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View Full Version : My go at a transmission line box



mobeious
04-21-2007, 10:25 PM
Ok i was bord so i tried my hand at a T-line box for a rockford P3 12" i had laying around .... total box volume was 4.5 cubes with a line length of 115"

Intitial listing = the box has a warm sound to it real responsive, it was as loud as the ported box it replaced... was a little quicker on responce.. my opinion is that i would take the ported box over the T-line and just leave the T-line for home audio were is was born.... BTW if u need a box built PM me


http://i7.photobucket.com/albums/y290/mobeious/Picture002-13.jpg

http://i7.photobucket.com/albums/y290/mobeious/Picture001-12.jpg

BASS_WARRIOR
04-21-2007, 10:28 PM
so if it was just as loud but with quicker response why would you take the ported box over it?

oxsign
04-21-2007, 10:29 PM
Very nice looking. What are the demention to that box there?

mobeious
04-21-2007, 10:39 PM
the ported box was a lil louder but not much... and the ported box is half the size of this thing... i just built it for fun,, not to keep it

dimentions are 30wide 13tall and 27.75 deep

oxsign
04-21-2007, 10:45 PM
dimentions are 30wide 13tall and 27.75 deepNice, let me know what you would want for that box there. I can meet you somewhere. I may be interested if you deside to sell it. I have a nice 12" that i'd like to try out in that thing. :naughty:

ballstothewall
04-22-2007, 01:45 AM
Don't you tune a T-line to what you want the desired Fs to be??

Immacomputer
04-22-2007, 02:17 AM
The line length should be 1/4 the wave length of the Fs of the driver to get the desired effects.

htownplaya456
04-22-2007, 05:43 AM
Well now that I know how the length is determined what about width and height?

Showrides
04-22-2007, 06:05 AM
That looks very nice. I have never built a TL box before, but have heard a few. I do have a basic box building question though. How do you keep it so clean? My boxes always sound good, but I always have glue dripping out of every joint. Maybe I just go a little crazy with the wood glue :)

ballstothewall
04-22-2007, 10:13 AM
The line length should be 1/4 the wave length of the Fs of the driver to get the desired effects.

Forgot the 1/4 wave part... I was wondering why the hell it was tuned to ~115Hz, lol

Immacomputer
04-22-2007, 01:03 PM
Well now that I know how the length is determined what about width and height?

That depends on the speaker you're using. It is usually recommended to do about .75 to 1.5 times the Sd of the driver. Much below that and you lose low end extension and much higher you lose upper frequency extension (when using subs). Also, you can taper the line which can increase sound quality by reducing upper order harmonics escaping through the line opening.


That looks very nice. I have never built a TL box before, but have heard a few. I do have a basic box building question though. How do you keep it so clean? My boxes always sound good, but I always have glue dripping out of every joint. Maybe I just go a little crazy with the wood glue :)

Use a damp rag and wipe it up right as it spills out. This usually leaves a yellow streak for me no matter how much I try to wipe it up so I started using masking tape on the joints and it worked out very nicely.

lilmaniac2
04-22-2007, 01:05 PM
i just sand the yellow residue off

mobeious
04-22-2007, 07:45 PM
ok it was designed around a Rockford P3 12" woofer wich has a Fs of 29hz so u do 1130/29=38.96feet then u take 38.96/4 for quarter wave and get 9.74 feet then u times that by 12 to give u inches and u get 116.88 inches thats ur line length... to get the depth of the line u need 2 things sq in of woofer and box height u take sq in of woofers wich in my case was 70sq and divide it by internal box height which was 11.5 wich gives u 6.08inchs depth so ur line is 6" deep by 11.5 tall

vetkilr
04-22-2007, 09:01 PM
So how big does one have to be to fit a Massive Stage 2 DMX 15"?

mobeious
04-22-2007, 10:02 PM
whats the Fs on the sub and coneaera

baseballer1100
04-22-2007, 10:53 PM
sweet dude.

mobeious
04-22-2007, 11:14 PM
i want to try a rear or front loaded horn... but i dont know how to design one of those

newusername
04-22-2007, 11:19 PM
www.quarter-wave.com

Generic and simplistic formulas don't make for effective TL's.

ballstothewall
04-23-2007, 12:25 AM
www.quarter-wave.com

Generic and simplistic formulas don't make for effective TL's.

I found a copy of mathcad awhile ago just to play with those worksheets. :up2somet:

vetkilr
04-23-2007, 08:47 AM
whats the Fs on the sub and coneaera

fs 43.55
SD is 128.65 in.

PV Audio
04-23-2007, 04:02 PM
i want to try a rear or front loaded horn... but i dont know how to design one of those
Note my sig :crap:

mobeious
04-23-2007, 10:17 PM
ur box would be around 5.75cubes roughly thats with just doin it in my head

dleccord
04-23-2007, 10:59 PM
clean lookin box.