Box Concepts

[Forevrbumpn]

http://www.stevemeadedesigns.com/board/ind...?showtopic=1828

basic but very doable formula, design info

If you want the real shit, and know how to do some serious math, Look up Martin King , he is a very reputable person in this area, and his formulas for tapered designs are all over the internet

[Forevrbumpn]

Forevrbumpn what do suspect will happen the freq response with the 1/8th wave vs 1/4 wave?

1/8th wave is to unpredictable, and the catch is, you fill the line up with polyfill, and hope for the best

Unless you calculate the 1/8wave at double the cars cabin resonance, which should be the SPL peak tuning anyways

but it should play somewhat flat down to double the 1/8th wave- IN CAR Response

[BigPimpin91]

I love quarter waves man, Iam diehard on them. You can do 1/8th wave, because when you do a quarter wave at say 40hz, depending on the subwoofer, it will go down to 20hz anyways in car response....

I do on a regular basis, 40hz tline bandpasses, but in car response is amazing with the right woofer...

My old home theater tline bandpass was 40hz tuned with a 20hz 3db gain on 250 watts, but boy did it shake the house from about 50-20hz easily...

its really trial and error

However, Mine does not.

Or I can't hear it but I can hear the back glass mechanism vibrating to shit.

Also, be responsible and careful when dealing with T-Lines.

Use a Sub Sonic Filter.

I tried feeding 20hz to a 12" on 950w with a Line tuning of 38 and it was not happy.

Made the weirdest noise I ever heard.

However,

For kicks and giggles I put my sub back into a 4th Order badnpass because that box SEEMED to peak in the 40-45hz range where I like music and the out put difference between T-Line and Bandpass is VERY Noticeable.

All I have to say after 2 days of comparing the two. T-Line > Bandpass.

[Forevrbumpn]

That was 20hz boost on a 40hz tuned tline bandpass- horn/line, I build them pretty often, they pound like crazy below tuning

in a standard Tline, you gotta rely on transfer function of the car to drop below tuning, which isnt hard for a tline in a car

That 10" I had was in a 1.75cf sealed chamber firing in a 40hz line that started the line off at half the cone area and ended at the mouth 1.5 the cone area

using that method has gotten many 10s playing same freq response as many 18s

I got proof in my garage and in my gfs intrepid ;-)

[Bigg Boy]

That was 20hz boost on a 40hz tuned tline bandpass- horn/line, I build them pretty often, they pound like crazy below tuning

in a standard Tline, you gotta rely on transfer function of the car to drop below tuning, which isnt hard for a tline in a car

That 10" I had was in a 1.75cf sealed chamber firing in a 40hz line that started the line off at half the cone area and ended at the mouth 1.5 the cone area

using that method has gotten many 10s playing same freq response as many 18s

I got proof in my garage and in my gfs intrepid ;-)

and that was 1/4 wave? whats the sealed part for, added suspension?

[Forevrbumpn]

its a bandpass, 4th order transmission line box

its a sealed sub, firing in to a transmission line or horn

[BigPimpin91]

its a bandpass, 4th order transmission line box

its a sealed sub, firing in to a transmission line or horn

Which I was contemplating doing.

[Forevrbumpn]

This box designs works this way, think of this....

Say you have a 30hz tone, you got peaks on a meter every 1/8th, 1/4, 1/2 and full wave, if in a tunnel....

So imagine being in a short tunnel(compact car say 7ft long), but you want a lower frequency response in that tunnel, what you do is extend the tunnel length

if you get a sealed box, fire it in a tunnel equally as long but just wind it up in to a single enclosure, and thats will increase low end response as if you were in a tunnel twice as long (14ft internally-say suburban or extended van)

its imagination - gotta imagine how the sound waves work, length of the sound waves, converting a quarter wave design to a 1/8th wave or 1/2 wave

If you are going for SPL, and say you have a explorer, the peak spl tuning is like 54hz, but for SQ it should be about half that, the catch is, get a 54hz tuning, you can get twice the amount of sound waves in the same vehicle- due to the cone area radiating twice as fast as it does at 27hz, and more the likely about the same excursion.... kinda get how that works?