Sundown E10 T-Line Help

[Zach Bruning]

What's up SMD forums? This is my first post and I was wondering if someone could check my T-Line design (also a first) and make sure the numbers

add up. Thanks in advance guys.

[Krakin]

Your port looks a little big at 63 square inches. I would see about trying to make those turnes rounder just to make it easier for the air to flow. I would either wait to redesign till after you have your sub so that you can get the actual cone area measured from 1/2 of the surround to the center. Or try to find someone on here that has one to do it for you.

I haven't checked your port length yet but just eyeballing it look okay.

Edit: It's pretty hard for me to tell the port length with the dimensions given. If you could, could you check it yourself by drawing a line down the middle of the port from the beginning to the end and post the results.

[Chris Hammer]

Havign the port area larger or smaller then the actual cone area changes the output. I know there is a more in depth explanation on here somewhere...but if my memory serves me right..IF...then the larger area will peak the output more while a lower port area will have a flatter response.

How long is the port measured from center for the entire length? That would tell us your tuning.

Also 45's or making your bends rounder can increase, or decrease you output...so don't think everything needs 45's. They are over rated IMO.

Neither of my 1/4 tline builds used 45's. I tried them on my first one and actually removed them....it was Louder(by ear) without them. I won't use them anymore.

Sundown list the cone area if I'm not mistaken..so go of that...Its more complicated to calculate exact surface area by measuring because you are not measuring surface area of a circle..you are measuring somehting cone shaped.

[Zach Bruning]

Sorry it took me a day or two to post back my weekend got started early. But i did some measuring and I think i got things figured out. Couldn't find the cone area of the E10 anywhere so I measured my sub with the tape running flat with the cone and from mid-surround to mid-surround i got 9 inches. Which gives me a cone area of 63.5 in squared. I ran a line down the center of my port in sketchup and i got a full length of 102.5 in. I think you are supposed to subtract 7-8 inches for the sub so that would give me like 95 in of port length. I'm tuning to the Fs of the sub which is 36 hz.

[matt scarlett]

1) A 1/4 wave transmission line doesn't have a "Port" it has a line width that is guided by a wave guide. Due to the size of the subwoofer, unless you go for a tapered t-line, the 'Line Terminus' has to be what it is. I'm currently running an SA-12 win a tapered t-line with a line terminus of around 4 " (if my memory serves me right without running to the car and checking).

2) 45's seems to be debatable at best. Some say to reduced corner turbulence, some say (in the case of t-lines) to keep the line constant.

Zach Bruning, on 23 Mar 2013 - 20:12, said:

in sketchup and i got a full length of 102.5 in. I think you are supposed to subtract 7-8 inches for the sub so that would give me like 95 in of port length. I'm tuning to the Fs of the sub which is 36 hz.

3) The reduction is to do with 'Boundary End-correction' and if the design is not optimised then around 5% should be good.

On a personal note, I tune to what I want, not to the maunfactrers Fs figure. For good good measure, and because most of the true T/S parameters I’ve seen taken from enthusiasts, seem to be different to the manufacturers figures, and sometimes not by a small margin either I aim for around 5 Hz more than the prescribed Fs figure.

Again on a personal and final note, I try and use a few-a-folds as possible. I tried similar output goals using a JBL GTO 804 sub. The more folds there were ... audibly, there was always something lacking.

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