5,000+ posts]

ok dude, dont worry about displacement of the box. i can deal with that =P
whats the thinest MDF that is strong enough to make a port with... .25"?

all i need is the inner dimensions of the port, from there i can figure it out. or just let me know how many square inches the port has to be to come out as 37hz for 1.2cubes. dont worry about wood thickness or driver displacement. the internal volume WILL BE 1.2 CUBIC FEET AFTER ALL DISPLACEMENTS (INCLUDING PORT AND WALL THICKNESS)

this is the nature of how it is being built.

all i need is L x W x H (internal) dimensions OR how many INTERNAL cubic inches i need for the port (you said 20sq inches?)

whats the formula to calculate L x W x H into sq in, isnt it like (L)(w)(h)= X(1728)?

mmkay then.

I dont have BBP6 off hand cause I'm at work. But longhand (with the formula in Excel) 20 sq in (Length x Width) of port opening (internal) you need 29.08" depth (resulting in an internal port volume of 0.336574 cu ft). This is for 1.200 cubic ft net to 37.0003 hz.

Frequency=0.159*(((AV*(1.84*10^8))/(Vb*(LV + 0.823*(AV^0.5))))^0.5)

Av=Port Area

lV=port length

vB=Box Volume

Take pictures!!!

 

[Nikuk 5,000+ posts]

so ur saying u can create the port before u make the enclosure ?

yes, yes, yes. its just more involved.

 

[btnhfan 5,000+ posts]

good luck with this. post up pics!

 

[EFFENDI 10+ year member]

Sounds like a cool idea, cant wait to see the results!

 

[req 5,000+ posts]

mmkay then.I dont have BBP6 off hand cause I'm at work. But longhand (with the formula in Excel) 20 sq in (Length x Width) of port opening (internal) you need 29.08" depth (resulting in an internal port volume of 0.336574 cu ft). This is for 1.200 cubic ft net to 37.0003 hz.

Frequency=0.159*(((AV*(1.84*10^8))/(Vb*(LV + 0.823*(AV^0.5))))^0.5)

Av=Port Area

lV=port length

vB=Box Volume

Take pictures!!!

ok, this is going in the right direction. hopefully i can get the base and the port made up tomrrow after work;

but you said its 29.08" deep. how wide and tall? you said all i gotta do is get 20cuin of internal volume for the port and it will be 37hz for 1.2cube box(after displacements)?

whats the length\\width\\height of the port you are describing?

i used the (base)(width)(height)=cubic inches formula to get this;

2x5x2=20 cubic inches.

you said i need 20 cubic inches for 37hz. those (internal) dimensions equal 20cuin of port area, correct? am i wrong with this?

how did you get 20cuin for a 1.2cube@37hz?

any help here JMAC? (i know you are reading this //content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif )

 

[Bavarian3 10+ year member]

good luck with that, i cant wait to see the result. u gona paint the box? if so GOOD LUCK with that as well, i give u mad props for trying this.