Need T-Line Box Design

[tremor1127 10+ year member]

Hello. Needing a t-line box designed. I will be responsible for bracing, 45s, etc, I just need a good raw box design with cut sheet.

Max space is 40wideX13tallX24deep. I want to keep the width 40" and the height 13", leaving the depth to work with.

Subwoofers being used are two v.3 10" Image Dynamics IDMAX. ID recommends around 1.5cuft tuned to 25hz (feel free to tune to around 30hz). Power will be around 1500rms to the pair. Here is some specs on the subwoofers.

View attachment 26551316

Here is a simple example of what I am shooting for. Port can be on other side if thats how it works out on paper. All I am concerned with is that its subs back and port side.

View attachment 26551317

Thanks guys...

Click to read more...

 

[tremor1127 10+ year member]

Or someone send me in the right direction.

 

[keep_hope_alive Premium Member]

what you have drawn will behave like a ported box. you have a large chamber with a port.

T-line needs to have the same cross-sectional area as the cone surface area (total). if you do a chamber-coupled T-line the chamber should be as small as possible.

Fs is 20.4Hz. if you want to shoot for a line length that is 1/4 wavelength of that, it's 14 feet long. not likely given your dimensional limitations. at 30Hz the line length is 9.4 feet.

length for 1/4 wavelength is just (1125/f)/4

1125 is the speed of sound in feet per second

f is the frequency of interest

the final division by 4 is just for 1/4.

your best resource for T-Line design is the Loudspeaker Design Cookbook, 7th edition.

 

[tremor1127 10+ year member]

I understand but the drawing is just an example. I have 40wideX13tallX24 deep to work with. Im open to any suggestions but want to keep subs back with port to either side. Im also not against tuning somewhere between 25 and 30hz.

 

[keep_hope_alive Premium Member]

cone area (sd) is 60 sq. in. per sub. that's 120 sq. in. for the port. your height of 13" means the max internal port height is 11.5" (3/4" wood top and bottom, one layer). that means the port width is 10" throughout. The subs need 7" + 3" for rear cooling. so basically, your only design is what you drew, minus the two lines in the middle. you have about 60" of line length which means your tuning is 56Hz.

you don't have near enough size for your plan to use two 10's. TL's are HUGE when cone area increases.

this is a TL for one 8" tuned to 42Hz i did recently.

partial construction. had some more 45's and a double thick front baffle at the end.

 

[keep_hope_alive Premium Member]

now, if we drop to a single 10" sub, things become more reasonable. TL line width is now just 5.2". Line length can be 118" which is 28Hz 1/4wave tuning (using your max dimensions).

 

[tremor1127 10+ year member]

Makes alot of sense now, seeing one built for one 8" lol. Can you do get me a sketchup like that for one then? 40" wide X 13" tall with max depth of 24". Just have the port exit the side right there instead of the front.

 

[tremor1127 10+ year member]

I will be doing the 45s and countersunk baffle exactly how you did on the box you built. Very nice btw!

 

[CSCStang]

cone area (sd) is 60 sq. in. per sub. that's 120 sq. in. for the port. your height of 13" means the max internal port height is 11.5" (3/4" wood top and bottom, one layer). that means the port width is 10" throughout. The subs need 7" + 3" for rear cooling. so basically, your only design is what you drew, minus the two lines in the middle. you have about 60" of line length which means your tuning is 56Hz.
you don't have near enough size for your plan to use two 10's. TL's are HUGE when cone area increases.

this is a TL for one 8" tuned to 42Hz i did recently.

partial construction. had some more 45's and a double thick front baffle at the end.

Is that a p2?

 

[keep_hope_alive Premium Member]

Is that a p2?

yea. wasn't my idea but worth an evening of work. i would have preferred a sub with a much lower fs. owner is happy, in the trunk of a 2013 Charger.

 

[keep_hope_alive Premium Member]

Makes alot of sense now, seeing one built for one 8" lol. Can you do get me a sketchup like that for one then? 40" wide X 13" tall with max depth of 24". Just have the port exit the side right there instead of the front.

yea, gimme the weekend to work it in. i've already sketched the design on paper.

 

[CSCStang]

yea. wasn't my idea but worth an evening of work. i would have preferred a sub with a much lower fs. owner is happy, in the trunk of a 2013 Charger.

I noticed it has an fs of 39.6. So you just tuned the box up to 42?

 

[LosIsATool 5,000+ posts]

now, if we drop to a single 10" sub, things become more reasonable. TL line width is now just 5.2". Line length can be 118" which is 28Hz 1/4wave tuning (using your max dimensions).

I'm going to have to get with you about a T line for a Epic 8

 

[keep_hope_alive Premium Member]

I noticed it has an fs of 39.6. So you just tuned the box up to 42?

around there, i was shooting for around 40 and mean path length was about that - but the chamber loaded style has some effects on tuning, i suspect it bumps it up a bit.

 

[tremor1127 10+ year member]

Ok bud. Cant wait. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif