A little help with a t-line enclosure please

[garychoffmann 10+ year member]

I am going to build a t-line for 2 Tang band 8's. I'm hoping someone with some experience with t-lines will jump in here. I'm stuck up at the hospital with my sick infant so I have limited internet capability and alot of down time so I'm designing a system for one of my cars using the info I have. This way when I get to work on it I'll have everything mapped out and pre-planned.

The speakers are tang band w8-740p, here are the specs:

FS 28hz

Vas .81

QMS 10.53

Qes .30

Qts .30

Cone area is roughly a 7.5 diameter so 45 square inches to make it easy.

So my mouth area is going to be 45 inches square or 9"x5" and the length I'm looking at is right at 7.5 feet. Anyone have any different suggestions? I'm looking for tuning in the 28-35 hz

There seems to be ALOT of contradicting info on t-lines so before I waste good wood, I'd like a second opinion. Thanks for your help.

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[RAM_Designs 5,000+ posts]

7.5ft isn't going to give you a tune that low. Do 8ft in length for a 35hz tuning, 9.5ft for 30hz.

 

[garychoffmann 10+ year member]

Thanks for the Reply Ram, now I've heard 2 different stories about the port area, If I'm using 2 subs do I need to double the port area to 90 square inches? Thanks for your help, I appreciate it

 

[RAM_Designs 5,000+ posts]

Thanks for the Reply Ram, now I've heard 2 different stories about the port area, If I'm using 2 subs do I need to double the port area to 90 square inches? Thanks for your help, I appreciate it

Generally you want the port area to equal the cone area of the the speakers you're using. If 45in^2 is for one of your subs, then yes, 90in^2 is what you're going to want to use as a starting point.

 

[RAM_Designs 5,000+ posts]

Better yet, do you have a link to the t/s for the sub? You can take the sd, which is normally given in cm^2, and divide it by 6.45 to get the equivalent sd in in^2.

 

[garychoffmann 10+ year member]

Ram, I'll see if I can find one but I think you goofed your math a littel bit. 7.5 /2 = 3.75, so area equals 3.14 X (3.75x3.75) equals 44 and some change. Maybe I'm wrong, but I'll try and find manufacturer specs

 

[RAM_Designs 5,000+ posts]

Indeed I did, accidentally hit the 6 on my calc instead of 7. Fat fingers FTL //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif