Port Length & End Correction ????

[FusionX_876]

Hey Guys

I've Been trying to design a custom enclosure for a single 12" subwoofer that I reconed the other day. I chose to go with 1.75 cu.ft net because I don't want it to take up too much space. I'm aiming for sq so it's tuned to 32hz with a port length of 37.53125" after adding half the width of the port to the port length for end correction. I understand how to calculate the volume and get the port size etc, but I just don't understand how to implement the port length into the box and why is end correction needed and when should I use it. Below is the tuning sheet for a box I designed and some Sketchup mock-ups of how I implemented the port length. Is this the right way to implement the port length ? 

Tuning Sheet - https://gyazo.com/dbb10f2776378393c2f75c803f8f935b

(Port Length, Everything Adds Up To 37.53125") 

1) https://gyazo.com/64844f201bdff2e1cfa9d782e5b9e9e5 (14.53125")

2) https://gyazo.com/25bcd62b6741ac96a11e3a4ff131818b (2.8125")

3) https://gyazo.com/6cd267fe61653fd1dde4e023a852e9d2 (12.75")

4) https://gyazo.com/f53a10a44bfc709df38b16b183318630 (2.8125")

5) https://gyazo.com/ea782f06c709b51be73d75b2d4686bff (4.625")

 

[MotorCityFats13]

none of the links you shared are working for me...

when your port shares a wall of the box you use end correction to dial in a more accurate tune.... more correction is needed if your port shares more then 1 wall.... but to my understanding the port gets shorter after correction so if you don't use end correction the tune will be lower and its not the end of the world unless you are into competitions

looking at the link titles it looks like you plan on making a slot port with multiple bends and reading multiple threads from some of the most famous box designers on the smd forums I think they said to avoid more than 2 or 3 bends and not to exceed 32" port

I cant hear a difference between a 31hz and a 32hz tune

[ckeeler11]

Torres calculates end correction so no need to add it in. That's why they ask the number of common port walls.

[Triticum Agricolam]

MotorCityFats13 pretty much covered it.  Torres has built in end correction, if your tuning is off a Hz or two in either direction, you won't notice.  I try to keep ports under 44", so you should be fine.

As far as you port layout goes, I try to avoid 180 degree turns as much as possible.  You should be able to run your port to the back, make a 90 degree turn and then run it along the back wall to avoid all those turns. 

 

[DLHgn]

2 hours ago, Triticum Agricolam said:

MotorCityFats13 pretty much covered it.  Torres has built in end correction, if your tuning is off a Hz or two in either direction, you won't notice.  I try to keep ports under 44", so you should be fine.

As far as you port layout goes, I try to avoid 180 degree turns as much as possible.  You should be able to run your port to the back, make a 90 degree turn and then run it along the back wall to avoid all those turns. 

 

What are the disadvantages of adding a 180 degree bend in the port? 

[Triticum Agricolam]

 

4 hours ago, DLHgn said:

What are the disadvantages of adding a 180 degree bend in the port? 

180 degree bends are more disruptive to the airflow than 90 degree bends are.