[stereocilia]

Atlantic Technology is making big claims for their bass-loading arrangement.  I'm no speaker designer, but what I've gleaned from those who are tells me this is smart but hardly revolutionary.  What do think?

http://www.atlantictechnology.com/default.asp?IsDev=True&NodeId=158

Audioholics also comments:
http://www.audioholics.com/reviews/speakers/floorstanding/atlantic-technology-h-pas

[JLM]

The concept appears to be a mix of sealed and tuned quarter wave pipe (neither impresses me much but I certainly could be wrong).  As always hearing/testing is the bottom line.

[bummrush]

I have Clements speakers Phil Clements designed these.I never heard of Clements til a year ago. He has made speakers for at least 25 years.I'm pretty sure you can take his word . He also sells Sollus in wall speakers.I don't doubt a word he says

[Letitroll98]

Well, there's really nothing new under the sun.  The design is quite simple in concept, a transmission line (looks like quarter wave) combined with a Helmholtz resonator.  Additionally it looks like they've employed some damping at specific areas to tailor the response.  The combination should create a low bass bandpass over a prescribed frequency range.  However to make it work you'd need pretty tight driver tolerances and a talented designer in order to avoid a boomy, one note bass sound.  From the preliminary reviews I've seen online it looks very promising with everyone being very impressed.  Is this product in production?  I can't quite determine if it is from their website. 

[stereocilia]

As for production, I'm pretty sure you can get these from Outlaw audio.  Thanks for your thoughts: it seems that this is genuinely clever but not a completely different class of design.  It is not analgous, for instance, to coming up with a class D design in a world of A/B.

[Duke]

Real-world bass extension to 29 Hz and a 2.83 volt sensitivity of 89 dB from a 6 ohm, roughly two cubic foot box isn't at all far-fetched, so I think the claimed specs are not exaggerated.   Kudos there.

As to what's happening inside the box, my guess is this:  It's basically a quarter-wave line, and that internal chamber is tuned to eliminate a problem inherent in most quarter-wave lines.  What happens is this:  At the frequency where the line length is equal to one wavelength, the energy emerging from the line terminus is 180 degrees out-of-phase with the energy coming off the woofer cone, so a cancellation dip results.  You can see this dip in the published measurements of many transmission line type systems, like this one:

http://www.soundstagemagazine.com/measurements/pmc_gb1/

If we put a helmholtz resonant chamber inside the cabinet tuned to the frequency where that dip would occur, the backwave's energy at that frequency is absorbed so we don't get the dip.  Result:  A worthwhile improvement over conventional quarter-wave systems.

That's my guess, and if that's what it is, I give the designer (Phil Clements?) a big thumbs-up.  But I wouldn't grant him a patent on it because it's been done before.

[stereocilia]

It's nice to have insight from a real speaker designer.  Thanks Duke.

[Duke]

Stereophile reviewed this speaker in the September 2011 issue, and if you have access to it, take a look at the measurements.

The port's output is fairly broad-band (like a transmission line), but with a deep notch in the upper bass region, where we'd normally expect a transmission line's net system response to have that nasty cancellation dip (see the measurements linked to in my post above).  The net system response for the Atlantic Technology speaker is exceptionally smooth for a transmission line type.

Good job, Atlantic Technology! 

[bummrush]

Itwas a great review .I was hoping to see what one of the mags had to say about them.Looking forward to hearing a pair of these soon.