Trying to understand a particular box design

[bcarpenterfhl 10+ year member]

just because he can build boxes, doesnt mean crap about his design/math. i work at a car audio shop, and the people there build absolutely amazing boxes, but they no sh!t when it comes to the proper calculations and physics of a box.

 

[tRiGgEr 5,000+ posts]

You wont have to worry about it for a daily bumper. If your going to be building a comp/show box worry about it.

 

[Goldtaz1 10+ year member]

just because he can build boxes, doesnt mean crap about his design/math. i work at a car audio shop, and the people there build absolutely amazing boxes, but they no sh!t when it comes to the proper calculations and physics of a box.

I was not saying that because he works at a car audio shop he automatically knows how to do calculations/math. I just find it highly improbable that he would not know that the waves would AUTOMATICALLY die in the enclosure upon the crash effect illustrated by Jmac due to his lengthy experience in the car audio industry. When Jmac posed the question about seeing a problem with his diagram, I did see the problem, however I would just think that the waves would continue to move through the rest of the port even though they are crashing into one another.

 

[bcarpenterfhl 10+ year member]

A lot of people won't make the divider visible with this type of design, also ...

how does one conceal the divider?

 

[Goldtaz1 10+ year member]

Make the divider shorter and paint the port black ...

How much shorter could you make the divider?? Just to the point that it doesn't allow the waves to collide??

 

[jellyfish420 10+ year member]

Basically ...
Once the waves are both going in the same direction, they won't cancel each other out ...

so the divider would only have to be 1.5" long?

 

[DBfan187 5,000+ posts]

Well fuck me sideways! I've built several boxes this way and the sound awesome, but I've never did the divider thingy.//content.invisioncic.com/y282845/emoticons/censored.gif.f9ad8e7c6db58c5530c5a0a20a3b5baf.gif

 

[Goldtaz1 10+ year member]

so the divider would only have to be 1.5" long?

I will assume this comment is correct?? You could maybe add another inch just to be on the safe side of things.

 

[SPL140.2 5,000+ posts]

Thats why I like to build boxes with the port on the corner of the enclosure, as mentioned above the sound waves collide with each other before heading out of the port, (loss of energy) //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif , I dont know I have found it to be louder though.

 

[Goldtaz1 10+ year member]

Thats why I like to build boxes with the port on the corner of the enclosure, as mentioned above the sound waves collide with each other before heading out of the port, (loss of energy) //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif , I dont know I have found it to be louder though.

What have you found to be louder? The port in the corner or doing it the way I am looking to build it?

 

[chubby 10+ year member]

least obtrusive

 

[Goldtaz1 10+ year member]

least obtrusive

Cool, but I still fail to understand why it is necessary to put that in there.

 

[req 5,000+ posts]

or you could make a flat fiberglass piece thats like 1\8" thick and use the design jellyfish did, but the BACK port width has to be HALF the center port width.

duh.

 

[Exaran 10+ year member]

Wait a minute guys, If the subs are wired to the same phase, why would the waves be outta phase in the port?!

Say both speakers pull back at the same time, this compresses the air in the box momentarily, and sends a high pressure wave down the ports.... both high pressure waves would hit in the center port at the same time, and COMBINE to a wave with a higher amplitude or power. You dont have cancelation unless a high pressure wave and a low pressure wave hit each other...

 

[Raven 10+ year member]

Well, that's the argument. JMac says the waves will cancel each other out. Others say the wave will combine. Right now, noone on this board has the technology to figure it out.

You'd basically have to trace the air pressure wave from the sub to the intersection and out the port. Even then, you're going to find that different frequencies will have different amounts of cancellation.

My theory: It'll work, but now you're looking at a second tuning frequency based on the width of that port. I have no idea how long a 30hz wave is opposed to a 60hz wave, so you're on your own there.

That's a box tuned to 30hz grand with a 53hz bend for that extra kick. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif