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Silver Member Username: Dmm2005DD Audio ORION, Warren Count... USA Post Number: 429 Registered: Aug-06 | im building a box for my friend's 9515 and its gonna be 4.5 net cubes and tuned to 32 hz. How do you decide what port area to do for ports. Im gonna run one big square port on there or does it matter how big you go on them? |
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Bronze Member Username: Nickb4247Post Number: 13 Registered: Dec-06 | Well the surface area of the port is directly related to the lenght of the port. The longer the port is proportional to is surface area the lower the box with be tuned. You want the surface area of the port to be large enough to avoid port noice at high volumes, but you want it small enough to controll the ecursion of the sub. To large of a port might make the sub "unload"(freeair). |
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Silver Member Username: Dmm2005DD Audio ORION, Warren Count... USA Post Number: 430 Registered: Aug-06 | oh ok...ive got the equation for port legnth but i am not sure how to pick port area to optimize it, after that i can tune it, or would you just go like the equilivent area of some aero ports. |
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Bronze Member Username: Nickb4247Post Number: 22 Registered: Dec-06 | I am just guessing, but I wouldn't make the port area smaller then 140sqin. |
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Gold Member Username: Logan__tille[:-]15 Wangers Club[:-] Premier Member Post Number: 4679 Registered: Feb-06 | ^^^^WTF are you talking about? thats like half the box. |
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Silver Member Username: Phil_salisburyPost Number: 139 Registered: Sep-06 | 140 sq.in. of port area, yeah, do that an you'll need a d@mn box twice it's size for port tuned at 32hz. Best way to determine if your port area is enough is to find a calculator that will provide info related to the max power applied given the volume, port tuning and port area so it will give you the vent mach of that port. You want keep the vent mach around 75 ft/sec. |
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Silver Member Username: Dmm2005DD Audio ORION, Warren Count... USA Post Number: 433 Registered: Aug-06 | Does this look right to you? http://www.carstereo.com/help/Articles.cfm?id=4 |
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Silver Member Username: Dmm2005DD Audio ORION, Warren Count... USA Post Number: 434 Registered: Aug-06 | and is reference efficiency the SPL 1w/1m number? I cant find that. |
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Silver Member Username: Dmm2005DD Audio ORION, Warren Count... USA Post Number: 445 Registered: Aug-06 | I cant get the equation i found to work out right for me...it is sayin to get the right speed i need the radius would have to be under 2" which is way too small for a 9515 |
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Silver Member Username: Phil_salisburyPost Number: 140 Registered: Sep-06 | Bag that calculator, it sucks azz wind. Use this one: http://www.linearteam.dk/default.aspx?pageid=ventcalculator |
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Silver Member Username: Phil_salisburyPost Number: 141 Registered: Sep-06 | In addition to what I just posted for the calculator since the port size is based on round port size. Use this calculator to determine your port diameter: http://www.math.com/students/calculators/source/circle-solver.htm Input the SQ. IN. you want for the port, it will convert that to a round port diameter and use that diameter to input into the other calculator for the port size. |
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Gold Member Username: SouthernrebelMonroe, Louisiana DD 9515d~~]... Post Number: 4039 Registered: Mar-04 | A good rule of thumb is at 12sq inches of port per net cuft in lower power situations. But for higher power...try 15sqin+ per cuft. For that 9515 in 4.5cuft, i would go w/ 75sq inches of port ~31" long. That will tune the box to ~34hz on paper....That would sound great. |
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Bronze Member Username: Nickb4247Post Number: 31 Registered: Dec-06 | Opps, I F%$# up. Divide what I said by 2. |