Hmmm questions on dividing ports to raise tuning

[vehementSPL 10+ year member]

There was something I was playing around with in WINISD and it shows me if you take the exact same port area and divide it into two ports it raises the tuning. So same total port area . so take 400 inches and put it in one port vs 2 200 inch ports. WinISD shows the tuning to raise considerably. I am like cool. Put a port divider and raise tuning. Problem is this 4th order peaks NO where near as high as it shows. Then when I look at the graph with the full amount of port 400inches. it follows that graph pretty close. This box has 400 inches of port and the port is 3.5 inches deep. Without a divider in it is tuned to around 47ish . Any ideas on how to get the tuning up. Or is there some sort of odd rule as where there has to be a certain amount of distance between the two ports of it to react as two separates and raise the tuning

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[vehementSPL 10+ year member]

That distance thing doesn't make any sense to me. I am just moderately confused

 

[audioarsonal 10+ year member]

If you want to raise tuning try shrinking the port instead of dividing it.With only 3.5" of depth I don't thik adding a baffle to seperate the port will affect tuning as much as WIN is predicting.The program is alright and gives you a base to go on however it isn't always accurate in real world situations.

 

[mrogowski 5,000+ posts]

Your plan will not work since you are not changing the length of your port(s) to compensate. You are in fact, lowering the tuning by increasing the number of ports in your box.

 

[vehementSPL 10+ year member]

If you want to raise tuning try shrinking the port instead of dividing it.With only 3.5" of depth I don't thik adding a baffle to seperate the port will affect tuning as much as WIN is predicting.The program is alright and gives you a base to go on however it isn't always accurate in real world situations.

Shrinking the port lowers tune. increasing port raises

 

[audioholic 5,000+ posts]

Im no box expert, but the same length and port area should equal the same tuning I think. It would, in theory, provide the same resistnce to cone motion and air flow, which essentially is what creates port 'tuning'.

 

[vehementSPL 10+ year member]

Im no box expert, but the same length and port area should equal the same tuning I think. It would, in theory, provide the same resistnce to cone motion and air flow, which essentially is what creates port 'tuning'.

yeah that is what I had always thought. But winISD and bass box pro shows this change in tuning when you do this.

 

[audioholic 5,000+ posts]

yeah that is what I had always thought. But winISD and bass box pro shows this change in tuning when you do this.

This I cant explain. And I dont have either program installed currently to verify.

 

[Buck 5,000+ posts]

Your plan will not work since you are not changing the length of your port(s) to compensate. You are in fact, lowering the tuning by increasing the number of ports in your box.

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