Port walls?

[PV Audio 5,000+ posts]

Get rid of the two chambers and use one large chamber instead. The only advantage to using separate chambers is to get some free bracing out of the port walls.

 

[gtbike900 10+ year member]

Port length kills deebeez man.

how does port length kill dbs

 

[Caleb9107 10+ year member]

The only reason I am doing two chambers is because I like the look of two kerfs on my box. It was either two in the middle or on the sides so I chose the middle. Should I try to use a common air space with a kerf on either side?

 

[DNick454 10+ year member]

The only reason I am doing two chambers is because I like the look of two kerfs on my box. It was either two in the middle or on the sides so I chose the middle. Should I try to use a common air space with a kerf on either side?

Looks doesn't = sounding good //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

It's more efficient (and much easier to construct to boot) to use a common chamber. 4 cubic feet with atleast 50 sq in of port area tuned to your liking should do great. I wouldn't bother trying to make two ports. That always bothered me at first too. I wanted my box to be symmetrical and whatnot. Truth is, it doesn't matter, and it's better to stick with one large port. Less room for error and easier to build and build correctly.

 

[PV Audio 5,000+ posts]

The only reason I am doing two chambers is because I like the look of two kerfs on my box. It was either two in the middle or on the sides so I chose the middle. Should I try to use a common air space with a kerf on either side?

Well I like the sound of a proper enclosure to my ears. I suggest that you take the time to design the enclosure properly instead of worry about how your kerfs look.

 

[Caleb9107 10+ year member]

Looks doesn't = sounding good //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
It's more efficient (and much easier to construct to boot) to use a common chamber. 4 cubic feet with atleast 50 sq in of port area tuned to your liking should do great. I wouldn't bother trying to make two ports. That always bothered me at first too. I wanted my box to be symmetrical and whatnot. Truth is, it doesn't matter, and it's better to stick with one large port. Less room for error and easier to build and build correctly.

Understandable =] haha. I just know that I want my box to have kerfs. I am not a big fan of the solo giant port on one side.. Building the box shouldn't be much of a problem..

Question: If I end up designing it with a common chamber and 2 ports, would I just tune each one to my desired 34 hz or does having two require some crazy tuning to equal my box playing at 34 hz?

 

[DNick454 10+ year member]

Understandable =] haha. I just know that I want my box to have kerfs. I am not a big fan of the solo giant port on one side.. Building the box shouldn't be much of a problem..
Question: If I end up designing it with a common chamber and 2 ports, would I just tune each one to my desired 34 hz or does having two require some crazy tuning to equal my box playing at 34 hz?

Lets say a 4" wide port 17" tall that is 30 inches long = X tuning frequency. Having two ports would be two 2" wide ports 17" tall that are both 30" long. But keep in mind, you're using more wood to make more port walls which takes up more internal volume and throws up the tuning a tad bit.

The reason the port to one side is such a sought after design is its efficiency of space. Just think about it... The bottom of the box, top of the box, side, and back walls all act as parts of the port. you only need to add one or two pieces to complete all FOUR walls of the port. This saves internal space in the box that would be wasted by having to construct all the port walls in addition to the box walls. Other than using aero ports, a single slot port that folds along the box's perimeter is simply the most effective use of space as well as wood.

 

[PV Audio 5,000+ posts]

Understandable =] haha. I just know that I want my box to have kerfs. I am not a big fan of the solo giant port on one side.. Building the box shouldn't be much of a problem..
Question: If I end up designing it with a common chamber and 2 ports, would I just tune each one to my desired 34 hz or does having two require some crazy tuning to equal my box playing at 34 hz?

This is a stupid idea and has no reason to be done at all. You're just going to end up complicating everything when it doesn't need to be done, so just use one large port instead.

 

[PV Audio 5,000+ posts]

Lets say a 4" wide port 17" tall that is 30 inches long = X tuning frequency. Having two ports would be two 2" wide ports 17" tall that are both 30" long. But keep in mind, you're using more wood to make more port walls which takes up more internal volume and throws up the tuning a tad bit.
The reason the port to one side is such a sought after design is its efficiency of space. Just think about it... The bottom of the box, top of the box, side, and back walls all act as parts of the port. you only need to add one or two pieces to complete all FOUR walls of the port. This saves internal space in the box that would be wasted by having to construct all the port walls in addition to the box walls. Other than using aero ports, a single slot port that folds along the box's perimeter is simply the most effective use of space as well as wood.

Close, but this isn't entirely right. Since I'm studying for an exam and don't have time to explain, so just go with one port as the rest of the post says. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[DNick454 10+ year member]

Close, but this isn't entirely right. Since I'm studying for an exam and don't have time to explain, so just go with one port as the rest of the post says. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

I know it isn't "exactly" right, and it's because of surface area. Two ports have more surface area than a single port with the same area+length. The increased surface area that the air travels past creates more drag and yadda yadda. No need to explain //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

I was just giving him a rough idea. Best bet is to stick with a single port.

 

[sub-FATHER 10+ year member]

So what would you suggest to get a lower tuning? I believe 38 is too high? Am I correct in thinking this? My goal was about 34 hz. This is a daily driver that I would just like to hit the lows.. I am not aiming for any numbers or competing in any way.

the longer the port the deeper the bass.

 

[Caleb9107 10+ year member]

Hmm.. Thanks for the input.. Now i just have to figure out what I wanna do in my design! I'll post up the look and see what people think when I design it!

 

[sub-FATHER 10+ year member]

how does port length kill dbs

it lowers the frequency, and the lower the frequency the more power it takes to produce the same spl of a higher frequency with the same amount of power. but if its your daily driver make your port length longer

 

[DNick454 10+ year member]

the longer the port the deeper the bass.

To an extent... There's a point of diminishing returns where you can keep adding tons of port length and the tuning only goes down a very miniscule amount. This is because of the volume inside the box that the port takes up. As the port gets longer, the tuning lowers but internal volume is also taken up which tries to raise the tuning and at a certain point they will almost offset eachother.

 

[sub-FATHER 10+ year member]

Lets say a 4" wide port 17" tall that is 30 inches long = X tuning frequency. Having two ports would be two 2" wide ports 17" tall that are both 30" long.

you better research that somemore, your giving wrong information on that one bud. you cant just cut the port from 4" to 2" and expect the length to stay the same especially when your cutting the airspace of the enclosure in 1/2 when you calcuate that one.