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Horn-Loaded Speakers
Topic: It's the horn not the driver!

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Posted by Romy the Cat on 11-19-2007

A visitor of my site, presumably it is someone from GOTO, sent me email informing that GOTO made a new midbass horn. My enthusiastic applauses to GOTO as former GOTO bass-horns were  very bad and not serious.

http://www.goto-unit.com/3.html

Pull out the images form the bottom of the frame.

GOTO_Horn.jpg

The horn has 90” x 45” mouth and 100” long. The horn rate is 60Hz and it is croosovered from 70Hz – VERY interesting peculiarity. The price, materials and the throat size is not know yet.

Bravo, Goto!
Rgs, Romy the cat

Posted by Jeffrey Jackson on 11-20-2007
hello again Romy, cats, friends...

I built this horn for Ming Su, the Goto USA importer... I have posted on your site before about midbass and bass horns... I listen to eight foot straight 45 Hz horns... 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.. :^)

for Ming I built this horn to a combination of Goto and my thoughts... Ming wanted to pursue teh 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...

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...

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...

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...

Peace,
Me

(I know that I am a manufacturer, but I am one who only makes a few things a year and custom per the customer's request.. so maybe not so bad?)

Posted by Romy the Cat on 11-21-2007

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.. :^)
It would be very interesting to learn what you think about them. BTW, might I ask you what is proximate commission cost of the entire project of building the pair of horns like this, ball park…?
 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...
The hyperbolic? Hm, OK…

 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...
Might I ask you what was the size of throat of the horn. I always surprise what people talk about horns and forget the motion the throat size. It is possible to calculate it from the length but I do not want to dive in math…

 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...
…and how the everything else?

 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...
The single fold 18 Hz bass horn...Well, I do not know… should I ask about the “everything else”?

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….

Rgs, Romy the Cat

Posted by Romy the Cat on 11-21-2007
With Ming permission I post a fragment of his emails where he describes his midbass horn. It appears that he uses cone-drivers with ltooooooo ow Fz in non-compression application with no back chamber. Now it is obvious where he is losing his midbass response and where his horn underperforms. I extend to much credits for the “GOTO design efforts” :-). Also below is the PDF file with GOTO driver specification to understand what Ming is talking about.

After my visit to Japan last year and heard the GOTO bass horn myself, I started to plan on my own bass horn system.  However, due to the size of my listen room(16x25x9 ft WxLxH), I have to limit the size and cutoff to 60Hz.  Finally, I decided to use double driver per channel to reduce the length of the horn and that make it possible to fit such 60 Hz horn into my listen room and still have enough room to listen to music.

BTW - I will use double GOTO 15" woofer in a bass reflex box for 70Hz down.  Also, maybe going for the 18Hz bass horn later.

GOTO has never build any production horn lower than S150 horn because any horn lower than that it is not possible and sensible to build at GOTO and then ship or move.  GOTO does provide all technical support and information to help the customer build the horn.  The customer has to find local contractor or builder to build their own horn.  In my case, I ask for Jeffrey Jackson's help to build this 60Hz midbass horn.  GOTO does supply the twin throat adapter and will also provide the specification if one want to build their own.  Attached for your reference.

Of course, if any US customer want to also building bass horn using GOTO driver, I can provide a turnkey project but the cost will be very high as you can image.

I build this 60Hz horn based on GOTO SG146LD4 bass driver specification and the space limitation of my room.  The same GOTO driver has been around for many years and most of people use it to cover 200Hz down to 20Hz.  I intend to use this midbass horn to cover 70Hz to 270Hz in a 4 way system.  The rest of my system will be a new SG5880S to cover 270Hz to 5kHz and a new SG188S tweeter to cover 5kHz up.  The dual SG38WNS 15" woofer in bass relfex cabinet will cover 70Hz down.  Still thinking of using dual 15" GOTO woofer in a single folded 18-20Hz horn if my room have space for it.  Jeffrey is still working on the design but won't be ready until late next year if I decide to go for it.

http://www.goodsoundclub.com/PDF/GOTO.pdf

Posted by MINGSU on 11-21-2007
Hi All,

This is Ming Su and I am the US distributor for GOTO and J.C. Verdier. 

I thought that I will share with you about my new midbass horn.  As you know by now, Jeffrey Jackson from http://experiencemusic.net/ help me on this project.  We built this midbass horn based on the specification supplied by GOTO.  The SG146LD4 driver can play down to 20Hz but we choose to crossover the horn at 70Hz only due to the space limitation of my listening room.   GOTO provide the twin throat adapter and the 1st section of the throat/horn.

I don't know if the SG146LD4 should be classified as cone-driver or other type of driver so I have attached some picture of the driver with my posting.

I am heading to Japan tomorrow to visit GOTO again to audition some GOTO basshorn setup.  These users who built their house around the GOTO bass horn - some use the same driver like mine, the SG146LD4 bass driver, and some use SG38WSSP, the 15" paper cone driver.

Have a nice Thanksgiving holiday,

Ming

Posted by Jeffrey Jackson on 11-21-2007
Hello again, Romy.. let me see if I can clear some of this up....

first, you are indeed correct on your horn thoughts.. but some clarification is in order...

Ming Su is the importer of GOTO to the USA... Goto Japan only ships horns from flare frequency 150 and up... if you want something bigger, they offer assistance and drivers...

they do this for the very reasons you state.. such a horn really has to be considered in the context of the room and with the whole of music reproduction in mind... large horns require much thought... Ming would like to provide this custom basshorn service to his customers in the US market.. Goto Japan has nothing to do with this...

Ming is relatively new to this art of horn building... he has heard quite a few Japanese systems.. he has heard many traits that he liked.. afer living with compression driver top end and GOTO 15's in Onkens to cover 300 and down, he really wanted to try horn loading lower... I have built quite a few such horns and some friends connected us...

he has listened to Goto's advice quite a bit.. they have very strong thoughts on how to do things... some you will find humorous, others you will agree with... they beleive that electronics don't really matter.. the driver is the primary importance above all others... to them, it is silly to buy expensive electronics if you do not have double drivers on all your horns.. (I do not believe in this, at all) .. they also do not believe in time alignment... I have heard the amazing transformation that time alignment brings, both with digital correction and with physical alignment... Goto says the drivers can just go anywhere.. their philosophy is that a low distortion loudspeaker is the most important thing...

double drivers... I am with you on double drivers... I understand that it shortens a horn.. to me, that is usually a bad direction.. length helps with loading.. especially in the lower frequencies... (at high frequencies I tend to like short horns, subjectively)... I also find that double drivers in the mids and up confuse things a bit.. a touch "blurry"... but I must say that I know two people who liked double drivers in the 300 to 1500 range better than single.. do note that both have *large* rooms... also note that Ming'shorn has adequate length at over 8' for a 60Hz flare...

so Ming's system... I think he will get "there"... he has several options.. locate the 300 cycle horns in the mouth of the midbass horns... flip the midbass horns sideways to the floor and then position the midhorns above the midbass horns... third, place the midbass horns sideways along the ceiling and use low basshorns below... 300 cycle horns could go into the low bass horn mouth...

as they are, if the 15's in boxes go below the dual compression drivers, at least those two would be very close in alignment...



so what have we skipped.... the rear chamber and reactance annulling... yes, I know this subject very well... it makes a very audible difference... and deserves our attention... Bell Labs actually published a formula for source impedance with regards to horn impedance.. it was quite enlightening.. they used very high output impedance amps with their horns... and, yes, they had *giant* aluminum diapragmed compression driven bass horns... interesting, no?

hyperbolic is just a slower starting exponential.. it is what goto favors.. you can cross closer to the flare frequency with this expansion.. it loads the driver very well down low... as an example, my goto 150 horn with single SG505 is 50 inches long! this is well over a half wavelength at 150Hz...

the throat of Ming's horn is two times 100 mm diameter openings, I believe... I did not build the dual throat adaptor.... the drivers are quite impressive in scale.. the pictures make them seem smaller than life... but I do wish we could have the rear chambers modified for the task, as you pointed out... Goto, as far as I know, does not do this for any of their horns... for each driver they sell a few different size horns.. and no changes to teh driver... :^(

cost for such a project varies widely... this one required hiring help as the individual pieces were too large to carry with one person... in standard black finish (actually three coats of stain and paint) it would be about US$15k... this includes delivery and setup in the continental US... moving to even a 70 Hz horn would drop the price significantly... adding veneers would quickly raise the cost...

I am working on a LONG ceiling mounted straight horn for a Cogent large driver.. still planning stages only, but I cannot wait to hear it...

I would recommend this construction method to any DIY'ers, but just be forewarned that it takes *lots* of time to build in this method... I used up nearly 40 sheets of 4' x 8' plywood in this construction... so just moving the panels is work...


hmmm... and Ming's email to you... I think you guys had a miscommunication... Ming will not be using any cone drivers on this horn... if we build a horn for the cone drivers, then it will be for use from 70 down and properly tuned...

anything else I missed?

keep pursuing the sound!

Peace,
Me




Posted by Romy the Cat on 11-21-2007

 MINGSU wrote:
The SG146LD4 driver can play down to 20Hz but we choose to crossover the horn at 70Hz only due to the space limitation of my listening room. 

Ming, here is the whole point. If the driver meant to be play20Hz then it has most likely resonance frequency somewhere near or sub 20Hz. This type of the driver will have VERY difficult time, if it any possible to deal with throat reactance of the 70Hz horn. You would need to use there a driver with 40Hz -60Hz of primary resonance. If you do so then will be able to use the full mouth of your horn and do not cut it off 10Hz ABOVE the horn rate.

 MINGSU wrote:
I don't know if the SG146LD4 should be classified as cone-driver or other type of driver so I have attached some picture of the driver with my posting.

Actually it is very interesting driver and it looks different then I tonight. I never had GOTO driver in my room so it is difficult to be to say but it looks like 4” exit and titanium cone. They mostly likely vented it for 20Hz in the space across magnet, using the Audio-Technica venting methods (with felted ports). You might find out how they did it and you might alter the back chamber for have higher resonance frequency. Who knows – it has very light cone and you might be able to increased the driver’s resonance frequency 3 times from where it is now – then you will be able to load your horn with full mouth… and you will have “different type” of midbass…

Rgs, Romy the Cat

Posted by Romy the Cat on 11-21-2007

 Jeffrey Jackson wrote:
Ming would like to provide this custom basshorn service to his customers in the US market.. Goto Japan has nothing to do with this...

Very cool, the more “hornier” the better as far as I concern.

 Jeffrey Jackson wrote:
Ming Ming is relatively new to this art of horn building... he has heard quite a few Japanese systems.. he has heard many traits that he liked.. afer living with compression driver top end and GOTO 15's in Onkens to cover 300 and down, he really wanted to try horn loading lower... I have built quite a few such horns and some friends connected us...

Yep, the Onken loading will do it.  I heard it is what Germans was listening before they attacked Poland… :-)

 Jeffrey Jackson wrote:
he has listened to Goto's advice quite a bit.. they have very strong thoughts on how to do things... some you will find humorous, others you will agree with... they beleive that electronics don't really matter..

…and they are absolutely correct.  Electrons do not exist and they were invented by American colleges to change those exuberant amount if money for bogus education.

 Jeffrey Jackson wrote:
…the driver is the primary importance above all others...

Very enthusiastically agree but there are so many “buts” that they mane the statement ridicules..

 Jeffrey Jackson wrote:
… to them, it is silly to buy expensive electronics if you do not have double drivers on all your horns.. (I do not believe in this, at all) ..

Vladimir Lamm, the chef-designer of Lamm amplifiers told one to one of his customers that he need to buy each few years a new amplifier from Lamm because the older amp have has parts worn. I wonder of Lamm and GOTO come from the same direction…

 Jeffrey Jackson wrote:
  … they also do not believe in time alignment... I have heard the amazing transformation that time alignment brings, both with digital correction and with physical alignment...

Yes, I know about it - they are idiots in this subject and it is very obvious from any single GOTO intention I heard/seen.  I religiously refuse to even to think about horns if they are not meticulously time align. The problem with GOTO is not they are not “just wrong” but the problem is much larger in caliber. Making statements about this “believe they have” they indicate to me that they have no serious experience in any listening assessment and in Sound reproduction. To me it is severely compromise any other statement they make about Audio.

 Jeffrey Jackson wrote:
  Goto says the drivers can just go anywhere.. their philosophy is that a low distortion loudspeaker is the most important thing...

I disagree with it. A compressing driver is not a serf-contained stricture and it might be viewed ONLY in context of loading it into a horn.

 Jeffrey Jackson wrote:
  double drivers... I am with you on double drivers... I understand that it shortens a horn.. to me, that is usually a bad direction.. length helps with loading.. especially in the lower frequencies...

Especially in the lower frequencies? Congratulations, you understand horns more then 99% of people who do them.

 Jeffrey Jackson wrote:
  I also find that double drivers in the mids and up confuse things a bit.. a touch "blurry"... but I must say that I know two people who liked double drivers in the 300 to 1500 range better than single.. do note that both have *large* rooms... also note that Ming'shorn has adequate length at over 8' for a 60Hz flare...

That why I was surprised about the double drivers. The Ming's horns do adequate length and it should not be cheated by the double drivers

 Jeffrey Jackson wrote:
  …so Ming's system... I think he will get "there"... he has several options.. locate the 300 cycle horns in the mouth of the midbass horns... flip the midbass horns sideways to the floor and then position the midhorns above the midbass horns... third, place the midbass horns sideways along the ceiling and use low basshorns below... 300 cycle horns could go into the low bass horn mouth...

Yep, I would hang the midbass above and as you said put an upperbass on a floor to anchor the center image. Something similar to what Jessie is going:

All_Wire_CompV_01.jpg

 Jeffrey Jackson wrote:
  so what have we skipped.... the rear chamber and reactance annulling... yes, I know this subject very well... it makes a very audible difference... and deserves our attention... Bell Labs actually published a formula for source impedance with regards to horn impedance.. it was quite enlightening.. they used very high output impedance amps with their horns... and, yes, they had *giant* aluminum diapragmed compression driven bass horns... interesting, no?

I do not use formulas, I do not know them. Here is what I use:

http://www.goodsoundclub.com/Forums/ShowPost.aspx?PostID=2991

 Jeffrey Jackson wrote:
  hyperbolic is just a slower starting exponential.. it is what goto favors.. you can cross closer to the flare frequency with this expansion.. it loads the driver very well down low... as an example, my goto 150 horn with single SG505 is 50 inches long! this is well over a half wavelength at 150Hz...

The hyperbolic and exponential should give “more bass” but less quality and LF “noise” then … Tratrix-like profiles. I have personally no experience to make this statement but I juts repeat the words of the reputed by me people who have built both profiles with the same rate and compared the results. I still feel that ether hyperbolic or exponential should be more fan then ….direct radiator…

 Jeffrey Jackson wrote:
  cost for such a project varies widely... this one required hiring help as the individual pieces were too large to carry with one person... in standard black finish (actually three coats of stain and paint) it would be about US$15k... this includes delivery and setup in the continental US... moving to even a 70 Hz horn would drop the price significantly... adding veneers would quickly raise the cost...

It is somehow how I expected, are 4 drivers included in the $15K? :-). I have my design of my 55Hz-60Hz horn for years; I have the “prepared” drivers and all ready to go. If I found a good incentive to get a larger place then I would go for it… I estimate that it would cost me ~ $10K unfinished.

 Jeffrey Jackson wrote:
  I am working on a LONG ceiling mounted straight horn for a Cogent large driver.. still planning stages only, but I cannot wait to hear it...

It might be interesting project post some ideas if you wish, perhaps in another thread.

The Cat


PS: BTW, I visited your site and realized that I have seen it before. When I searched my site and guess what I found?

http://www.goodsoundclub.com/PopupEmail.aspx?PostID=5202

Posted by Romy the Cat on 11-23-2007

Ming,

I was thinking about this SG146LD4 driver again. They say: 106 dB/ 20 - 500 Hz, 19,000. Well, let look at this a little bit further as I feel that might be very interesting driver.

I admit I never heard about this driver. All that I know about Got was from here: http://www.eifl.co.jp/index/goto/goto.htm, where the SG146LD4 driver was never mentioned.

So, the SG146LD4 is driver that GOTO clime might work down to 20Hz. I think they slightly fool of it and it is … very good. Considering the side of the driver and a few other things I presume that it might be a 40-60Hz driver with reasonable primary resonance of ~50Hz -60Hz, or even twice higher. Making the climes that this is 20hz driver was foolish for GOTO as then turned off many perspective customers that might find this driver worth of their interest. GOTO did not lie; you can push 20Hz out of this driver. The driver looks like has 4” throat and if someone decided to run fill 20Hz mouth from 4”  then it will have tremendous horn equalization, I would say it will have +12dB -18dB at bottom, or perhaps even more. Sure it will be 50-70 feet long but it is not my main point. My main point is that 20Hz application of this driver is not something that should be advertised. Such 70 feet 20H horn will have a super high throat reactance and I down that the driver is optimized for that duty.

I intentionally write it while you are in Japan visiting your GOTO folks because they need might like to review what they say about the driver and some other things. If I were a perspective customer then the very first question I would ask myself if the driver might be optimized for MY GIVEN HORN. A MF drive might be with fixed compression ratio and fixed back chamber as using it in 1000Hz horns or 700Hz horn make lilt difference. However, with midbass driver is very different story – in such a driver the volume of back chamber is the key for proper driver to horn interface. The GOTO folks if they are intend to sell those drivers to horn people who have brain, experience and ears (me for instance) shell make the back changer of that driver adjustable or tunable with publishing the available open air resonance frequency for max and min chamber.

If GOTO folks with I can pitch a few ides how it might be done with “back chamber bleeders”. I think, what you are there you might talk to them about it. I well understand what GOTO is trying tom do – thy try to use fixed back chamber and to deal with throat resonance by multiplying drivers. I can give many reasons why it is wrong direction in attempt to match driver to horn.

So, what I would like to see is GOTO converting SG146LD4 driver into the SG146LD4 with variable cone damping. You, as a distributor will be benefited as well as it would make the SG146LD4 more attractive for perspective users.

Rgs, Romy the Cat

Posted by MINGSU on 11-24-2007

Hi Romy,

I spoke to Mr. GOTO about your question today and he told me that the reasonance of SG145LD4 is at 24Hz.  If customer want to build a 20Hz, he will recommend to use at least 2 driver per channel but best to use 4 driver per channel to shorten the horn length.  I visited a GOTO customer today who use two SG38WSSP(the top of line GOTO 15* woofer) per channel on a ceiling bass horn of 28Hz cutoff frequency.  It is not a 20Hz horn but sounds very, very good.  Mr. GOTO said, if this customer use 4 driver per channel, he can certainly build a true 20Hz horn.

I guess that you are right about using single driver for a 20Hz horn is not a real practical application, even it is a GOTO driver.  Most of GOTO bass horn customer use dual driver per channel, only two GOTO user use quad driver per channel for bass horn.

Will post more infomation and pictures after I retrun back to USA.

-Ming


Posted by Romy the Cat on 11-24-2007

Ming,

thank you very much for resonance information, it explains a lot about the SG145LD4’s suspension. Still, my primary interest was not how folks out there build 20Hz of 24Hz horns but about ability to use the SG145LD4 properly for smaller horns, for instants for 60Hz horn like your or for 100Hz horn like mine. To do so the driver should have much higher resonance frequency and I do not know if the driver would allow it. Would you please ask Mr. Goto if his SG145LD4 driver has an ability (intrinsically built or obtained by gasketing or padding) to modify the volume of the driver’s back chamber? It would be absolutely fantastic if the driver would have interchangeable diaphragms and the higher resonant frequency diaphragms were available with this driver. Still, to dial-in the driver precisely to a horn the methods of back chamber’s control should be available. Also, what is the retail price of the SG145LD4 driver?

Rgs, Romy the Cat

Posted by MINGSU on 11-24-2007

Romy,

I am off to Taiwan tomorrow but will ask the question by email.  I have not heard that kind of custom diaphragm ever available from GOTO on SG146LD4 driver.  I know the 15" woofer can be request with different stiffness of the cone.  The SG146LD4 is recommended for 20-500Hz but the driver is well entended to 1k but is not recommended to be used with crossover higher than 500Hz.  Most users use it for 200Hz down to 10 Hz above the horn cutoff frequency.  I do have some good recommendation from Mr. GOTO on the placement of my midbass horn which I will try after I return.

FYI - The SG146LD4 MSRP is USD$20k each.  
 
More after I return back,

Ming


Posted by Romy the Cat on 11-24-2007

 MINGSU wrote:
Most users use it for 200Hz down to 10 Hz above the horn cutoff frequency.

Ming, I do not think you are “getting” what I am trying to say.  OK, let to make bold statements: the people who use the 24Hz SG146LD4 driver from 200Hz to 10 Hz do not use it properly and get compromised results compares to what they might get from their horns, including you. The way how Mr. Goto suggest to use his fixed low-resonance driver with ANY LF horn and then “cure” the horn choking by introducing the “above the horn cutoff frequency” is fundamentally faulty. Frankly speaking it screws up the user of the driver as the are loosing 20-25% of this horn size, not to mention the quality of base notes. What you get home read careful what I said in this thread and in the linked threads. You might make some own experiments with own light prototype horn learning how change of the horn-driver resonance relation might very dramatically change sound of the bass reproduction. The $20K is quite a lot of money for the drivers and people should get a proper result for this money instead of a generic cookie-cutter solution.

Well, it is given that it goes along with my general attitude toward to “GOTO ways”. To demand from a company that does not believe it channels’ time aliment to discriminate the change of bass quality with driving the resonance frequency up it might be too much to ask. For a time being I will leave you with fact that your midbass horn produces 15-20Hz less then it should and it has was less sophisticated bass then it may have. To listen Mr. Goto recommendations about the horns placement in context of everything else is like to have harshly clipped power in mains and try to “cure” it with “better” power cord…

I just hope someone would educate Gotos on the subject…
Rgs, the caT

Posted by jessie.dazzle on 11-24-2007
Romy wrote :

"...The horn rate is 60Hz and it is croosovered from 70Hz – VERY interesting peculiarity..."

And

"...Where the GOTO-Jackson horn shines is in GOTO recommendation to cross the 60Hz horn at 70 cycles..."

I would have thought this crossover point to be WAY too close to the horns cut-off frequency.

???

jd*

Posted by Romy the Cat on 11-24-2007

Yes, I was not able to decipher right the way why they did it. My initial feeling was that they made PROPER horn and use a PROPER driver and then, because the approximation of cut off to horn rate they had audacity to cut off the response on the horn. It would be VERY interesting and very commendable. Not a lot of people would have balls to do it on 60Hz horn. However, since I learn the driver (drivers!!!) that were use in this horn I do know that they juts truncated the response of the horn because the driver does not match the horn and has way too easy cone feedback to the horn’s throat reactance.

 jessie.dazzle wrote:
I would have thought this crossover point to be WAY too close to the horns cut-off frequency.

Yes it would be true for higher cut off horn but would it be the same for 60Hz horn? With lowering frequency the rules of proximity change and I do not know the progression. At 7kHz you would need a cut off ~2 octaves below the horn rate. At 1kHz you would need ~1 octave. At 300Hz your might sometimes go away with slightly more than half octave. How this work at 60Hz? Will it be linear dependency or logarithmic? I thought to observe how GOTO think would be educational, but it was not as they juts fixed problems with high cut off.

The biggest questions of all would be if loosing of 10Hz would be worthy then to apply many other things that might be done. I personally if I go for 60Hz horn would drive it with 30Hz crossover (juts unloading the necessary excursion form the horn as I do in my upperbass) and then use back chamber and damping from amplifier would try to write up the proper bass structure.

Rgs, The Cat

Posted by Jeffrey Jackson on 11-24-2007
Hello again, Romy...

I totally agree with you about changing the rear chamber volume. It makes a very positive improvement in extension as well as quality. Also, I had never dreamed of a driver with a variable compliance resulting in a variable free air resonance... such a toy would be wonderful with custom midbass and bass horns...

but let me explain the GOTO philosophy on this... they do not care to get the last bit of extension from any horn driver combination... their entire philosophy is to design a horn driver combination for four octaves and use the middle two... the area where the impedance curve and frequency response are extremely linear... they do push the two octave portion slightly toward the flare frequency from the middle, but that is due mostly to their preference for long, slow flares..

following this line of thinking, Ming's horn is actually only about 4 dB down at 60 and approximately flat at 75Hz... this could only happen with the long, slow flare... I bet if we asked GOTO, they would say cross at 90 Hz...

I have spent much time listening to these types of horns as well as thinking hard about the philosophy.... to me, when it comes to home reproduction, this type of thinking leads to not being able to horn load the bass as low as I would like... I would rather have the extra extension and not have to bring a direct radiator into the equation... in the home horn environment, which I truly believe to be superior to all other forms of music reproduction, we must choose carefully to be able to physically place the best setups into our smaller environments... I value time alignment and the goto philosophy allows for bass horns, but not with time alignment... they believe in throwing away that last half octave, at least...

I still would like to say that their drivers, with their extremely strong magnetic assemblies,ultra light and stiff diaphragms, and small exit diameters allow for the potenetial to be the best low mid, and possibly bass drivers currently available... if you would like, I will keep you informed on my horn experiments with these drivers... I have a pair of the 370's (400 to 18k) and 505's (100 to 6k)...

Peace,
Me


Posted by Romy the Cat on 11-25-2007

 Jeffrey Jackson wrote:
Also, I had never dreamed of a driver with a variable compliance resulting in a variable free air resonance... such a toy would be wonderful with custom midbass and bass horns...

It is why I use cone drivers for upperbass, use it as compression drivers - because I have a full control of back chamber and the driver resonance.  People, who do bass horns do not get that the drivers  themselves are as relevent as the driver-horn interfaces…


 Jeffrey Jackson wrote:
but let me explain the GOTO philosophy on this... they do not care to get the last bit of extension from any horn driver combination... their entire philosophy is to design a horn driver combination for four octaves and use the middle two... the area where the impedance curve and frequency response are extremely linear... they do push the two octave portion slightly toward the flare frequency from the middle, but that is due mostly to their preference for long, slow flares..

Yes, I can see it. I certainly disagree in many ways with what they do.

 Jeffrey Jackson wrote:
I have spent much time listening to these types of horns as well as thinking hard about the philosophy.... to me, when it comes to home reproduction, this type of thinking leads to not being able to horn load the bass as low as I would like... I would rather have the extra extension and not have to bring a direct radiator into the equation... in the home horn environment, which I truly believe to be superior to all other forms of music reproduction, we must choose carefully to be able to physically place the best setups into our smaller environments... I value time alignment and the goto philosophy allows for bass horns, but not with time alignment... they believe in throwing away that last half octave, at least...

Yes, I understand it.

 Jeffrey Jackson wrote:
I still would like to say that their drivers, with their extremely strong magnetic assemblies,ultra light and stiff diaphragms, and small exit diameters allow for the potenetial to be the best low mid, and possibly bass drivers currently available... if you would like, I will keep you informed on my horn experiments with these drivers... I have a pair of the 370's (400 to 18k) and 505's (100 to 6k)...
I never had GOTO driver and I never seen anybody rational who use them. Whatever I have seem and heard from Goto users sound to ridicules to me.  There was a guy in Sound Africa, he is OK from my point of view, and he used GOTO lower MF and upper bass if I remember correctly. He told me that he liked his Goto drivers a lot but I never heard his installation and therefore there are no common denominators for any judgment…

The next sing is not related specifically to the Sound Africa guy but my general attitude to the people talk about audio.  You see, people talk about anything and particularly within Internet anybody have point of views and experts assessments. My vote uselessly is not for the people who run mouth but who are able to demonstrate actual results – mean the sound of installation with noble objectives. Unfortunately the noble sonic objectives it is a big rarity and in many instanced people running around stadium are so behind that they begin to feel that they are leaders…

Goto might be good drivers but what would it mean “the best low mid …. drivers currently available”? The best horn divers are the drivers that the more perfectly serve the interests of a given horn. Anyhow, keep updating about your Goto journey. If they have a driver with 70-100Hz resonance I would try one for my upper bass horn but a driver with Fs of 24Hz will not work out for me. BTW, the extremely strong magnetic assembly is might not be… NOT necessarily be a good thing for bass horn loading.  For MF and HF driver it is good but for LF driver it is controversial. My experiments with electromagnetic drivers suggested the for bass drivers I would like to have as less as possible magnetic damping…

The Cat

Posted by Romy the Cat on 12-11-2007

I would like to make a few comments about the entire idea of those expensive Japanese compression drivers: GOTO, ALE and alike. I have voiced the near-similar outlook about the irrational exuberance that some audio people express about electromagnet drivers:

http://www.RomyTheCat.com/Forums/ShowPost.aspx?postID=4716

it was not about the drivers themselves (so far I do not see a credible advantage of electromagnets) but about the idiotic preoccupation of those people with artificial cost of the electromagnetic drivers. Anyhow, my views, mostly critical views, about GOTO’s prices would be from slightly different perspective.

I do not like the GOTO pricing politic. I do not just complain about the fact that they are expensive.  However, I do insist that keeping prices for these drivers extremely high GOTO is  shooting itself (or most exactly the customers) in foot, getting worse Sound from their drivers, getting worse juts because the high price. I will explain why I feel this way.

Please do not take my comments as an typical audio person’ bitching about the price of something that he can’t afford. I am actually stupid enough to afford to pay $20K-$30K for a driver for my speaker. We are, the snob-enthusiasts of horn loudspeakers, the people who spent a lot of time, money and efforts on our horn multi-ways, the people who take horn-loading concept to its implementation extremes – we are the people that companies like GOTO live and die to serve. Do GOTO really try to serve us? Well, it is more complicated, let look deeper…

GOTO is hardly serious speaker manufacturing company. They do have own views, well traditioed views, but their systems, the complete systems are well beyond any sensible criticism. The design concepts that GOTO invests in this “recommended systems” are so bogus that it is truly laughable. I am sure many of people who have interest on the subject did look at the pictures of many GOTO installations with GOTO channels dropped in a random order, with no time alignment, with absurd horizontal offset with axis angling… Erh!!! Looking at the GOTO-sponsored speakers I feel that GOTO is not speaker manufacturing company but rather a company that makes raw compression driver and sell then as OEM or DIY parts. I completely disregard all GOTO horns and their recommendations how their drivers should be used… as I feel they do not know it.

(I need to make a comment here as I do not necessary feel that Mr. Goto and Co is necessary are ignorant but I do know that they have own rational to keep public position and public attitude of the company in the direction that make them comfortable to sell products and services to generally idiotic audiophiles. There are a great number of industry people, and I can name many of them, who are in the very same boat and who sell to public a fraction of own capacity or on many instances intentionally faulty solutions knowing that better solutions will not be appreciated anyway but the customers they have.)

First let look the price of GOTO (ALE) drivers – the $10K-$50K per driver in retail, indeed sound as expensive. Some manufactures, for instance Vladimir Lamm, to make final prices multiply expanses 10 times – they are perfectly in their right to do so. If GOTO sells a driver for $20K-$30K then it means that it cost 2K-3K to make it. My experience to deal with custom drivers indicates that it is about right: if I for my own custom driver that I need then I would cost me ~$4K (and few years to found out what works and what does not). Do not forget that I am taking about a pair of drivers. If I order 200 of those drivers then the cost of each driver goes down to $310. They are actually the real numbers of my 5-poll Quartopuss driver:

http://www.RomyTheCat.com/TreeItem.aspx?PostID=3151

I am sure GOTO do not sell or make a lot of drivers, why? Because they would like to keep price high, however that prevents to expose GOTO drivers for a wide array of OEM or DIY people. Please remember this simple result – GOTO drivers are not being exposed to common practice of horn public.

Anyhow, the untold truth about the speaker drivers that they are very cheap to make and the prices go down each year. The magnets nowadays cost nothing, as well as many other technological parts. What has some cost is the GOTO know-how but that know-how, whatever it worth, has been expensed long time ago. So, GOTO build their drivers with 20-30 times retail mark up with objective to keep the artificial retail price high. Even in Japan, where GOTO prices are a fraction of US retail price, the GOTO drivers are still very expensive.

Keeping retail prices of $10K-$50K per driver GOTO does something negative to themselves – they eliminate a wider community of perspective OEM and DIY customers, the customers who would be able to make USE of the GOTO drivers in their own, more advanced then GOTO’s original applications. Now we enter as very dangers zone. I claim that keeping retail prices of $10K-$50K per driver GOTO explicitly select for themselves very peculiar target of perspective customers – the ignorant and uninformed customers.

I certainly do NOT make a statement that anyone who use GOTO drivers are ignorant and uninformed. Still, I do insist that anyone who USE GOTO ideas “as is” would be an ignorant and uninformed person in the subject of horn systems. I have heard two complete GOTO installations. Whatever good or bad they were the owners of those installations were very unacquainted with horn loudspeakers. The owners were very nice and intelligent people and very fine in what they do (that made them to make enough money to afford GOTO-based systems) but they had completely hands off approach in audio. Somebody came to them, build up GOTO-based systems and showed them where to connect speaker cables. Those people did not use GOTO driver as creative tools of their installations and they would embrace with the very same enthusiasm the results if the speakers TAD, JBL or TOA based system.

So, where I see the problems with GOTO price approach? I see the problem with GOTO inflating the price of their drivers, keeping people with experience and skills how to use compression drivers out of loop of perspective users. I would like to see dozens of horn’s DIYer embrace GOTO drivers and experiencing with them. Let those peoples to be even as moronic as AudioAsylum.com and DiyAudio.com level – it is not a big deal. I would like to see a few horn turners that we have left in US to accommodate their horns for GOTO drivers, and have customers who use it, collecting knowledge base about the results.  I would like to see horn manufactures, starting from Cessaro and ending with Bruce Edgar have options in their speakers to accommodate GOTO drivers. I would like simply to see GOTO driver being used and do not be concentrated in the hands of some freaks to reach whom it is necessary to fly 8 hours. Hey, it would be nice if after the fly you do not witness a moronic setup with GOTO drivers… I porously did not see any photograph or description of a single GOTO installation that I would feel comfortable.

The compressions drivers are superbly important but they are very small fraction of a successfully performing horns installation. Let me to approach from another side. What would I consider be a reasonable price for a good compression driver? I feel it would be around $5K or perhaps $7K of the driver is too obnoxious.  Why so much? Because it will be juts ~3 octaves, because it will need 3-5 other drivers to support itself, would need time and much money invested into horns and horns arrangements, and because it cost $300 to make the damn driver. I can understand the manufactures that use those “serious” drivers to sell acoustic systems for $100K -$150K. I also can understand GOTO that sell 6 drivers for $10K and the systems for $60K. The “system” according to GOTO is just 6 drivers, the drivers crazy-glued together, with ZERO investment in the entire system design. That is why GOTO system are so brainlessly made – because they have no cost invested in “system” but juts bogus inflated cost in the system’s drivers.

Sure, if GOTO willing to continue to sell 8 drivers per year and to serve their explicit club of arrogant but ignorant users then it is fine. If however GOTO has interest to become an Instrument of Sound and do not afraid to compete then I would suggests GOTO to drop retail price approximately 4 times, soliciting wider margin of customers to USE the GOTO drivers. Her is the most important element: devitrifying the exposure of own drivers GOT could make OWN customers to tech GOTO how to use their driver and perhaps GOTO might found ways to make the drivers BETTER than they are now in context of more demanding systems (since GOTO with their OWN system designs are clueless what they do).

Once again, talking about the price of GOTO drivers I defiantly do not talk about profit that manufactures or dealers make – whatever they do it good for them. Here as in many other posts of my site where I try to use price tag of audio equipment as an applied tool that has ability of driving the results. I think that high price of GOTO (ALE, YL and few others) drivers do not serve Better Sonic Results for GOTO. Exotics price is fine but it should come in a package of a complete exotic solution that deliver BETTER exotic result. So far what GOTO offers is a set of expansive exotic drivers imbedded into extremely mediocre system and a set of extremely ill-mannered design view. I do not think that it made many people to pay attention to GOTO. Dose GOTO willing to promote itself as a Rolls-Roys engine sitting atop of Honda Civic chassis?

The compression drivers are juts very rich musical instruments of symphonic orchestra and to be able to yield own capacity those instruments have to be used by qualified musicians. With being played symphonic orchestra instruments become a museum, audio become a literature and the Japanese Stereo Sound Magazine become a pile of audio pornography.

Rgs, Romy the caT

Posted by MINGSU on 12-11-2007

FYI - for all,

The GOTO is a very small company located in Japan that has devoted the whole 3 generations of GOTO family to produce only one product line - the GOTO speaker driver.  The annual production capacity is 240 driver units which mean only 20-25 4 way systems can be produced per year.  The waiting list is always 2- 3 month back log because there is no short cut to mass production of such precision audio transducer.  I wish that we can buy thing just by the raw weight of the material used to build the product but that will be an insult to all the artist around the world - the past and the future.

I do agree that with knowledge and know-how, one might be able to find a way or even a better way to build a horn system to enjoy the music.  That is the fun of this hobby but for people do not have the know-how or time and resource, GOTO do provide alternative path to the horny heaven.

-Ming


Posted by Romy the Cat on 12-11-2007

 MINGSU wrote:
The waiting list is always 2- 3 month back log because there is no short cut to mass production of such precision audio transducer.

Ming, I disagree with this sentiment. Any manufacturing is mass production; the question is only about the level of technological sufficiency of production.  I do not believe that GOTO guys run turning mashies a cut manually each driver. If they do then they juts waste this time and customer money. Drivers have pole pieces, frame, phase plugs, some other things that I am absolutely convinced they outsource to any CNC machine shop that dose it for GOTO as mass production for years. It is a very ordinarily work for any machine shop. The cones, their suspension and assembling of the drivers is more complicated but it also is perfectly rational technological and highly algorithmable steps. There is not “art” or “magic” involved in it and it is not the Nihonto manufacturing process (that is perfectly-technological as well). The “complexity” derives from the fact that in GOTO perhaps very few people within very restricted manufacturing facility do it. Perhaps 1-2 people, in home shop part time. There is nothing wrong with it except the fact that price is a justification of their insufficiency not the absent of “short cut of production”.

Also, do not stress the “precision” of GOTO drivers. GOTO do have high flux and most likely very narrow gaps. So what? It has to do with the precession of specification they give to their machine shop and with the off-axes precession of cone suspension. Still, TADs have 2.4T in gap and they stamp them like mushrooms after a rain.

Please do not feel that saying it I am trying to demonstrate disrespect to GOTO efforts to do their drivers. I just say that in “precision audio transducers” there is nothing that prevents them to be mass produced.  I think you are as a distributor would be the very first who would be benefited if GOTO drivers where more readily available. Then you would not tell to people stories about the “such precision audio transducers” but just let GOTO drivers to compete with this competitors on open market and with the telling legends bout the 2- 3 month back log.  Perhaps it is my corrupted perception but when I go to buy a car and a sales person inform me that if I pay $100.000 more than gas in my car will be not supplied not by a fuel-injector but a manfully measured milligrams of fuel then I ask myself: do I need to move in this car from point a location A to a location B or I need to entertain myself with gas measurements.

BTW, this brings an interning idea for you: why don’t you tell on your web site more about the GOTO drivers, partially about the “precision part” and what from GOTO point of view distinct them from their counterparts. I think it would be beneficial for GOTO for you and for people, who might be interested about the GOTO drivers.

Rgs, Romy the Cat

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