Since my new tweeter will be arriving in a month or so I am slowing completing the ideas of finalizing the frame of my Macondo. Whoever dealt with 4-ways horn-lodes know that framing of this thing is quite tough. It should be functional and none-abusive at the same time and it is quite hard to accomplish. Also, horns do feel the presence of frames and fewer frames is always better. A horn just handing in open air – is absolutely the best.

I really satisfied and very comfortable with the way how in Macondo upperbass horn and MF horn mounted. The upperbass horn sites in the custom profiled wood assemble, filed with sand. It is very firm, very heavy and it does perfect foundation for Macondo.

There is a custom fame made for MF. I spent quote a time to design and to make it. I find it quite elegant looking and very functional as it does allow the reflections to bypass itself and do not bounce them back. The MF horn is hard-coupled to the MF frame but the MF frame is decoupled form the upperbass horn and sits in the upperbass horn under own weight. To insult the injury I have 40 point lead blob sitting inside the MF frame. A tweeter will be sitting above and behind the MF horn, on own mounting harness. I do not have it yet but everything will be quite straight forward there…

So, the entire assembly is feely might be moved in it’s search of the  DPoLS (there are carpet sliders under the bass horn frame). However, the lower MF horn (LMF) screws the entire picture.

When I added the lower-mid-frequency channel - LMFC (or as I called it “the fundamentals channel”) I really did not want to put any frame in front of the MF of HF channels and I ended up mounting the LMFC from behind. It works very well sonically, but it makes the entire Macondo very-very difficult to move as now I need to move the Macondo assembly and then, separately, to move the tripod with LMFC, along with all that complex system of contra-weights and LMFC alignment.

So, my idea is to make the entire 4-ways Macondo to be uni-moble and still to keep all Macondo’s accomplishments not compromised. What I am thinking is to put under the bass frame a plate with harnesses to hold the bass frame. On the back side of the bottom plate I would have a shoe in witch I vertical profiled rod will go. This vertical bar will run all the way up and will be lying in the back of the upperbass horn.

It is very simaple to visualize everything form picture. I like the idea and the only concern I have is that the vertical rod (and partially if it will loaded is as it is on the last image) might bend or curve. Perhaps by selection of a correct profile for the rod or the rod’s material, I would be able to prevent curving but… still it will be ~7” tall – and will be caring quite a mass…. Perhaps I would come up with gaskets between the back of upperbass horn and that vertical rod that would allow to offset the rod’s bending and to keep the axe of LMFC channel parallel to the MF? However if the rod bends then most likely the depth of the banding will be changing with time… I need some consulting with metallurgists….

Thanks Mark,

I was rethinking it and I come up with something along with what I depicted below. The main vertical rod become a triangular monopod and it will maintain vertical position because it will have a second point of contact” it will lay ay the back of the upperbass horn. I think this solution is more interesting and very much accomplishable.
 

I made some further adjustments, added details to the tweeter and so on. It looks good. Yes, to make this sail will be complicated and price. Not to mention that the thing will be over 6 feet long. I will not start doing it until I have the tweeter in my hands. I need to consult my machinist and see what he will suggest.  As I feel it all will boil down to the selection of metal. If it were steel then it will be thin, perhaps 3/8”, heavy like hell and welded. If it were aluminum then it might be 2-3”, bolted from top and bottom and disassembleable. The good part about aluminum that I could use a 4” sheet and CNC it to make 4” at the bottom and I would say 2” at it’s top. I might be very cool looking. The only thing that I do not know if aluminum-make threads in the bold will be able to handle the pressure of that lever atop. Well, we will see what the specialists say. There are other options – there is architectural plasmas – they are very strong, CNCable and could go the job but they are way more expensive. An aluminum leftover sheet of 4” that I need will cost in my local metal supply shop around $300-$400, though the architectural plasmas of the necessary strength will cost over a thousand dollars…. Anyhow, will see. The more people I talk about it the more I learn and the more options become available….

I did some further thinking. I slightly modified the sketch, more or less reflecting the actually dimensions of the elements. The tweeter was too large and the upper horn was too small.  The current downing is more reflects the current Macondo fell.

I was trying to keep the depth smaller as the upperbass horn is too long anyhow. I think if I go for 8” vertical steel plate of 3/8 or ½ of inch then it will be manageable enough and not horribly heavy. The only thing is that I would like to have the frame dissembleable and detachable from the bottom plate (still to be very firm). So, if I weld-in 4 large cylinders at the bottom of the vertical panel, with steel threads and then tight them with bolds for the bottom then it should do. In fact all of this because not really complicated to render….

Well, this for the tip of multi-layering the vertical panel. I like it a lot. I will allow keeping the mild panel thinner and more “airy” visually. The total high of the thing will be not 8’ for rather somewhere slightly above 6’. Also, I review the way in which the tweeter might be mounted. Since it is HF transducer and since it will be made in the shape  “drop of water” (to minimize the off baffle reflections) I think the pedestal via which I was thinning to couple the tweeter o MF horn (pictures above) will not be an optimum solution. I less care about the reflection as the tweeter is line array and will have quite narrow verticals radiation but still, I do not like any baffle-like impediments near tweeters.

Yes, Paul you are right. In my chaise for “cosmetics” the economic aspect jumped out of my aim. The last design would require 6 panes for a par of the loudspeakers it is might be pricey. McMaster quotes a steel panel of 3/8” by 6” by 8” somewhere near $450. I can do twice-trice less expansive in a local Admiral Metal suppler, not to mention saving a lot on shipping of the things. Still, if you add labor and finish than it might be in realm of a couple thousands dollars at its best…. It would be possible to simplify the things as at the image below; it would require juts one panel per speaker. Still, I heed to expose all it to the objection machinist and see where it might go from there. Hey, where the Cogent’s Rich and Ottari’s Paul are when I need them, their input would be very valuable. Anyhow, I think I have enough ideas to wait until the tweeter would be done and then finalize the design. For now, I’m good with what I and you guys have came up and it is a good staring point to lay down the objective to the attention of the professionals. Later on I will make the drawing in the exact dimensions and my machinist will asses how much thinkers and support that vertical frame need to hang that “fundamental channel”

At the risk of overloading you... Here are a couple of quick computer drawings showing a version made from 2 inch steel tube... Material cost would be very low.

jd*

Wow! Thank you! What a brilliant idea to make the vertical poll not solid but to assemble it with triangular pipes of the different length! I love how it looks. (I think it was proposed before but I did not visualized it without image)

The only concern I have that the rectangular tubing available with .065" wall-thickness maximum and it might make the strength of the vertical panel not as effective. For instance on the drawing that you made the force of the upper horn sits juts upon 2 tubes and the shorter tubes do make as much support as it would be in case of solid plate. Sure, if it would be possible to hard -tight the tubes, like welded… but I still do not know how strong it would be. Surely I need some machinist to assess all of it….

hagtech wrote:

Romy, I don't know what it is, but something bothers me about the way the upper horn hangs.  All other drivers are supported from bottom, that one from the top.  This is just gut, but it doesn't seem right to me.  I get this sick feeling of wobble and resonance.  Perhaps merely irrational thoughts. Is there any way possible to offer a support from the bottom?  That is, without disturbing the gas field in front of the tweeter.  I don't think it is as much an issue of top or bottom as it is that large moment of inertia I see with the tall stand.

Are any ways to support the upper-horn from bottom?  There are 3 ways that contemplated in past. It was use of thin tripod-like tubing coming from the upper-horn all the way to the bottom (similar to what Avantgarde did). This would put the speaker inside a virtual pyramid. I do not like how it looks like, not to mention the presents of one and a half rods ahead of the tweeter. Another option that I contemplated was use of two sides, similar to what Cessaro GAMMA does. I decided do not do it as I would like to keep HF and MF horns as free-hanging as possible because I feel that proximity of any boundaries near horn mouth screw imaging. The third way that I was thinking was to make the tweeter and the upper-horn frame integrated.  It would require an enormously strong enclosure for tweeter and very-well designed tweeter-frame. I am not settled with tweeter, an nowadays a new custom tweeter is being built for me. Theoretically after I get the tweeter and if it will perform up to the demands then it would be possible to contemplate the tweeter-frame integrated design. Still, whatever it might be it should connect the tweeter from it’s back only… it is EXACTLY what I a doing now anyhow… so, I disregarded the idea of making Macondo as “a pyramid of the horns” and decided to hang my upper-horn.

Let look what we have as “the problems”. The upper-horn is 600-1000Hz, and it is a compression drivers…. means relatively high frequency, very low exertion, low mass, low inertia. The upper-horn I made think (as you can see at the picture in the beginning of the thread). It is approximately 30 pounds + ~12 pounds of the driver. Now, correct me if I’m wrong but as far as I understand it - any theoretical resonance-induced by swinging would act against the center of mass. The center of mass is far ways on the horizontal level that makes the total applied mass of the horn assembly way over 200 pounds. In the past, contemplating all of it I made soft suspension of the upper-horn in its horizontal arm. It was immense complex setting where the horn was handing on 2 rubber suspenders. Interestingly that the decupling produce ABSOLUTELY NO DIFFERENCES to the actual SOUND OF THE HORN and I decided to go for hard-coupling between the horn and the arm. I also trued adding the additional 150 pounds atop of the horn (5 bags of the led shots) and it HAD NO SONIC EFFECT…

So, what I concluded was that any resonances that might take place in the “handed horn” are imaginable or negligible.  At least so far I was not able to hear the problems attributed to the swinging resonance…. So, I do not care about it anymore, and unless I head something that I find is “not right” I will not dig deeper. Generally purring a statescope on the horn says a lot what is doing on… The “hanged horn” responses via statescope identically to the same horn sitting on carpet. So, as they say out of sight – out of mind….