TL length question

[theChris]

ok, the situation is that my 12" woofer in my car broke, no voice coil damage or anything major, the glue used by the manfactuer has been having issues...

in anycase, i have only 2 6.5" peerless CSCX (4ohm models) to use as a replacement. i had wanted to try a TL type enclosure. but the Fs of the 6.5s is pretty high, 50.7Hz. this worries me. if i make the line longer then 1/4 wavelength of Fs what will happen? will it be tuned lower, giving a low frequency boost? or will it completely destroy the TL design?

i could use the woofers in a low tuned ported box as well.

i don't plan on this being perfect or permanent. at most until spring.

[theChris]

also, why is the opening placed on the opposite side as the speaker?

[planet10]

The effective length of the TL should be no longer than a 1/4 wavelength of the Fs of the driver. if it is longer you will typically get less bass.

The effective length is determined by the line taper. The positioning of the terminus is flexible -- it all depends on the folding you use.

dave

[Timn8ter]

Would it be better to face the port away from the listening position in this case since we're dealing with close proximity and high tuning? Don't want those mids messing things up.

[GM]

>Don't want those mids messing things up.
====
What do think the stuffing's for? Vent position is a matter of convenience or for boundary loading.

GM

[Timn8ter]

What do think the stuffing's for?

DOH!

[Bose(o)]

Instead, a 3/4-wave transmission line design is employed and efficiency of 95dB is attained. Generally, a 1/4-wave transmission line design is conventional. Warren Gregoire and Associates chose to use a 3/4-wave design to extend the useful low end to a claimed 30Hz.

-tnt-audio.


....If you've got room

[MJK]

That designer has no idea what he is doing. A 3/4 line is nothing more then a 1/4 line tuned way too low. He wasted a lot of space for probably sub-par results. Looks the designer also sucked tnt-audio into believing some real voodoo.

[planet10]

I too was going to comment of the 3/4 wl TL.

Any open ended pipe resonants at a 1/4 wl (a closed one at 1/2 wl). Doesn't matter how long you make them, this is the physics.

dave

[Timn8ter]

I found this statement in the referenced article interesting.

The Ikonoklast speakers seemed to be at their best in a small room, with nearly square dimensions and a low ceiling. They also seemed to sound best when played at relatively low volume.