Transmission line speakers!

bkeske,

I don't think that Vandersteen ever called any of his speakers transmission lines, and having a slot vent doesn't make them one.

mrdecibel,

The Khorns were nothing like a transmission line, they were just a horn loaded bass driver.

I started designing Transmission line speakers in the mid '70's. They can be real good for the money. These days I use a ported cabinet design because you can get a better final performance curve.

I own T+A Criterion 2100 TL speakers.  I believe all the T+A Criterion speakers are transmission line.    Very deep, natural and linear sounding bass for midsized floorstanding speakers.  Never boomy, even in my room with hardwood floors. 

If they are in your price range, I'd take a listen.  I think they have one of the best transmission line designs. 

@roxy54

bkeske,

I don’t think that Vandersteen ever called any of his speakers transmission lines, and having a slot vent doesn’t make them one.

Sure they have. It’s right on their web site, and in many reviews of the 1C’s over the years as well.

From Vandersteen’s web site regarding the current 1C’s (the basic design has not changed), and also include a ‘cut-thru’ photo as well, albeit not very detailed :

The Model 1Ci’s transmission-line port extends bass response while operating much closer to the ideal than any of the more conventional ported or passive designs.

I'm another fan of the acoustic suspension approach.  It's been ~50 years since I read the Thiele-Small papers, so please correct me if I'm wrong.  IIRC, ideal porting only extends linear bass response for something like 1/3 octave - 2 or 3 notes.  Below that, it drops off at 12 db/octave, while an AS design rolls off at 6 db/octave.  In addition to the rapid roll-off, ported designs also unload completely at their resonant frequency, resulting in wild, undamped woofer oscillation.  A TL is a modified port design.  Creating a longer, damped path to the port ameliorates some of the problems with ports at a significant increase in cabinet complexity and cost.

I am intrigued by passive radiators, which allow the use of the woofer back wave without unloading the woofer, but have never owned any.