jessie.dazzle wrote:

Wow, 6 x 15" drivers (!!!); though the curved profile certainly imparts rigidity, I'm guessing this horn must resonate more than a bit (no bracing until the mouth) -- but I like this thing. Interesting, the phase plug-like device in the center. If ever traveling near these people I will definitely try to arrange a demo. About the idea of harnessing and trying to "tune" resonances... It reminds me of the "argument" that a flexible automotive chassis has merits (yes, perfect if you wish to "confuse" the suspension and fatigue the occupants! Never mind, I'm starting to sweat). I know, horns are not cars; apples and oranges etc. In any case, my instincts tell me that energy would be more properly channeled by allowing the excited medium in the horn (the air) to "work off of" a solid foundation (Ever stand on the top rung of a ladder and try to hammer in a 10-penny nail?). Also, I don't like the idea of a driver working in the presence of a secondary source of excitement, regardless of its phase; in this case, air in the horn re-excited by resonating walls, causing pressure to feed back to the driver (An exaggeraton : The pulsating pressure one feels when speaking into the rear of a fan) But this all just theory. Though I may be wrong, this is why I went the other rout and used a material that is really dead and heavy with loads of bracing.

I did not know that they use 6 x 15" drivers. This is what the big mouth comes from. To use many drivers is obviously not a chose. Looking at the midbass horn of other I constantly try to nails down what I would do if I go there. This horn is a nice illustration on my view. What I change? Obviously a single driver with 7’-8” throat. Use 7 sections instead of 6 sections. His would get rid of semi-parallel surface in horn, allows the horn to have much better coupling to side walls and eliminate an sharp angle on another horn’s side that in the case of 6 section would vignette the MF channels.

It is unquestionably that to use of dead and heavy material with lots of bracing is the way to do if there is an opportunity to do so. I question is there is another opportunity. Let pretend that we have heavily built 50Hz from 7” to 9’ form made from “dead and heavy material”. We are talking about a more or less permanent setting with each horn be let say 300kg-400kg or perhaps even less. Now let pretend an alternative version. We have the back chamber and the first 2-3 linear feet made “heavy” (let call it “base”) and then we have detachable, relatively light 7 leaves attach to the base. The 7 leaves might be made from wood of 3/4-1”” or architectural plasmas, or whatever… The leaves have little and accurate handled that extended inside of the horn and the through those handled we have tightening cables going. It might be one cable/cord/rod or isolated cables, I have no idea but the concept is that tightening the cable we have a change to dynamically compress the horn’s leaves.

Pretend we made the horn, installed it where it shell sit, let pretend that it is 50 to 180Hz horn. Then we take a sweep generator and begin to sweep the home, looking for the resonances. In this case we can objectively pick the resonances with stethoscope but we can also to evaluate how those resonances impact the auditable sound from the horn. Theoretically by tightening the cables/cords/rods it might be possible to manage resonances and to move them around, shaping up how the horn might response to sound. BTW, I have no idea if the concept would work but I do not see why it would not. After all the musical instruments are very light and the keys in them is not mass but well-managed propagation of resonances.  It however very much might not work for reproduction purpose.

jessie.dazzle wrote:

… This brings to mind the time I tried walking during a fairly serious earthquake, or trying to write a letter while riding in a car...

Actually it is very good association. In Zaratustra amplifier bias was made by the very same concept. It was the Newton's Laws of Motion in action. The similar idea might work in tuning bass horn. We can look even beyond that.

Back in my youth I was studying design of railway locomotives and I remember that they had one devised that highly attracted me – the antivibrator. Let live aside how and why it was used on locomotives and let to apply the same ides to our lightly-made midbass horn. Keep it not as the real pros but rather as brim-attack.

We have 7 light segments of the horn and they resonate, individually and together. In the end of each segment we hard-bolt the Aurasound’s Bass Shakers:

http://www.aurasound.com/public/bassshaker/frameset2.html

Each Bass Shaker sits begin some EQ, volume control and phase switch. Now we can do with the resonance of out horn whatever we wish… make horn form very cheap and light material… Theoretically, if it works then it open a new whole outlook at the “pain” of midbass horns. BTW, this idea I was playing with while I was thinking about my “Resonant Oops” concept…

Jessie, I agree in spades.  You could play around trying to "tune" that thing for the rest of your life.

But then, who is going to hear serious problems with something that was such a pain and expense to build and install?

More likely is that anyone who got that far would either hear it as "successful" or they would, indeed, continue futzing with the thing into dotage.

OTOH, better to wind up with this a dud than to have one end of the house cast in bad-sounding concrete...

I'm going to light a candle, right now, for all the giant horn builders out there...

Best  regards,
Paul S

Mining the site, as I often do, I turned up a link to this thread.

Anyone thinking of horn LF right now, please take a look at post #7, this thread. This is, according to my experience, the quintessential "home brew" "LF" horn. Need I say more?

People, this is no "gimmie"...

Paul S