first transmission line with usd 1260 subs

[thecat666 0]

i would like some idea's please i have about 3.352 cft internal external 40.5"width 10.5"height 18 depth,i wish to use 2 or 3 old usd 1260 subs. speaker paremeter RE 5.24 QTS 0.39 QMS 15.60 FS 12.29

QES 0.40 XMAS 3.708 LE 1.01 Z 8 OMH PE 200 i would like to try and build a transmissione line box. i found this info for building the above box.please can any one help me all help will be gratefuly recieved. below is an example of how to make a transmission line

43.46 / 4 = 10.86

10.86 is the throat length of the enclosure. Designing a transmission line enclosure

________________________________________

sample specs.

--

radiating area of subwoofer - 60 in^2

free-air resonant frequency of subwoofer - 26hz

formula.

--

speed of sound (1130) / resonant frequency / 4 = throat length

throat width.

--

radiating area of subwoofer / internal hight of enclosure = throat width

==============================

using the sample specs i listed above we come up with

1130 / 26 = 43.46

===================================

now lets say the enclosure will be 14 inches tall. using one layer of 3/4 inch material, will yield a 12.5 inch internal height.

now we figure the throat width.

60 inch radiating area / 12.5 internal height = 4.8 inch wide throat.

==============================

lets figure 3 bends for example.

10.86 feet / 3 bends = 3.62 feet wide

3.62 x 12 = 43.4 inches wide.

==============================

is this correct?. thanks for any help given

Edited November 18, 2007 by thecat666

[JimJ 11]

Unless I'm missing something, you've just calculated a box that won't fit in your available space...that's not a lot of room for anything, I think you'd be better served with a more traditional bass reflex or sealed.

[thecat666 0]

Unless I'm missing something, you've just calculated a box that won't fit in your available space...that's not a lot of room for anything, I think you'd be better served with a more traditional bass reflex or sealed.

the above figures are what came with the example,the others at the top are the actual speaker parameters for 1, usd 1260 sub .i have not posted my own workings out for that type of enclosure yet

Edited November 18, 2007 by thecat666

[thecat666 0]

im trying to find out if this is the correct method for transmission line box,

below is an example can some one please tell me if this is the correct way to work it out.

43.46 / 4 = 10.86

10.86 is the throat length of the enclosure. Designing a transmission line enclosure

________________________________________

sample specs.

--

radiating area of subwoofer - 60 in^2

free-air resonant frequency of subwoofer - 26hz

formula.

--

speed of sound (1130) / resonant frequency / 4 = throat length

throat width.

--

radiating area of subwoofer / internal hight of enclosure = throat width

==============================

using the sample specs i listed above we come up with

1130 / 26 = 43.46

===================================

now lets say the enclosure will be 14 inches tall. using one layer of 3/4 inch material, will yield a 12.5 inch internal height.

now we figure the throat width.

60 inch radiating area / 12.5 internal height = 4.8 inch wide throat.

==============================

lets figure 3 bends for example.

10.86 feet / 3 bends = 3.62 feet wide

3.62 x 12 = 43.4 inches wide.

[JimJ 11]

It's the correct way to get a starting point. TL's require that you build, test, rebuild, test, as needed until you get the desired results. They don't just happen unless you get very lucky or are copying a design from someone that already did the time consuming part.

I still think 3 cF is too small.

[thecat666 0]

this is my working out for 2 usd audio 1260's, 1130 / 41 = 27.56 / 4 = 6.89 ft (1/4 wave) throat length.

5.75 (1/2 of enclosure height) x 5.75 x 3.14 (pi) = 103.81 sq in.

103.81 x 2 (number of speakers) = 207.62 sq in

6.89/3 (number of folds) = 2.29 ft.

2.29 x 12 ( converting into inches ) =27.55 inches long.

port length = 27.55 inches long,

port area =23.06 sq in.

is this correct its just something i want to try out