Marshall white and/or Trevor Eaton Help!

 

Anonymous
 
I used this link - http://www.carstereo.com/help/articles.cfm?id=31

and did the round port calculator but i thought of something since 1 4" round port equals 12.57 sq.in. couldn't i use that theory to get my port size for example on the site I typed in for Quantity of ports-4 then Enclosure Volume-5cu.ft. then Desired Tuning Frequency-32hz and last,Desired Port Diameter-4in. and it came up with a 23.53 Vent Length so multiply the 12.57 which equals a round 4" port x 4 which is the Quantity of ports equals 50.28 sq.in. of port area with a 23.53" vent lenght.Will this work?
 

Silver Member
Username: Lexuscoop

Post Number: 775
Registered: Dec-05
dam dude, i know im not one of them... but thats some scientific talkin right there LOL^_^
 

Anonymous
 
thanks lol
 

Gold Member
Username: Southernrebel

Monroe, Louisiana USA

Post Number: 2135
Registered: Mar-04
Are you trying to ask if 4 4" ports will be the same length as one 50.28sq in port?

If i looked at your post correctly...the answer is no.

here is why:

when you put more than 1 port in your box you in effect tune each port for its percentage of the boxes volume.

---EX. w/ 4 4" ports in a 5cuft box...you would divide total box volume by the number of ports and find the port length. since you have more than 1 port the sound waves react differently than if you had only 1 port.
-----1.25cuft w/ 1 4" port...the port would have to be 23.53" long. then you just scale that up to 4 4" ports w/ 5cuft...each port would be 23.58" long.

w/ 1 port 50.28sq inches, you dont have to do this. the box will only see one place for the sound waves to excape, so you just calculate port lenght w/ 1 50.28sq in port.
---if you have 1 50.28sq in port and tune a 5cuft box to 32hz...the port would only have to be 20.61" long.


get it?


here is a tutorial on multi-port boxes:
http://mobile.jlaudio.com/support_pages.php?page_id=165
 

Gold Member
Username: Southernrebel

Monroe, Louisiana USA

Post Number: 2136
Registered: Mar-04
it didnt bump....

so BUMP!!!
 

Anonymous
 
i was just wondering could i use that site and my formula to convert to sq.in. port it seems like everything matched up put the lenth of the port? And does WinISD tell you the exact box size the exact port size and the exact port lenth cuz if it does im dont have a clue on how to use it
 

Anonymous
 
why didnt it bump?
 

Anonymous
 
b
 

Anonymous
 
b
 

Anonymous
 
bump
 

Gold Member
Username: Tdeaton1021

Near Tampa, Florida USA

Post Number: 1824
Registered: Sep-04
anon- marshal is correct. and as for what your asking. he said no lol. the site has a square port option so you can use that. why are you calculating round ports when your going to make a square port.? also make note that a square port and a slot port do not have equal port length at a given frequency. the site also has the slot or nonslot option. also, if your box is 5cuft before sub and port displacement, remember that the volume you enter in that site is for NET volume, or the volume after sub and port displacment.

hope that helps, ask more questions if you need to.
 

Anonymous
 
Oh man im so confused is there a site that helped you guys learn all this?
 

Gold Member
Username: Tdeaton1021

Near Tampa, Florida USA

Post Number: 1829
Registered: Sep-04
this one! lol ive learned alot through this site.

one thing i learned is a lot can be learned at www.bcae1.com lol

also i think its www.the12volt.com
 

Anonymous
 
k ill try them sites but i think all i need is a real good Very Detailed example cause i really want to learn how to do this
 

Gold Member
Username: Tdeaton1021

Near Tampa, Florida USA

Post Number: 1836
Registered: Sep-04
patience, you wont learn in 5 minutes.... stick with it.

and ummm, please register, its free and easy
 

Anonymous
 
Im registered, but i dont have patience lol its just biging me to death trying to figure it out its not like i dont know how to do math its just i dont know what to divide and/or multiply.
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