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When many of your will experiment with building and listening your own horns and spend countless amount of time by sketching a configuration of your new horn assembly you then might come to an observation that Macondo Upperbass topology is very slick solution that is very hard to beat sonically and practically impossible topologically.  He key to everything is 4” throat that this upperbass horn has. The whole idea of Macondo is based upon that 4” throat.

If you go for larger driver, let say 12 or 15 inch then you can’t not use 4” throat as the compression will damage the small sounds. So, you do it then you end up with let say 6”- 10” throat. However the size of the Upperbass mouth is restricted by elevation of your MF driver that has to be more or less at easy level. If the bottom of your MF horn will be higher then let say 40” then whatever Haralanov’s “gravity” you will be using you will be forced to  till your head up to listen your installation. It is acceptable to a minor degree but only to minor degree. So, let presume that we have even an elliptical horn and small MF then we have let say 45” space for Upperbass that would make a nice 90Hz-100Hz horn. It would go bigger, to let say 85Hz, if you do non-spherical, if you like how they looks like. So, now we have a big mouth under your MF channel but the problem is that this big mouth projected to the big throat does not give to you necessary LF horn equalization. With 38” mouth that Macondo has and 4” throat the upperbass has 9.5 time size difference between throat and mouth. If you use let say a moderate 8” throat with 12” or 15” driver then in order to get the same equalization you would need 76” mouth for your upperbass. For sure you have no room to use that mouth and what everyone does is making mouth smaller, therefore reducing the horn LF equalization. As the result the LF does not produced as much by horn but rather produced by exertion of LF driver. Which is called a direct radiator operation: the picture does look like a horn but the horn equalization in such a horn is very inadequate.

On another side of spectra we can arm the Upperbass with super duper compression drivers from GOTO, ALE, YL Acoustic, Kondo or whatever else exotic it might be. They do spectacular compression drivers that have 70-80 Hz own resonance frequency. They do not have barbaric compression, they have phenomenal diaphragms and suspension, high sensitivity, and for all intended purpose they are the best in the game for this application. Let look for instance this driver:

http://www.hifido.co.jp/KWALE/G0205/P0/A10/E/0-10/S0/C12-70209-62522-00/

It is perfect and it costs near what it has to cost. The problem is that is has somewhere near 2.5” throat that would require not 38” long horn (now I am taking not about diameter but length from mouth to throat) but rather 2 -3 times longer. It would be superbly impractical to have 70-80” long straight horn and it would be absolutely impossible to time alight it. So, what people do is shorting the horn and doing for 1/8 or 1/16 of horns and running some VERY fast opening profiles.  This is not good as all those  GOTO, ALE, YL Acoustic, Kondo and other drivers are made to be load to very slow opening exponential horn and the do need a very strong throat reactance.

So, what I am saying is that 4” throat that Macondo has is a very intelligent balance between everything: esthetics, sound, system organization, configuration option and many other reasons.

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