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1two3

thoughts on my first ported box design

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never designed a ported box before so feel free to give any critisism/help

 

for an xcon 10"

net box volume 1.37 cubes

port length 31.05" 

diameter: 1.75"

 

if anyone is so inclined feel free to double check calculations and such as ive never done this before and might have done something wrong 

 

all info should be in pics bellow

 

portlengthcalc_zpsd61f60a8.jpg

 

myboxdesign_zps5a0ff170.jpg

 

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Just occurred to me that the optimal enclosure volume for the xcon is 1.5-1.75 cubes. The predesigned enclosures offered for the xcon are 1.1 cubes and 1.35 which happens to be the exact same as the icon designs. Perhaps Aaron or someone Could chime in on this/confirm that it would be better to make my box 1.75cubes rather than 1.35'

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Yea depending on the power your running I would go a bit larger also

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That enclosure is also only 1.37 NET not counting the displacement of the sub at .15cuft.  The total enclosure NET volume after the sub is installed will only be 1.22 cuft which falls just short of the recommended minimum FWIW.

 

 

Are those dimensions the largest you can physically fit in the space you have?  If not then it wouldn't hurt to try to get a little larger volume and possibly even a little more port area.  To be sure you don't have to worry about port noise being an issue you should have in the neighborhood of 40 sq.in. of port area for the sub.

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Yea depending on the power your running I would go a bit larger also

 

around 1200rms.  

 

 

That enclosure is also only 1.37 NET not counting the displacement of the sub at .15cuft.  The total enclosure NET volume after the sub is installed will only be 1.22 cuft which falls just short of the recommended minimum FWIW.

 

 

Are those dimensions the largest you can physically fit in the space you have?  If not then it wouldn't hurt to try to get a little larger volume and possibly even a little more port area.  To be sure you don't have to worry about port noise being an issue you should have in the neighborhood of 40 sq.in. of port area for the sub.

 

i recalculated and u are in fact correct. i got 1.31627 cubes net with everything subtracted (first time i think i added some)

 

no i can deffinatly do bigger, its going in an SUV ill sketch up another one this weekend and hopefully fix these issues.  is there a calculator for port area or is this a rule of thumb?

Edited by 1two3

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It's definitely not a rule of thumb.  The best calculator for port area was put up and made by a member on here, however I won't use the site anymore as it has numerous warnings from Chrome and my Anti-Virus/Malware/Spyware scanners telling me the site is a problem.  The one on Carstereo.com is better than nothing or if you're not shy about doing some math the actual T/S formulas are out there.  I tried doing a search and couldn't find anything but simple calculators, not nearly as accurate at the one that I can't use anymore, lol.

 

 

EDIT: Found the actual formula's HERE.  The formula's calculate minimum diameter in centimeters.  A little more math and you can convert it to inches, then figure the cross sectional area to know what size the slot needs to be.  Again, got to not be shy about the math, lol.

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thank you for those links, Alton!

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It's definitely not a rule of thumb.  The best calculator for port area was put up and made by a member on here, however I won't use the site anymore as it has numerous warnings from Chrome and my Anti-Virus/Malware/Spyware scanners telling me the site is a problem.  The one on Carstereo.com is better than nothing or if you're not shy about doing some math the actual T/S formulas are out there.  I tried doing a search and couldn't find anything but simple calculators, not nearly as accurate at the one that I can't use anymore, lol.

 

 

EDIT: Found the actual formula's HERE.  The formula's calculate minimum diameter in centimeters.  A little more math and you can convert it to inches, then figure the cross sectional area to know what size the slot needs to be.  Again, got to not be shy about the math, lol.

 

 

k so i got through most of it but im lost at the cross sectional area part.  i got all the other calculations (how correct they are im not sure) but i just dont understand what to do with it/what it measures

 

my calculated Dmin (minimum port diameter) came out to 30.8cm

ill qoute wich part makes no sence to me:

 

"Slot Ports

If you wish to use a slot port, first determine the diameter of a round port that has the same cross-sectional area as the slot. The following equation can be used to do this:

    Dv' = 2*((W*H)/pi)^0.5

where,

  Dv' =  diameter of equivalent round port

  W = width of slot

   H = height of slot

Once you've calculated Dv', you can use it in the equation for Lv above to determine the required length of the slot port to tune the enclosure to the required frequency (Fb)."

 

does that mean figure out what daimeter the port will be going through the hypotenuese [/] or accross [-] the port

Edited by 1two3

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I'd make the box a bit larger, and would make the port a bit wider than 1.75, the less ratio of h:w the better. You could also give an aeroport a shot, it'll be a bit more costly than building a slot, but much easier since all you have to do is cut a hole in the box. It'd be pretty easy to do it side firing as long as you have clearance, or firing out of the baffle if you used an elbow piece. It would also be a good deal easier to calculate tuning.

For reference, I'll be running a 4" aero in my build for 2 8s (slightly more cone area than 1 10") on 1.5k in about 1.75cubes

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I'd make the box a bit larger, and would make the port a bit wider than 1.75, the less ratio of h:w the better. You could also give an aeroport a shot, it'll be a bit more costly than building a slot, but much easier since all you have to do is cut a hole in the box. It'd be pretty easy to do it side firing as long as you have clearance, or firing out of the baffle if you used an elbow piece. It would also be a good deal easier to calculate tuning.

For reference, I'll be running a 4" aero in my build for 2 8s (slightly more cone area than 1 10") on 1.5k in about 1.75cubes

Yea I was considering a an aero but probably just straight PVC no flares. How do u figure out what size pipe to use?

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Why no flares? They make the port even more efficient, can reduce chuffing etc.

if you don't want to pay for the precision port kit, I would grab a router and make wood flares, basically just router out a ring and rabbet the inside edge so that the PVC fits into it and then epoxy it or fiberglass it on and hit it with a roundover bit on the inside and outsides. . A wooden flare would also make it possible to brace the port just by screwing the flare to the box.

The size of port you want to use depends on your goals, the woofer and the size of the enclosure. If I was you, I'd go for a 5" or 6". I'll find the tuning formula for aeros.

Edited by sexterra

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The size or port surface area has nothing to do with "what you are trying to do". There are only three things that dictate port area

1. Driver sd

2. Driver Xmax

3. Enclosure tuning

Number 1 and 3 are easy. Good luck with 2. No one gives a Xmax rating that is associated with Richard Small's minimum port area formula. Xmax is defined as coil overhang, not the rating published by most.

99.999% PVC ports won't work unless you are tuning incredibly high or you are using no where enough port area.

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The size or port surface area has nothing to do with "what you are trying to do". There are only three things that dictate port area

1. Driver sd

2. Driver Xmax

3. Enclosure tuning

Number 1 and 3 are easy. Good luck with 2. No one gives a Xmax rating that is associated with Richard Small's minimum port area formula. Xmax is defined as coil overhang, not the rating published by most.

99.999% PVC ports won't work unless you are tuning incredibly high or you are using no where enough port area.

 

Learn something new everyday. What I mean by what hes trying to do is that people who are all about spl generally go for a ridiculous amount of port.

 

Id be interested to see how my port area will be for my box, I could probably get the actual xmax spec from PSI for my subs.

 

If the pvc ones arent big enough, there are always the concrete tubes, or you can build an octoport.

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The area of the port isn't the issue. Any driver with at least 20mm of coil overhang utalizing proper port area will need a port in excess of 30 inches long.

I know how to go about creating nearly unlimited port length with a round port without using elbows or bends but the average Joe or even these so called box designers don't know how to.

And FYI if a so called designer wants to build you a octagon shaped port run far away as quick as possible. It's either tuned to 50 hertz or it's only about 25 percent of the nessecary port area needed for the system. There is no way a 30 to 50 inch long port of that nature will fit in typical box. Unless they know what I know and even if they do they would be impeding on proprietary patented information.

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The area of the port isn't the issue. Any driver with at least 20mm of coil overhang utalizing proper port area will need a port in excess of 30 inches long.

I know how to go about creating nearly unlimited port length with a round port without using elbows or bends but the average Joe or even these so called box designers don't know how to.

And FYI if a so called designer wants to build you a octagon shaped port run far away as quick as possible. It's either tuned to 50 hertz or it's only about 25 percent of the nessecary port area needed for the system. There is no way a 30 to 50 inch long port of that nature will fit in typical box. Unless they know what I know and even if they do they would be impeding on proprietary patented information.

 

Wow, interesting. Alot of this is pretty crazy to me since it basically means everyone is doing it wrong. 

 

Are there any articles/literature I could read to understand how this all works? 

 

And I'm assuming that means that my hopes of getting an explanation on how to do that are unreasonable? 

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For proper enclosure design get a copy of loudspeaker cookbook.

Even if I showed how it's done it's illegal to use even for personal purposes with out the patentee's consent.

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For proper enclosure design get a copy of loudspeaker cookbook.

Even if I showed how it's done it's illegal to use even for personal purposes with out the patentee's consent.

I'll check that out.

Patent no.?

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well this sucks. the more i look/ask around the more i hear thats wrong, dont do that.  it seems that all info floating around is either misconception or just plain false.

 

is there any one that can either help me design a proper ported box or link me to some actual reliable resource so i can figure out how to do it myself?

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well this sucks. the more i look/ask around the more i hear thats wrong, dont do that. it seems that all info floating around is either misconception or just plain false.

is there any one that can either help me design a proper ported box or link me to some actual reliable resource so i can figure out how to do it myself?

That's why I don't ask questions on here. People are plenty happy to shoot ideas down without offering anything constructive. It's never gotten me anywhere.

Check out the speaker cook book. It's got good stuff in it but I think it's a little more than what you are looking for at this point in time. I read a little of it. It's pretty good. I think most of what Quentin was talking about was trying to get a perfectly flat response.

You would be fine with a 6" aeroport IMO.

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well this sucks. the more i look/ask around the more i hear thats wrong, dont do that. it seems that all info floating around is either misconception or just plain false.

is there any one that can either help me design a proper ported box or link me to some actual reliable resource so i can figure out how to do it myself?

That's why I don't ask questions on here. People are plenty happy to shoot ideas down without offering anything constructive. It's never gotten me anywhere.

Check out the speaker cook book. It's got good stuff in it but I think it's a little more than what you are looking for at this point in time. I read a little of it. It's pretty good. I think most of what Quentin was talking about was trying to get a perfectly flat response.

You would be fine with a 6" aeroport IMO.

 

Regardless of someone's apparent lack of knowledge in an area, people are quick to make sure that person knows that it's a dumb idea, and nothing more. Not what's wrong with it, not why, nothing. Just that OP is stupid. Makes the forum pretty irritating sometimes, especially considering that MOST of what I learn comes off this board, at least so far. 

Edited by SpeakerBoy

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There is no spoon fed answer that works. EVERYTHING is a compromise. If you find an answer elsewhere where they don't take into account information regarding your constraints it'll be even worse than what you designed.

Port area isn't so tough. What is tough is understanding how sensitive you are to chuffing and if you care about tenths. Once you get beyond that just design it so that there is a reasonable mach. Only way to find out your ears sensitivity to chuffing is to build something and see. Plenty of rules of thumbs but like all of them they are wrong for the majority of situations.

The best thing you can do is build the recommended enclosure on the site for your sub. Tell us what you like and don't like about it and then build another that solves those concerns. Getting a subjective opinion on the best layout for something without any background is uber useless.

They are also good designs to learn what works and doesn't.

You can tell how bad other forums are at representing what is good. The number of 4th order BP, T-line, Octoport, and so on enclosures that get recommended is stupid. I've yet to see a single one of them done in a way that would even be as good as the standard boring manufacturers recommended ported enclosure. So, if you go anywhere and they recommend ANY of those, run like hell.

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well said ///M5. ive tried some of those boxes in previous builds. trying to be different but when it came down to it. a simple built to spec slot port or aero port box worked better than any fancy crap did. keep it simple OP. its way easier with better results

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well this sucks. the more i look/ask around the more i hear thats wrong, dont do that. it seems that all info floating around is either misconception or just plain false.

is there any one that can either help me design a proper ported box or link me to some actual reliable resource so i can figure out how to do it myself?

That's why I don't ask questions on here. People are plenty happy to shoot ideas down without offering anything constructive. It's never gotten me anywhere.

Check out the speaker cook book. It's got good stuff in it but I think it's a little more than what you are looking for at this point in time. I read a little of it. It's pretty good. I think most of what Quentin was talking about was trying to get a perfectly flat response.

You would be fine with a 6" aeroport IMO.

No where in any of my post were there anything remotely involving response. Only thing I talked about is port area. Vehicles have transfer function therefore you do NOT want to build a system with a flat response.

I don't give out links to calculators because they are worthless to anyone who doesn't understand the basic physics behind enclosure design. But a copy of the cookbook. They come back with specific questions and we will be happy to help.

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Deleted

Edited by garychurch84

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That's probably the most shamefull thing I've seen in a while. I'll remember to give him a call after lunch to inform him of the piracy. Although he's humble enough he probably won't even worry about it. That man's involvement in the industry is why 95% of the product on the market is out there. I find it pathetic people can justify stealing decades of knowledge like that.

Mark, Aaron, or a mod needs to remove that link from SSA.

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