Speaker cabinet construction..

Few understand that a transmission line IS NOT simply a vented enclosure, and that a properly designed TL can afford some of the lowest distortion bass available. 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 bonded dacron, as in mine. This material is packed in deminishing density towards the end of the line, and turns the acoustic energy into thermal energy. In a properly tuned line, only very low frequencies exit the end of the transmission line and 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 woofer's cone as in sealed or ported enclosures. These multiple echoes color the sound and can only be eliminated in a transmission line enclosure(IF there is to be an enclosure at all).

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.

In toto, a well executed TL's extended low frequency response, lack of multiple echoes from the inside of the box, and elimination of wall resonance will result in a very low distortion, fast and extended low frequency system.

Seems many loudspeakers go more for WAF then performance and cabinet material choice show this.

Absolutely. That is fundamentally what the majority of audiophiles plonking down $5K on a showpiece really want. Most are not aware of the colorations and many prefer teh colored sound (what they are used to hearing and expectations are everything)

Ports are of use dont toss the babie out with the bath water.

For sure ports have their merits especially large ones tuned very low can add little coloration, however, if you want to get fanatical about coloration simply take a look at the ort response from prototypical small port bass assisted design speakers from most Stereophile measurement plots and you will often find what is audible port output (distortion above 1%) up as far as the lower midrange.

In the context of extreme measures to reduce cabinet distortion it makes sense to talk about ports also....so WHY does the article ignore this? IMHO, since none of the discussion is breaking much new ground, it seems to be a very selective discussion clearly intended to be marketing material couched as science and technology.

Shadorne,

That's quite a conclusion you've jumped to. Am I sensing a history with VSA? I think it's fair to say that a paper regarding cabinet resonances can be written without the inclusion of porting. That's a different can of worms altogether. Albert Von Schweikert is a very successful speaker designer/manufacturer and I for one thank him for taking the time to explain cabinet resonances in technical terms. Don't be surprised if you see the occasional technical paper from the likes of Dave Wilson or Alon Wolf, "couched as science" or not. Don't forget, these gentlemen must sell what they design and manufacture. If they choose to write a tech paper explaining why their particular design may be better than that of the next guy, then more power to them.

I think this is a mischaracterization of ported designs. There was a time that I was a sealed enclosure snob, and dismissed all ported designs as "boomy one-note bass." But over time the designers learned how to properly damp a ported enclosure, and today there are many ported designs that have stunningly clear, fast, articulate bass. Everything from Wilson comes to mind.

The Stereophile measurements sections of their speaker reviews display a measured cumulative spectral decay plot, derived by attaching an accelerometer to a speaker enclosure's side panel. As you can see, speakers that have enclosures specifically designed for resonance control are very low in panel resonances, whether sealed or ported. Examples include B&W 802D (matrix enclosure, ported), Magico V3 (baltic birch and aluminum baffle, sealed), WilsonSofia (Wilson proprietary mat'ls, ported), and YG Anat Reference II (aluminum, sealed).

The B&W, Wilson, and YG are incredibly inert, and at least two of them are ported. The Magico is sealed, but a little more resonant. The YG cabinet has no internal stuffing; yet cab vibrations are nearly unmeasurable.

It goes 'round and 'round and it all boils down to how to market a speaker?
Trust your ears, what Bell Labs discovered many decades ago, and take all the white papers out there and line your birdcages with them.
Again, trust your ears and not what someone is telling you you're hearing.