im stupid but I need clarification on this port please

[twistedmind 10+ year member]

is that measurment length per port, or is it over all length and I make each port to half that length?

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[SSS 18734 5,000+ posts]

That number would be the length of EACH port.

 

[twistedmind 10+ year member]

seems awfully long considering its only a 2.3 cubic foot box, what m I doing wrong?

 

[SSS 18734 5,000+ posts]

I doubt you're doing anything wrong unless you typed in the parameters incorrectly. That's actually a rather large pair of ports. What is it tuned to? Looks to be around 35hz according to your graph.

If you want to decrease port length, you can do several things.

1. Increase box volume

2. Use a single port

3. Use smaller ports

3. Tune higher

 

[twistedmind 10+ year member]

okay so 2.314 cubic feet enclosure for one 12" fi Q

I need 36" of vent area per FI useing the 16" per cubic foot of volume ( they say I can use as low as 12 " per cube) , should use 12" to get a shorter port?

I just can't afford port noise as the ports will be less than 2 feet from my head.

and my box is only 21" deep, and im going to have to use square ports as its a glass box and I didn't figure for a slot port when I built it.

would a aero or multiple aero ports work better for me?

 

[cycloneman 10+ year member]

What freq are you trying to tune to?

 

[twistedmind 10+ year member]

I doubt you're doing anything wrong unless you typed in the parameters incorrectly. That's actually a rather large pair of ports. What is it tuned to? Looks to be around 35hz according to your graph.
If you want to decrease port length, you can do several things.

1. Increase box volume

2. Use a single port

3. Use smaller ports

3. Tune higher

I can not increase box volume as its fiberglass and done except for my square port inserts

Single port is a option don't know if I can get the necissary vent area that way though

Smaller ports are a option but I can't risk port noise

32Hertz is the manufacturers reccomended tuning for a daily musical street beater

 

[twistedmind 10+ year member]

What freq are you trying to tune to?

32

 

[IonSQL 10+ year member]

Are you trying to insert ports into a box that is already 2.3cf?

 

[twistedmind 10+ year member]

i think im ****ed

if I make the port horizontal I have 28.5 total inches from wall to wall

if I go vertical I have 19.5 inches

the port can be no deeper than 3 " vetical mount

horizontal mount ive got some room to play with

 

[twistedmind 10+ year member]

Are you trying to insert ports into a box that is already 2.3cf?

yes, I put off port calculations because I made the box from fiberglass and didn't know how big it would end up being

ill post a pic

 

[twistedmind 10+ year member]

pic of box with measurments

 

[IonSQL 10+ year member]

Once you put the port in the box, it will no longer be 2.3cf.... it will be 2.3cf minus the space the port takes up //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[twistedmind 10+ year member]

Once you put the port in the box, it will no longer be 2.3cf.... it will be 2.3cf minus the space the port takes up //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

negative ghost rider, its sitting around 2.5 - 2.6 right now. I did my math a little small to account for port displacment.

 

[SSS 18734 5,000+ posts]

I used a simple calculator to come up with a few figures.

You could use a 6" flared aeroport. That would give you about 29 sq.in. of port area and it would have to be about 29 inches long.

A 4x10 square port would give you a good amount of port area and would need to be about 40 inches long. If you tuned it a little higher to 35 hz, that number would drop to 32 inches.

Also, to reduce port noise without changing the box, direct the ports as far away from you as possible. Downfiring muffles port noise. Also keep in mind that you more than likely won't experience port noise during normal listening volume, even if the port is too small. It usually doesn't become apparent until it's getting pretty loud.