[bluesidan]

In trying to figure out the line area I am confused. If I use the sd I get 74.5in2 but if I measure from the center of the cone to the middle of the surround I get 90in2. Which one do I use? It seams as though the manufacturers numbers would be more acurate but why the big differance?

Someone help, please!

[alove4242]

Small measurement errors in your radius can make a big difference in area calculations. Try measuring from middle of surround to middle of surround (being careful to line up what you think is the center point of the cone). Anytime you can double your raw measurement, you cut error percentage in half. The manufacturer may also use a different measuring method than the mid-surround. I don't know if there is a truly universally accepted method, since surrounds behave differently between manufacturing methods and materials.

Even if you are off by ~10%, I doubt it will be a major issue. If you build the line with a cross-section area of the larger number, it should still work fine, and the area does not affect other variables like line tuning length etc.

[bluesidan]

Turns out that I am a moron and forgot that I started the measurement at the 1 instead of 0

When I measured the first time I got 10.9" which is what the scale said at the peak of the surround. I got the same thing when I measured this time but the other side of the scale was at 1 not 0. (Starting at 1 makes it easier to see if the scale is at the peak of something)

So this time I calculate 76in2 compared to the T/S parameters at 74.5in2. I think I will trust the T/S parameters and build it from there.

I have a design, just need to get my friends table saw over here.

I have a FI Q12 that will have a NINe.5 feeding it. I have read that most T-lines only require 200-300 watts or so. How will I know when to stop giving it power? This is my first T-line box and I am using this setup as an experiment before building one for my HT setup.

Any help is welcome, thank you.

[alove4242]

Originally Posted by bluesidan

I have a FI Q12 that will have a NINe.5 feeding it. I have read that most T-lines only require 200-300 watts or so. How will I know when to stop giving it power? This is my first T-line box and I am using this setup as an experiment before building one for my HT setup.

Any help is welcome, thank you.

Similar to ported setups, if you hear weird noises, smell strange smells, or see too much cone movement, bring down the power. Though it might seem like a long box with a big hole, there is still a fair amount of acoustic suspension with tlines and you aren't too likely to blow anything up before you get some warning signs.