Question About Aeros

[holley2346 6]

I am using the following tool to figure out how long my aeros need to be to tune the box.

http://psp-inc.com/tools.html

It will be a ~5 ft^3 box

I want to tune it to ~29 hz

I am going to use 6" aeros http://www.parts-express.com/pe/showdetl.cfm?Partnumber=268-354

I want to use 4 of them, for the look it will give the box.

What I'm wondering is after I put all this in the calculator, it tells me I need 69" of length. Is this per aero or all of them combined? I would hope that it would be inches total and not per aero.

Thanks

[Zach Gates 0]

Per port. Four six inch aeros on such a small box would require INSANE port length to get the tuning right. Two would be plenty.

[XxedgarxX 2]

this is what i learned yesterday

you divide the final space of box (5cf) by the number of aeros you want to use (4)

which is 1.25cf for every aero to get the tuning "i use the12volt

and yes is 68 inches per aero

pmybtw

pms dont work

maybe using 2 4" aeros would be enough

Edited August 26, 2009 by XxedgarxX

[Zach Gates 0]

winISD is a heck of a lot faster and makes box-building pretty simple. Punch in the volume and tuning you want, number of ports and diameter, and it'll tell you how long they need to be. Then it's as easy as calculating the volume each port takes up, and figuring out the dimensions the box needs to be minus displacement.

[holley2346 6]

winISD is a heck of a lot faster and makes box-building pretty simple. Punch in the volume and tuning you want, number of ports and diameter, and it'll tell you how long they need to be. Then it's as easy as calculating the volume each port takes up, and figuring out the dimensions the box needs to be minus displacement.

Could you provide me with a template for a BTL 18 for winisd? After entering the parameters it tells me that they don't work out.

Thanks

[Zach Gates 0]

Could you provide me with a template for a BTL 18 for winisd? After entering the parameters it tells me that they don't work out.

Thanks

Ignore all that. For box-building, as long as the company tells you how big to make the box you're set. FI says between 5 and 10, so how big do you want it? After that you can just use whatever initial driver comes up when you do the wizard. The sub in the boxdoesn't change the tuning freq, all the various parameters do is make the graph behind it if you're the advanced type and can use that. So here:

1) Open WinISD, click "new" and then just hit "next". Select 1 driver, then vented box type. Now it should look like this:

2) So go under the "box" tab, put in the volume and tuning you want:

3) Now under the "vents" tab say how many you want and what diameter, in this example two 6" diameter ports:

Now since your box is 5cu, even TWO sixers is way long, so if you just wanted one it would only need to be 13.37" long.

4) Now since we're doing aeros, you can calculate your box's internal volume by doing this:

((W-1.5)*(H-1.5)*(D-1.5)-Vp-Vs))/1728

Side note: 1728 is one cubic foot in inches, which is why we divide by it there.

W = Width of the box in inches (external)

H = Height in inches (external)

D = Depth in inches (external)

Vp = Port volume in inches, which we can ballpark at pi*r^2*L (radius/Length of the port), so 3*3*3.14*14 (again, this is ballparking, it won't alter the tuning THAT much) = 395.64

Vs = Sub volume in inches, 0.26cu for the BTL 18, so 0.28*1728 = 484

So now open up your handy-dandy google or calculator, start throwing numbers in until you get an answer around 5. For example:

(((33 - 1.5) * (20 - 1.5) * (18 - 1.5)) - 395.64 - 484) / 1728 = 5.0554022

Meaning, your box could be 33" wide, 20" tall, and 18" deep with a 6" wide aero 13.5" deep and an 18" BTL sub in it for a 5cu box tuned around 29-30Hz.

Edited August 26, 2009 by Zach Gates

[holley2346 6]

Could you provide me with a template for a BTL 18 for winisd? After entering the parameters it tells me that they don't work out.

Thanks

Ignore all that. For box-building, as long as the company tells you how big to make the box you're set. FI says between 5 and 10, so how big do you want it? After that you can just use whatever initial driver comes up when you do the wizard. The sub in the boxdoesn't change the tuning freq, all the various parameters do is make the graph behind it if you're the advanced type and can use that. So here:

1) Open WinISD, click "new" and then just hit "next". Select 1 driver, then vented box type. Now it should look like this:

2) So go under the "box" tab, put in the volume and tuning you want:

3) Now under the "vents" tab say how many you want and what diameter, in this example two 6" diameter ports:

Now since your box is 5cu, even TWO sixers is way long, so if you just wanted one it would only need to be 13.37" long.

4) Now since we're doing aeros, you can calculate your box's internal volume by doing this:

((W-1.5)*(H-1.5)*(D-1.5)-Vp-Vs))/1728

Side note: 1728 is one cubic foot in inches, which is why we divide by it there.

W = Width of the box in inches (external)

H = Height in inches (external)

D = Depth in inches (external)

Vp = Port volume in inches, which we can ballpark at pi*r^2*L (radius/Length of the port), so 3*3*3.14*14 (again, this is ballparking, it won't alter the tuning THAT much) = 395.64

Vs = Sub volume in inches, 0.26cu for the BTL 18, so 0.28*1728 = 484

So now open up your handy-dandy google or calculator, start throwing numbers in until you get an answer around 5. For example:

(((33 - 1.5) * (20 - 1.5) * (18 - 1.5)) - 395.64 - 484) / 1728 = 5.0554022

Meaning, your box could be 33" wide, 20" tall, and 18" deep with a 6" wide aero 13.5" deep and an 18" BTL sub in it for a 5cu box tuned around 29-30Hz.

Thank you for your help

[shizzzon 461]

winisd may not be able to properly calculate PSP's aero's.

Reason being is winisd doesn't know the outer flare size of the 6" port.

All it knows is the ID is 6" and is round... newer versions of winisd will allow you to choose flared end correction but i do not know how accurate that is based upon multiple ways to make a flare...

I'd just use PSP's calculator since they make em.

[holley2346 6]

winisd may not be able to properly calculate PSP's aero's.

Reason being is winisd doesn't know the outer flare size of the 6" port.

All it knows is the ID is 6" and is round... newer versions of winisd will allow you to choose flared end correction but i do not know how accurate that is based upon multiple ways to make a flare...

I'd just use PSP's calculator since they make em.

That's what I'm using . I wish I could do 2 big aeros . It just looks so good.

I still need to arrange where I am going to put batts/SA3000D/2 powerbass asa800.2's (or 2 soundstream pcx2.700's)/2 horns/6 midbass drivers/ and a 32 band equalizer. And pretty it all up.

If anyone has ANY suggestions, I am open for anything.

Thanks.

Edited August 27, 2009 by holley2346

[shizzzon 461]

you only need 2 6" aeros.

If you were going non flared, you would need up to 80sqin, 2 6" aeros is about 57sqin and is fine.

Typical recommendations-

14-16sqin if non flared per cube

9-12sqin if flared per cube

This works well in real world builds for music.

[holley2346 6]

you only need 2 6" aeros.

If you were going non flared, you would need up to 80sqin, 2 6" aeros is about 57sqin and is fine.

Typical recommendations-

14-16sqin if non flared per cube

9-12sqin if flared per cube

This works well in real world builds for music.

I would have to make them extremely long to tune down to ~29 hz with a 5 ft^3 box though....

[slim2fattycake 85]

wrap around? hehe.

[holley2346 6]

angles would effect flow through the tubes though, wouldn't it?

[Zach Gates 0]

you only need 2 6" aeros.

If you were going non flared, you would need up to 80sqin, 2 6" aeros is about 57sqin and is fine.

Typical recommendations-

14-16sqin if non flared per cube

9-12sqin if flared per cube

This works well in real world builds for music.

Where in the world did you get those numbers? That non-flared number is the same as slot port area recommendations which would be almost IMPOSSIBLE to actually use. If you wanted to make a 4cu box tuned to ~30Hz and used the 16sq per 1cu rule we're talking 56sq of port area, so we'de need either four 4" ports or two sixes, at a length of 34" for the 4" ports or 37 for the 6" ports. EACH.

Just to repeat: according to you we'd need two six-inch diameter ports over three feet long in a box that's only 4cu net anyway. I have never in my life seen a box with aeros use that kind of ratio. It would have to bend TWICE or have at least half of it sticking outside the damn box.

[Zach Gates 0]

angles would effect flow through the tubes though, wouldn't it?

If you get an elbow joint, not so much. The reason it's a problem in slots is the sharp corners muck with the air flow, but with a smooth bend in a pipe it's not as much of an issue. As long as you don't use a joint that comes to a right angle.

[holley2346 6]

angles would effect flow through the tubes though, wouldn't it?

If you get an elbow joint, not so much. The reason it's a problem in slots is the sharp corners muck with the air flow, but with a smooth bend in a pipe it's not as much of an issue. As long as you don't use a joint that comes to a right angle.

I guess I could heat up some pvc and just bend it... I would like to have 2 6 inch ports. I guess I would essentially make an elbow though and extend it from the end point then go up to the top level of the box. I could then plexiglass a complete cover from the back of the box (aero side) all the way to the end of the usable area I have (the square at the bottom) and have all electrical and equipment in that.... hmmmmm

Any other ideas for placement?

Edited August 27, 2009 by holley2346

[Zach Gates 0]

Well if you really want 2 6" ports, keep in mind their necessary length.

Then what I'd probably do is have them mostly external, and then make sort of a "second box" just for them, then carpet the whole thing. From the outside it'll look like you have one huge box with two ports, but the top 8" or so are sealed off from the rest of the box, all that's in that space is port. I don't have any CAD programs so I can't make a good sketch, unfortunately, but this'll work:

Actually a good idea in general. I may end up doing something very similar...

[holley2346 6]

Well if you really want 2 6" ports, keep in mind their necessary length.

Then what I'd probably do is have them mostly external, and then make sort of a "second box" just for them, then carpet the whole thing. From the outside it'll look like you have one huge box with two ports, but the top 8" or so are sealed off from the rest of the box, all that's in that space is port. I don't have any CAD programs so I can't make a good sketch, unfortunately, but this'll work:

Actually a good idea in general. I may end up doing something very similar...

That looks good... I've decided to go with 2 4" ports because its so much easier.

This is what I have as of now.

That is with 2 PowerBass amps (top) and SA3000D on bottom. All dimensions are accurate.

Suggestions are welcome. I am having trouble finding room for the bats.

Edited August 27, 2009 by holley2346

[Zach Gates 0]

This is outside my realm, but I'm thinking 2 4's might be a hair small for a box that big. Just make them 6" wide, extend a few more inches into the box, make the whole thing an inch or two wider to compensate for more port displacement.

That's a sexy design dude.

[holley2346 6]

This is outside my realm, but I'm thinking 2 4's might be a hair small for a box that big. Just make them 6" wide, extend a few more inches into the box, make the whole thing an inch or two wider to compensate for more port displacement.

That's a sexy design dude.

According to the calculator it should be perfect. The design is alright... it's just hard fitting all this stuff where it can be seen. I still don't have a place for my EQ/horns/additional drivers.

[Zach Gates 0]

I just mean small in the "there might be some port noise" sense, not that the tuning would be off. But then I honestly have no idea if there would be at 4" ports, that should be plenty but some on these old internets have their opinions about having huge ports.

Anyway, can't wait to see the finished project!

[hispls 23]

Looks like a pretty efficient use of space.

If you have a sedan (can't see from the pic) Do be sure you don't block off all the airflow between trunk and cabin. You'll lose a ton of output. Also if you can spare the wood and time building a temp box that's small enough to move around and test different angles will help a LOT. You may find a HUGE difference in freq response and output by just pointing the woofer/ports in different directions. Also, don't rule out using passive radiator(s) in place of ports if you want to save space.

[Aaron Clinton 2,372]

Looks like a good layout.

[holley2346 6]

Looks like a good layout.

Thanks

Here is what I've got now, I'm revising it but the final should be pretty close.

Please ignore the hole for the sub, the outside dimensions are accurate. And the back sloping panel is accurate.

Equipment is:

2 Powerbass ASA800.2's

2 Eminence APT80 Horns (between the two amps on the top)

4 SEAS Prestige 4.5" midwoofers (I still am considering a couple of other drivers)

2 SB Acoustics 4" midranges

2 4" flared ports (from partsexpress)

Also; already on hand:

Sundown Audio 3000D

Fi Audio BTL 18

2 Optima Yellow tops

KnuKonceptz 1/0

This still isn't the final, but is pretty close.

Opinions are welcome. It will be shorter than my existing box, should be close to ~16 inches high.

Edited August 31, 2009 by holley2346

[holley2346 6]

Would it be okay to mount the yellow tops on their side? I can't really find any other way to fit them under the amp rack.