Q: What is a transmission line enclosure and
why is it superior to ported or sealed designs ?
The transmission line speaker was first described and patented in the 1960's. In a
classic transmission line, the sound wave from the back of the woofer is channeled
down a long pathway filled with a fibrous bundle of wool or another synthetic material.
In a properly designed line, very low frequencies exit the end of the transmission line
that extend the low frequency response one half octave below the fundamental
resonance of the driver.
In a transmission line enclosure, the back wave of the woofer does not bounce off an
interior wall and radiate back into the room through the thin cone of the woofer as in
sealed or ported enclosures. These multiple echoes color the sound and can only be
eliminated in a transmission line enclosure.
There is no pressure in a transmission line to excite strong enclosure resonances. In
a sealed or ported box, enclosure resonances can usually only be controlled, not
eliminated as in a properly designed transmission line enclosure.
Together, the extended low frequency response, the lack of multiple echoes from the
inside of the box, and the elimination of wall resonance account for the extremely
clean, well controlled and powerful sound of a properly designed transmission line
speaker.
"Boy, you turn your back on a Panga for a second and ..."
Dr. Bambamba relating last words of expedition leader to Africa
- Dr. J. Usta Snack
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