Thoughts on ported design

[toybox]

I am looking at a design for a c-pillar wall in a small SUV. I started looking at the idea of a 4th order but ended with a ported I like where the 2x 15s point up from the box, then the port extends out of the box to wrap over the top of the subs. The bottom area is about 7 ft cu and the area above the subs is about 4 ft cu with the port being 3 inch slot all the way across box and ported about 32hz.

My main concern here is that this area the subs are firing into - will that cause issues with freq cancellation or try to act like a port that is not tuned? Trying to get okay SQ while focusing on decent SPL output (loud listening SPL not metered for comp SPL)

Thoughts?

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[RobGMN 5,000+ posts]

I am looking at a design for a c-pillar wall in a small SUV. I started looking at the idea of a 4th order but ended with a ported I like where the 2x 15s point up from the box, then the port extends out of the box to wrap over the top of the subs. The bottom area is about 7 ft cu and the area above the subs is about 4 ft cu with the port being 3 inch slot all the way across box and ported about 32hz.

My main concern here is that this area the subs are firing into - will that cause issues with freq cancellation or try to act like a port that is not tuned? Trying to get okay SQ while focusing on decent SPL output (loud listening SPL not metered for comp SPL)

Thoughts?

Can you provide some dimensions and maybe a better drawing of your idea? If the "slot" that the woofer is firing into is too narrow, you can indeed run into some issues.

 

[toybox]

overall the box would run about 40in wide x 30 in tall x 26 in deep with the port being the 40 wide and 3 tall at 32 ish length. I did already mod dimensions for 2 layers wood and sub displacement. it leaves this top area about 40 wide x 12 tall x 22 deep approx. I have all the exact specs mapped out but easier to speak in approx.

I have also come to learn about this creating "loading wall" that I can tune via a 1/4 wave calc but it seems at the moment that this would create a 140hz tune that would be rather useless - if I am understanding that proper.

 

[Bobbytwonames 5,000+ posts]

overall the box would run about 40in wide x 30 in tall x 26 in deep with the port being the 40 wide and 3 tall at 32 ish length. I did already mod dimensions for 2 layers wood and sub displacement. it leaves this top area about 40 wide x 12 tall x 22 deep approx. I have all the exact specs mapped out but easier to speak in approx.

I have also come to learn about this creating "loading wall" that I can tune via a 1/4 wave calc but it seems at the moment that this would create a 140hz tune that would be rather useless - if I am understanding that proper.

What vehicle? Just make the box taller and put the port back inside the box at the bottom of the box IMO.

 

[toybox]

@Bobbytwonames it is going into a 2005 highlander. the reason I was trying the port up high was that i wanted to do a c-pillar wall and have that port shooting forward over the back seats.

that said, i think i am just going to try a series 6th order bandpass, internal tuned to 32 and external tuned at 55 with a 1:1 size ratio

 

[Buck 5,000+ posts]

If you could, I’d fire the port into the chamber that the sub is firing into. I would just make sure the cross sectional opening there is more than the Sd area of the subs.

 

[Bobbytwonames 5,000+ posts]

@Bobbytwonames it is going into a 2005 highlander. the reason I was trying the port up high was that i wanted to do a c-pillar wall and have that port shooting forward over the back seats.

that said, i think i am just going to try a series 6th order bandpass, internal tuned to 32 and external tuned at 55 with a 1:1 size ratio

Why so high? Why not 25 and 45?

 

[winkychevelle 10+ year member]

To me that looks like a poorly designed parallel 6th order