4th order help

[the Answer 10+ year member]

can u guys help me or give me links that would help me with 4th order boxs.

i need things like how much air space sealed and ported and how big of port ect. any help would be nice so then i can design these for other people.

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[Jroo 10+ year member]

There are a couple on here that will help, but will charge. It sounds like you are trying to figure out a design for someone else? 80 inches did a 4th order for me using some very cheap close out woofers. A lot of people were surprised when they listened to them and then heard how much money I actually put out on the set up. I think both woofers cost me 40 bucks from credence.

 

[the Answer 10+ year member]

well im not looking for a design, just help in desinging them.

 

[galacticmonkey 5,000+ posts]

Don't design them for others until you have built a few for yourself.

They are pretty easy to do.

 

[galacticmonkey 5,000+ posts]

Don't design them for others until you have built a few for yourself.

They are pretty easy to do.

 

[the Answer 10+ year member]

well i still need to know what to do. i use winISD and google sketchup for my other boxs, so i just need info on box sizing and i think i will be ok.

 

[RAM_Designs 5,000+ posts]

winISD is worthless for BP's, from what I've heard.

 

[Jroo 10+ year member]

All i know is there is a fine line with 4th order or any bandpass. Some sound like flea market poo and others sound like the cleanest bass you would ever hear.

 

[the Answer 10+ year member]

well thats why i want to know what im doing

 

[the Answer 10+ year member]

bump for help

 

[galacticmonkey 5,000+ posts]

This is what I know:

• Sealed chamber determines power handling, somewhat response.
  
• Ported chamber determines efficiency, also has to do with how steep the cutoffs are.
  
• Bigger the port, the better, to an extent. Anywhere up to around 30in^ of port per cubic foot of ported airspace works great for SPL and setups where you are looking for good numbers. Less control of cone.
  
• Smaller the port, the more gradual the roll off points, but with less efficiency.
  
• Basically I try for a roughly sized sealed chamber, and then build the ported chamber as big as possible usually. Can be different based on the subs or the desired sound, but Ive done some pretty crazy ratios, like 1:4-1:5 and they always sounded great with a nice peak right where I wanted it.
  

Its all give and take. Each part does its own thing, but is affected by the others. It really is more than the sum of its parts. They are pretty easy to design and get to sound good. As long as the ported chamber is in the ballpark area of what it needs to be, the sealed chamber makes it hard to mess up too bad.

 

[46panel 10+ year member]

This is what I know:

• Sealed chamber determines power handling, somewhat response.
  
• Ported chamber determines efficiency, also has to do with how steep the cutoffs are.
  
• Bigger the port, the better, to an extent. Anywhere up to around 30in^ of port per cubic foot of ported airspace works great for SPL and setups where you are looking for good numbers. Less control of cone.
  
• Smaller the port, the more gradual the roll off points, but with less efficiency.
  
• Basically I try for a roughly sized sealed chamber, and then build the ported chamber as big as possible usually. Can be different based on the subs or the desired sound, but Ive done some pretty crazy ratios, like 1:4-1:5 and they always sounded great with a nice peak right where I wanted it.
  

Its all give and take. Each part does its own thing, but is affected by the others. It really is more than the sum of its parts. They are pretty easy to design and get to sound good. As long as the ported chamber is in the ballpark area of what it needs to be, the sealed chamber makes it hard to mess up too bad.

Pretty helpful info there. Galatic also told me before about 2 cubes sealed per 18" but dunno about other sizes. I'm probably going to try one with 6 cubes sealed after displacement for my 3 18's and then about 14 cubes ported with about 300" of port area. Also I've heard that you don't want to tune it as low like you would with a regular ported box.

 

[galacticmonkey 5,000+ posts]

For a good musical range, tune to 45-50hz.

Just play around with them.

 

[the Answer 10+ year member]

thank you galactic, and i know that u dont tune as low, i like 27-33 for ported, but yeah i was thinking like 40-45 but 45-50 will be better. thanks

anybody else?

 

[RAM_Designs 5,000+ posts]

Gmonk pretty much nailed it. Smaller ratios work fine too, just not as much output.