Romy the Cat wrote:

It is 4” exit and reportedly goes down to 27Hz. I do not know what a lot about this diver but it might be a good driver for 40Hz horn. 4” into 40hz? God, it has to be at least 16 feet long horn! I would take my head off to somebody who goes for it.

Romy the Cat wrote:

As I said above your you "experienced today  with GOTO" is just your transitional feeling and you will change this feeling many times. To accommodate a pair of 42Hz horn in a system is a year-long project otherwise you get an accidental result. In a few month loving your horns you will be sick and tired to wok around them in your listening room, or perhabs you will feel that the horn displacements changed acoustic in your room too much, as the result you decided to hide the horn while it sound  and integrated well... good luck with this projects. To drop driver into random horns and to love result is not the same as to get max from a given topology...

Regarding the new design. It is more to my liking, which might not mean anything. I do feel that the upper bass horn is a bit too bulky for your design. If you go for Tratrix then it will be juts 36" long and it would be way more balance. Also, having the midbass horn you have no need to push the last few Hz out of upperbass horn.

I do not like the frame. It has nice air feeling but I think it is too flimsy and good only for sketches. In the real word when you hook your horns and driver you will see that it will become incredibly heavy construction and even if you go with metal bars the thing will swing and lean. If you do inset to have this curved frame then consider on a back an arm with contra-weight that would balance the mass of the horns in front. You also will not able to move the hors up and de in this curved configuration - you might find it useful. If you insist to have this design of frame then add a surface at the bottom of the upperbass horn otherwise you would need 2 people to move it. Also, from the bottom of the frame, approximately from elevation of a tweeter run a single metal bar to the back of the floor circle. that would give you a third leg and will make all of it more pragmatic.

Regarding the proposal to lend me a pair of the GOTO SG-146LD-4 drivers to let me to experiment with them. I would decline. To make a proper horn for 146LD and to accommodate  it would be a project that would take more efforts then I willing to spend nowadays. Even if I own the driver I will let it sit in a box, wanting for time we move to next house.

The idea to make similar driver is not a bad idea - for bass reproduction it is very simple - no phase plug at etc... Everything hits the wall when we are taking about diaphragms. Are you willing to spend next 5 year of your life experimenting with diaphragm making? I do not have it now in me. Perhaps I will do in a future  but it would be in "project management" format and won't be doing everything myself as I use to do. The reality is that with an infant in my hands I do not do critical audio nowadays. Thomas just become to crawl two weeks back and become a bit less needy and it gave me some free room to spend for some more or less critical listening....

Murataltuev wrote:

Here is frequency response without horn: Here is in my 46Hz horn (green is GOTO, blue is Supravox):

Murataltuev wrote:

I did some experiments today again with GOTO in my existing horn and it is obvious for me that I need different horn for GOTO.

Murataltuev wrote:

Existing horn was modelled and designed for Supravox and I see perfect curve with it.But GOTO in it shows same curve for 50-100Hz but then drops significantly till 400Hz and then rises to the same level till 1000Hz. But even with this terrible frequency response I hear sound of another league!I tried to return to Supravox, because I have no idea what horn I need to make for this GOTOs, but can't any more. I want GOTO's transparent, lite and airy bass. Can someone suggest me what kind of horn to make for GOTO?Here in Moscow it is very cheap, so I can try to make different ones.The only problem is that it can't be longer than 2 meters. Please, help!

anthony wrote:

Perhaps that GOTO hole centred on about 225Hz is to do with using the incorrect throat in the horn?  First thing I would do is extend the profile of that big horn so that it reaches the correct throat size for the GOTO units.  It is going to be much longer than 2m long though:  small diameter driver = longer horn...there is no way around it.  You may be able to mitigate this by using a tractrix horn profile because they are shorter than most of the others..

Romy the Cat wrote:

The Supravox was 12” the Goto 4” how did you convert one into another? You would need a 3-4 feet adopter to do so.

Goto has 4” exit – it is what it is and this gives to you the throat of the horn. Then decide what lower frequency you would like to get from it. Let say it will be 40Hz. Calculate let say exponential horn for 4” and 40Hz and you will have your target length. For instance it will be 9 feet.

installation as example: I do have 40Hz horns working nicely with the system and they are not visible or detectable in the room. No HornResp would give you any advice – the system design is the derivative of your mind and your creation.

So, instead of thinking what kind horn you might need to build you need to think about completely different subject: “How will I integrate my horn into my system and my life if I did build it?” You need to have a clear and agreeable with yourself plane and only then build the horn. After a proper horn will be build you would need to spend time with the horn and driver to teach them to sound in the way you expect. It will take time to learn about loading, back chamber (in your case back exit damping), crossovering and many other things.    Rgs, the Cat

Murataltuev wrote:

I can't go longer than 2m. Any suggestions about configuration of horn with this length limit ? May be higher frequency ?

Murataltuev wrote:

HornResp can help to get desirable frequency response and other parameters. But I don't know how to use it for GOTO drivers. I don't think that I can get Thiele-Small parameters for modelling. So, only experiments...

Murataltuev wrote:

I think I missed about your 40Hz horn. I don't see any information or reference at Macondo dedicated web-page (http://goodsoundclub.com/MacondoAcousticSystem.aspx).Can you suggest what thread to read about it ?

Murataltuev wrote:

Longer horn will need another room.

Romy the Cat wrote:

Curve the horn. If you Goto channel will not care any HF over let say 150-200Hz then you might curve the horns, similar to what WE did with 15A.

Actually you might get some TS parameters for Gotos if you find right people to ask. I do not have them but I am sure there is somebody out there who do. The problem is that those parameters are very much irrelevant  and you should not be interested in them.

God, I wonder how many people out there keep saying it!!! That is of course unfortunate truth… BUT the whole idea to be creative is to find a way to incorporate a larger horn then the room can afford.  There was a saying in Russia that Jews do not work harder but smarter. Not that I agree with the saying but it is not a debate about racism but rather an illustration that there is always another way to think the problem. Do not forget that the thread I linked above was followed after this thread:    http://www.goodsoundclub.com/Forums/ShowPost.aspx?PageIndex=1&postID=11190#11190    It is possible that you can go over the walls or do anything “creative”, well then curve the horn or introduce one or two bends. The 90% bending is very complicated subject  and it very much might kill everything, Still it is doable if to approach it with proper direction and proper techniques.

Murataltuev wrote:

Actually you might get some TS parameters for Gotos if you find right people to ask. I do not have them but I am sure there is somebody out there who do. The problem is that those parameters are very much irrelevant  and you should not be interested in them.  Ok. Anyway noway for me to get them.

Murataltuev wrote:

Actually you might get some TS parameters for Gotos if you find right people to ask. I do not have them but I am sure there is somebody out there who do. The problem is that those parameters are very much irrelevant  and you should not be interested in them.  Ok. Anyway noway for me to get them.

anthony wrote:

Have a look at this.

Romy the Cat wrote:

That is my constant dilemma while I socializing with audio people. Om a surface the question about T/S parameters for Goto is reasonable. It means now I need to correlate whoever I know Goto user and the people who know how to measure T/S and then drop a few names. However, I also do know something about sound horns and I know that T/S is absolutely irrelevant for the horns design, particularly with this type of driver. Moreover if the horn is made properly and the driver performs at its best then the T/S parameters of the original driver must be overridden. So, what would be the advise to me: to be a nice guy and to patronize the irrelevant question that only lead the people astray or just  to discard the question?  Again, trash the HornResp, forget the T/S parameters and start to build sound instead of  practice near-audio community amusement. I have ban (did not support) any conversation about HornResp at my site long time ago. If you would like waste your time with this then there are plenty of other sites to do so.