looks fine. center piece will be cut to 2.6" though, just to let you know.

I didn't think that was right, but now that you said so, I'm OK. It just seemed too short to me.

I didn't think that was right, but now that you said so, I'm OK. It just seemed too short to me.

Big box + small port + medium tuning = short port.

When I use that calculator for 2 ports, is the port length combined between the 2 ports or per?

the port length shown for more than 1 port is the length requirement for EACH port, not combined length!

Did you freak out, hehe? It does appear pretty long but that is what happens when using multi ports

I do have a major question?

I seen that someone made reference to PSP, i have read on their site, klausaudio's site and subwoofer-builder.com(think that's the name) and none of these sites allow calculations for the amount of power going to be used!?!?

These calculators help determine length but you must give the port area to do it.

The problem i'm seeing is when I build an enclosure, I may only have just enough space for an optimal install. To gain NET volume, I have the option of going with flared port(s). Using box modeling software, i am able to see calculated port velocity and calculated port length by giving the software a port area just like with these other calculators.....but there is a difference.

Air speed in the port does not flow slower just by increasing port area, or not just by using flared port(s), but also by decreasing output power from subwoofer(s).

So... how can these calculators properly give me an appropriate port if i have to guess on the port area without seeing a port velocity graph?

I am trying to do some research on if and how much a flared port can reduce port area requirement before you fall below a specified speed of air at a given frequency.

For instance, one source says not to exceed 145ft\sec for daily driver or not to exceed 37ft/sec for SPL applications.

So, let's say i don't wanna exceed 130ft/sec or i will have audible turbulence(theoretically).

This software does NOT take into consideration that flared ports may be able to decrease the required port area based on the outer size of the flange(i guess because it would be too complicated due to angles and such).

So, this software tells me for a 2.7 cu ft box NET at 35hz with 3,000w of power before resistance rise, I would need a port area of 41.25sqin but with 4,000w i would need 47.25sqin, 1,000w is 23.75sqin.

You see how power is very relevant in these calculations for designs that need as much space in small spaces as possible. So...

In this design i am doing, i need 41.25sqin of port area for this box. If flared ports decrease the required port area required,(meaning i can make a flared port that takes up less space in the box and still get the same results as a slotted port) how much do they decrease this requirement?

Complicated question? I am very curious to know how small can the diameter of a flared port can be made to keep your DIY applications to fall within your personal limits of port velocity to retain as much NET volume as possible.

I am also curious to know how I go about calculating the volume a flared port takes up? And no i do not have any measuring device methods such as filling box with water.

When I use that calculator for 2 ports, is the port length combined between the 2 ports or per?

http://mobile.jlaudio.com/support_pages.php?page_id=165

I do have a major question?

I seen that someone made reference to PSP, i have read on their site, klausaudio's site and subwoofer-builder.com(think that's the name) and none of these sites allow calculations for the amount of power going to be used!?!?

These calculators help determine length but you must give the port area to do it.

The problem i'm seeing is when I build an enclosure, I may only have just enough space for an optimal install. To gain NET volume, I have the option of going with flared port(s). Using box modeling software, i am able to see calculated port velocity and calculated port length by giving the software a port area just like with these other calculators.....but there is a difference.

Air speed in the port does not flow slower just by increasing port area, or not just by using flared port(s), but also by decreasing output power from subwoofer(s).

So... how can these calculators properly give me an appropriate port if i have to guess on the port area without seeing a port velocity graph?

Figure how much power you're going to run. Figure what tuning you want and the boxvolume that you need. From there you actually base your port area on the velocity and length based on that port area. WinISD is pretty darn good for this, especially for the price (free). You can then account for the difference made by the flare manually. I'm not sure at what point the flare fails to make a difference in port noise, but at some point, the velocity in the throat of the port will be high enough that the air in the port begins to compress and the flare is useless.

I am trying to do some research on if and how much a flared port can reduce port area requirement before you fall below a specified speed of air at a given frequency.

For instance, one source says not to exceed 145ft\sec for daily driver or not to exceed 37ft/sec for SPL applications.

So, let's say i don't wanna exceed 130ft/sec or i will have audible turbulence(theoretically).

This software does NOT take into consideration that flared ports may be able to decrease the required port area based on the outer size of the flange(i guess because it would be too complicated due to angles and such).

So, this software tells me for a 2.7 cu ft box NET at 35hz with 3,000w of power before resistance rise, I would need a port area of 41.25sqin but with 4,000w i would need 47.25sqin, 1,000w is 23.75sqin.

You see how power is very relevant in these calculations for designs that need as much space in small spaces as possible. So...

In this design i am doing, i need 41.25sqin of port area for this box. If flared ports decrease the required port area required,(meaning i can make a flared port that takes up less space in the box and still get the same results as a slotted port) how much do they decrease this requirement?

Complicated question? I am very curious to know how small can the diameter of a flared port can be made to keep your DIY applications to fall within your personal limits of port velocity to retain as much NET volume as possible.

I am also curious to know how I go about calculating the volume a flared port takes up? And no i do not have any measuring device methods such as filling box with water.

The flare reduces the velocity at the exit point proportionally to the ratio of the areas of the outer flare diameter and the throat of the port.

I could read until my head hurts and I DO!!! LIke Duran said a couple of days ago how he still reads the tech section from time to time. So I have reprimanded myself here.

Long behold I learn the relationship between port velocity and amplifier power from Shizzzon.(ya, you got my vote)

Since We have been dissussing kerfed and areo ports alot lately this helped me to understand a LITTLE more!!! As helped me understand WinISD a Little more.

Now back to School........