has anybody heard of transmission box before?

the reason i ask is because i have one 15 ma audio woofer laying around and i felt like making a custom box for it. I heard good stories about this boxes and ive been told that this boxes will be loud as two woofers combined. Around here these boxes cost like around 200-300 depending the size ofcourse. i was wondering what size of box is recommended and how many chambers.

 

Do you mean "Transmission Line" sub box?
Anytime you add an "order" to a box you will gain output, EG: the same speaker driven with the same power in a vented box will be about 3dB louder, [twice as loud] as the same speaker in a sealed box, SPL, [gain] can also be realized when using "Band Pass" box's, there are many configurations for band pass box's, from a 2 chambered box, [ sub(s) mounted into sealed chamber and firing into the 2nd chamber that has a tuned vent] to multiple chambers and subs, [subs mounted into individual vented chambers all firing into a single vented chamber].

The more chambers and vents you add to a box, [orders] the more difficult it becomes to design and build the box, a sealed box is relatively easy to build, [keep the net internal volume within +/- 10% of optimum, put at least one angled surface on it and stay as far from a cube as you can, no 12"x12"x12" 1 cu.ft. box's] your done, as soon as you move up to vented or ported or tuned port, [they are all the same, a box with a hole in it] it is the volume of that hole that is critical, [square, round or rectangular] the internal and external volume of the "port" has to be taken into account not only for it's internal volume for tuning but also in the overall volume of the box, generally the gross internal volume of a tuned port box is more then a sealed box by the amount of the external volume of the part of the port that is inside the box, and the net internal volume of a vented box needs to be within +/- 1% and vent/port volume has to be pretty much on the button.

Needless to say band pass box's are very hard to get exactly right, and yea you can go and buy a pre-built band pass box and stick a sub into it, use a quick calculation and get a recommended port volume, [or port length] for it, put it all together, but it is hardly the right setup, and generally sound like crap, or at the very least you do not get the full potential of the sub.

The first thing you are going to need is the Thiele-Small parameters of the sub you have, what is the brand and model if the sub? 94

 

a bandpass would not be a bad idea because it would work. I could easy get any of these boxes(sealed,vented,b.p.) for a good price. Now a transmission line box are costly. I heard so many good stories about these and i really want to built one. Do u really think is hard to make or calculate one of thes boxes?

Is it really to hard to calculate the chamber size? what length for the vented slot?

 

it is very challenging to accurately model a transmission line enclosure's response curve ahead of time. you can start with a general idea and modify from there to try and net the best response.

now when it comes to bandpass boxes, i love a nice 4th order bp. get nearly the group delay of a sealed enclosure and nearly the efficiency/output of a vented enclosure. when done with a passive radiator, you can get incredibly favourable results in an enclosure not much bigger than a sealed one.

i also have just started doing triple reflex 8th order bp's. they are a lot more painstaking to model, design, and build. but i do this for fun so i can't say i'm too bothered by it

 

is there a website u can direct me so i can the idea of these order boxes.

 

http://www.t-linespeakers.org

have a read through this:
http://www.partsexpress.com/pe...0-040

discusses design of some of the more exclusive enclosure designs, like the front/rear folded horns, tl's, bp's, etc. definitely worth a read.