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Yes, it turned out to be the emails from GOTO importer. I am not completely understood if the horn at the picture above is an official GOTO product. The Ming Su said that the horn was build locally by Jeffrey Jackson with the support of GOTO but then he said that “This is the largest horn that GOTO can provide”. It is not exactly clear to me if it was hit personal journey or it was GOTO objective to develop a commercial product. 

Jeffrey Jackson wrote:

and as partial payment on this commission I received some drivers... so I look forward to trying dofferent horns with them... it should be fun.. :^)

Jeffrey Jackson wrote:

for Ming I built this horn to a combination of GOTO and my thoughts... Ming wanted to pursue what GOTO recommendation of 2:1 mouth ratio.. I like 1.6:1.. but that is a minor detail...the flare is GOTO’s hyperbolic... 60 Hz was chosen as largest full sized mouth that will fit in the room vertically... beyond this, the length also gets to be an issue.. we just figured build as much as you can fit that is properly built... try not to compromise the horn by shortening or shrinking the mouth...

Jeffrey Jackson wrote:

construction is all baltic birch.... the sides are three straight sections.. three step approximaion... the top and bottom are curved to match the exact flare... sides are 2x 3/4" sheets laminated together to form 1.5"... the top and bottom are six layers of 1/4" laminated to again for 1.5".... the only area that required extra bracing was right at the mouth on the long side... here I used steel "L" channel.. the curves of teh top and bottom really help keep them stiff...

Jeffrey Jackson wrote:

the system still needs to be played and tuned, but I can honestly say that I heard detail in the bow/cello inteface that I had never heard before...

Jeffrey Jackson wrote:

bass will at first be dual goto 15" per side in a large sealed box below the horns... Ming is also contemplating a single fold 18 Hz bass horn... the midbass horns would have to be turned sideways and set upon the new basshorns... we'll see...

Anyhow, Jeffrey, nice project, congratulation to you and to Ming Su. BTW, Ming said that we know each other via previous purchases a few years back. In any case I would like to take illustration of this midbass horn project and pass some of my attitude about the midbass horn.

The midbass horn is a pain in ass, a big pain!!! The GOTO-Jackson horn went for the very noble small throat size – something that I advocate for a long time and something that horn public does not buy yet. Sure the horn’s length is the punishment in the case of small throat size but it is what it is and if you do not like it then use direct radiator in bass-reflex enclosure. I do not support the GOTO idea to load two drivers in the same throat. I believe the idea is very moronic as it compromise unanimity of excursion. I understand that GOTO are willing to sell more drivers but still… The tandems of compression drivers were used in 30s-60s but primary to pump up pressure. It is absolutely not necessary for home use, not to mention that the person who can afford the constriction of the midbass horn like this and it’s positioning of pair of those monsters in his listing room would most like can afforest a dedicated amp to drive the midbass channel

Where the GOTO-Jackson horn shines is in GOTO recommendation to cross the 60Hz horn at 70 cycles. I do not know if it is the GOTO drivers cannot handle lower or any other reasons but it is very brave statement and I appreciate the GOTO honesty about it. Admit, no anyone would agree to lose 10Hz voluntary (and whoever played with it know that 10Hz in midbass horn is a LOT). Still, I feel that in the given GOTO-Jackson

case we have in the situation when GOTO works against Jackson. Let me to explain. The Jackson’s horn has 60Hz mouth but the back chamber of the GOTO horn is apparently too large to deal with the Jackson horn throat’s reactance. So, GOTO, instead of minimizing the size of the back chamber and raising the resonance frequency proposes to raise crossover frequency. What they do eventually is undermining the 25% of the Jackson horn by bounding this horn to the default GOTO drivers (that was one of the reasons why they when for tandem of drivers). Let for instance drop loyally to default GOTO drivers and to see what is necessary in here. If the GOTO driver can handle the LF extension and operational power with reserve then it is necessary to decrease back chamber of the driver, making the driver’s resonance to “hit” the horn’s rate. At that moment the damping of the driver cone will be kicking at the very same time when the throat’s reactance will jerk the driver’s cone. That would allow this horn to operate down to 60Hz easily and the more important to be able to pass a few DB more equalization at 60Hz. In that case the driver should be crossed at 30-40Hz to keel Doppler ghost and other ghost out of the mouth of the horn. However, is GOTO willing to play with the driver? Hmmm… it does not look like they do.

The next thing is the … stupid, stupid… the needs of the horn. Looking at the picture how this horn is being used I would very much not welcome the idea of such a horn. We do not know how to time alight this horn – it is given and it is said, still it is not my primary concern. My primary concern is that many people are losing a perspective confusing between building a horn (or an amplifier, or a tonearm, or a whatever) and building Sound in listening room. Why is it so bothers me in context of this midbass horn? Because trying to implement his inhalation around this upperbass horn Ming Su end up with the following:

I have to note that it has very little in difference with any other GOTO inhalation I have see. I head only two GOTO installations and then was the same: a pile of horn dumped in brainless cerotic order. In case of this monster properly dimensioned 60Hz horn the situation even worse. There are absolutely no options (in my mind) to position this horn at floor. Let pretend that the horn is high-passed at 700Hz. Then with horn minimum dimension of 45’’ we have 20” MF horn that makes the minimum axes of MF at 55” from floor.  It is too high and it will set the minimum listing distance at 15”. There is another problem with this setting. The LF will be radiation from very wide position of horizontally placed midbass horn, including form the middle of “stage”. It is not good as LF coming from the space between MF screws up imaging very severely. The only solution is to have an incredibly wide room…

Still, there is a better solution that I always pitch as the “ultimate”: to mount the midbass horn to sealing.  By doing it there is more opportunity to deal with time alignment. It is possible to hand the midbass horn in open air, the way how Jessie would like to do it. It will work very as well, but coupling midbass to sealing (surface) will yield extra 1-5dB that are so welcome at 60Hz. Sure, it all should be look in context of “everything” else…

In the end the GOTO-Jackson horn is a wonderful horn but I doubt that at this point is made an interesting GOTO-centric installation. If Ming Su’s objective was to build better own playback than I feel he needs to work on it more and this current state is just a transition for him. The attempt is very noble though.  If the objective was for GOTO to demonstrate that they “can do it” and “here is out new model” (in the same way how the paintings of some conceptual artists are reproduced) then I think they need to work more to see how to USE this drivers. I understand that it very simple to make the back chamber of match to the given throat’s reactance but GOTO do complete drivers. So, they apparently propose to match horn with specific cone’s dumping of a given driver cone and if not then to roll off the driver electrically. Hmmmm, I do not like it. I would rather prefer GOTO to introduce a set of enterable gaskets that would minimize the back chamber size.

Another interning alternative would be to driver suck a midbass with SET and try to find a “right” lording for the driver cone given the specific throat reactance. However, I it possible only if the midbass horn work is relatively narrow bandwidth that does not look like the case in the Ming Su’s situation….

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