Ported Box for Eight Sony 10'' Woofers?

Ok heres the deal. I am building an enclosure for 8 sony explode 10's. I know they arent jl or even close but I paid $20 per sub and they are brand new so I am going to run them. No back to the questions.  I never ran a ported box. So building one of these is going to be new. Here are the woofer specs.

vb-1.3 cu. ft

f3-28hz

fb-29.6hz

port-3"x11-5/16

I used the port calculator and it told me to run a 14.53 inch port length(3x14.53). Now my first question is, why would the port calculator on here show a different number than sony's information sheet? Next question, Say I fire all the subs up tward the cab of the truck. I plan on running the ports on the same plane as the woofers. Do I have to run each woofer in a seperate enclosure with a seprate port? Or can I run say 4 woofers in the same chamber sharing the same ports as well as the other 4 subs? The truck is a 2002 yukon denali. Any help is appreciated;)

Thanks,michael

Great, the path to take here is fairly simple yet intricate at the same time. I would do this as 4 separate boxes. Each pair of subs share a common chamber. The boxes are going to need to be very well braced. For ease of construction they should be all the same. For ease of installation, 4 boxes are highly easy to move around. They will all need to be bolted together securely both to each other and the vehicle.

Configure your box design program for a box with 2 subs and ported and see what resuslts come out of it.

Thanks for the reply rob;)  that sounds simple enough. So Each box will have 2 ports? What about the port length? I am still a little confused about that........

Michael

With two subs sharing the same chamber, you would figure one port per chamber.  Port size is determined on an individual basis:  take into consideration how much room you have to work with, for one, and the minimum port diameter and required length will change from one setup to the next depending on woofer parameters.  One program will figure slightly different than another just like one person will figure it slightly different than another person.  The principle of venting is:  the driver's excursion has to be damped so that it doesn't just flap wildly.  A vented box is open to the outside air.  A port contains a volume of air that has restrictions, and that is the port diameter.  The diameter of the port will allow only a quantifiable amount of air to be expelled at a time.

The program you use will take the driver's T/S parameters into consideration along with the total air space in the chamber.  A vented box will allow the driver to push frequencies above the driver's resonant frequency as long as the port is correctly designed.  But the lower frequencies will be damped by the port air volume to contain the movement of the cone.  The slightest change in port diameter, such as making it larger, will allow freer air flow...so the overall port volumt has to become larger.  A smaller diameter restricts the air flow, so the port volume is less.  An important consideration that has to be made is the noise of air being expelled from a port hole:  too small an opening would create air noise.  That is where trade-offs are made, and in every case there is a trade-off.

You have a finite amount of space to work with in a vehicle, and the more gear you use the more space that is required.  That restiction of space also restricts the space you can give up to port sizes.  So, as Rob suggested, figure your program to vent two subs in one chamber and see what you come up with for one of the four boxes.  Then post your results.

stevdart wrote:

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With two subs sharing the same chamber, you would figure one port per chamber.  Port size is determined on an individual basis:  take into consideration how much room you have to work with, for one, and the minimum port diameter and required length will change from one setup to the next depending on woofer parameters.  One program will figure slightly different than another just like one person will figure it slightly different than another person.  The principle of venting is:  the driver's excursion has to be damped so that it doesn't just flap wildly.  A vented box is open to the outside air.  A port contains a volume of air that has restrictions, and that is the port diameter.  The diameter of the port will allow only a quantifiable amount of air to be expelled at a time.

The program you use will take the driver's T/S parameters into consideration along with the total air space in the chamber.  A vented box will allow the driver to push frequencies above the driver's resonant frequency as long as the port is correctly designed.  But the lower frequencies will be damped by the port air volume to contain the movement of the cone.  The slightest change in port diameter, such as making it larger, will allow freer air flow...so the overall port volumt has to become larger.  A smaller diameter restricts the air flow, so the port volume is less.  An important consideration that has to be made is the noise of air being expelled from a port hole:  too small an opening would create air noise.  That is where trade-offs are made, and in every case there is a trade-off.

You have a finite amount of space to work with in a vehicle, and the more gear you use the more space that is required.  That restiction of space also restricts the space you can give up to port sizes.  So, as Rob suggested, figure your program to vent two subs in one chamber and see what you come up with for one of the four boxes.  Then post your results.

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Thanks for the info:)That clears things up alot. With that being said, can I run 2 =3"ports for the pair or will the port values change ?

I have to ask first, are you using port design software to help with this?  Because if you are, you would see the changes in port length that come with doubling the port diameter.  Use a program (I use WinISD Pro beta, which is available free), or get familiar with the complicated calculations necessary to get venting right.  A couple of links, the first is a download link for WinISD Pro, the second a page of individual links, many of which will show calculations and some with calculators.

https://www.linearteam.dk/default.aspx?download=winisdpro

https://www.carstereo.com/help2/Articles.cfm

...and you must not have read my sig line...