From the perspective of pumping of atmospheric pressure the ALE bass drivers might be more capable transducers. It or might not be so as well. To get 40Hz at 110dB in 5” it would take some excursion.  I am sorry but you can’t bend the law of physics. Pressure is excursion by surface. In horn we as the horns EQ. Let presume that a horn would add even 10dB then we still have a lot of excursion necessary. The ALE drivers have titanium with plastic suspension diaphragms. The plastic suspension diaphragms are horrible for excursion, they good only for bending. So, I presume that ALE made a very large FRP skirt to let the metal cone to have lower own resonance and some freedom to move. To do it all within 2.3T guy I am sure was tricky. I would pay money to see HOW the P160 is made. What I know about the compression drivers idea I would guess that  a compression driver with too much flux and light soft cone would not make since as it would requires  very precise, almost surgical compensation of back chamber. Since ALE does not have the adjustable damping for the driver then the result is not optimum. Still, I might pres that ALE knows something that I do not know, so I will give to them a benefit of doubt.


Here you can see three examples of suspensions I believe could be similar to ale drivers , as  ale and goto were yosimura labs employees 
before creating own companies to manufacture drivers.  In fact ale line of drivers were similar in design as YL while yosimuras designs came from rca designs.

You can see suspensions diameter gets wider as frecuencies go down. YL 55000 is supossed to go 150 hz, yl 75000 to 70 hz and YL 1250  to 16 hz.
55000 and 75000 are the same magnet structure with diferent diameter to the voice coil. 1250 is bigger and wider and  lots of  suspension.

Note that 55000 unit charges horn through the throat as contemporary drivers usually do unlike the other two that charges much like rca drivers , goto and ale.
55000 unit is a model marketed and designed suposedly by Mr. Kondo who owned YL for a while.I guess he credited the "contemporary" way of horn charging trough internal throat, or may be it was economical choice. 


YL kondo  55000 150hz





YL 75000  70hz? same magnet







YL 1250  16hz? bigger magnet






I,ve been using 55000 unit with 200 hz tractrix horn (500/700hz to 1k/2K) and never went  back to jbl 2482 or altec 290 on that horn.


I believe 1250 unit is like 4 inches throat and looks like ale should be.Cone material should not be equal. Looks like capable of excursion well above we are acustommed to.
May be 3/5 mm?   



Regards


Eduardo

 

 

YL 75000 has heavy phase plug indeed ,  rca style (see sketch) while 1250 ( I never had one) gets a fixed metal dome equivalent  to spherical piece on 75000 and rca  plugs without conical shape pointing the exit of throat. Ironically the 1250 looks like simpler than rca style as cone is the same as every
driver we know, but throat on the oposite side like rca .




I made graphical work on this as i owned 55000 and 75000 then figured out how it could be designed. ALE P1260 looks like a big 75000 (phase plug included) .
May be Ale p160 works like  yl 1250 i suspect. P 1260 (3inch throat) crossed 80 hz while P160 (5inch Throat) goes down to horn low end.
On the other hand yl 1250 is 3inch throat(not 4inch as I said the post before)and ¡¡16 hz¡¡that is hard to believe (see the response graph)
Note the rear duct open but controlled by the cotton fiber(could be regulated)






About voice coil height I would say it gets deeper as driver grows in low end response.increasing from 5/7mm (55000) to 10/12mm (75000) reaching may be 20/25 if you look at previous phographs carefully, for YL1250. It makes a lot of sense. I always thougth that the few big drivers would work fine in midbass horn(say 80 hz).


My thoughts about low frequency drivers and how to do with it, is complicated question but i would relate things as the keys in order of influence:

1.-the suspension : diameter and length of it (excursion capability)
2-the cone diameter (response capability , efficiency at low freqs)
3-The throat diameter grows( to very low frecuencies a must be) 
4-the phase plug or abscence of it (can be only when very big diameter, but then pressure requires limitation of real throat.....so dome without conical shape is enough like yl1250,ale p160 but air exit must be reduced anyhow) as imposibility of say 15 inch driver with very light cone leads to direct radiator working as a driver(No phase plug or air exit reduction).

The driver vs direct radiator dilemma efinetly Is a matter of scale , materials , geometry.manufacturing. Always better a driver unit than direct radiator.......to the point it cant be done by "construction and materials limits" The question is to reach the limit. Seems to me that japanese guys went ahead everybody else on this , so ......let´s see.




 I will try soon the 75000 unit on 90 hz horn, but I dont trust much to be succesful.I belive that the bigger drivers (said to be 16/20Hz or whatever) will do fine at upper bass but not  the lowest end(not to mention the big horn "problem". 
There is some 1250like driver by Ale manufactured  time ago that could be an option as well. 


Eduardo, do you use or do you have listening experiences with YL1250 or with other compression bass divers?  If you can differentiate between bass tone and bass pressure then what is you feeling about the tonal capacity of compression bass divers?

As I said i never had one, so about low freq driver tone only can talk about Yl 55000 and 75000 on 200hz horn  and have to say that even
that horn alone , 6db say 500-2k, is tonally full, you can nearly forget rest of the channels.it pours low frequencies very very well but it is not bass, its upper bass, at best.
what I can feel ,though: this kind of drivers are capable of go down much more than what i have heard myself in 200 hz horn,for sure.That´s why i dont quit and will try
on 90 hz horn.I think it will work even lower than that and would be fine..... then how much lower? my thougts are that if it works to 90 80 60 hz it would be fantastic.


Regards

Eduardo,

Thanks for your thoughts and illustrations. I also do not feel that loosely-suspended very small metal cone might be a right solution for midbass. To develop LF you need pressure, pressure is surface by exertion – there is nothing else. I do feel at that at some point in bass it is more effective to increase size then exertion. In addition the increasing size and using right materials allows a cone to “write” harmonics in break-up mode. I do not know how metal cone of bass compression drover would behave in “collapsing” mode. It is soft suspended –it is very difficult to say what would happen with it. If you ask me that the wide and soft suspension of the drivers like YL1250 might act at LF as secondary diaphragm. What driver cares let say 30Hzn then the driver creates absolutely crazy pressure in the little front chamber. The spherical cone of the excurted cone let presume can handle the press pressure how about the very wide skirt of the soft plastic spider around the cone? This surface cannot handle high pressure and it will be deformed back, contra-balancing the excursion of the voice coil driven cone. It might act as some kind of self-damping but I feel that it take something off from sound as well.

With all my mixed interest and skepticism to the light-coned compression drivers handle any sub 80Hz region I have to admit that I never heard the results. The speculations are great but it might be fun to hear ALE-160 driver working.  As you understand the entry tickets for such an experiment is not just the cost of the 4” bass compression driver – that would be an easy part, but rather a sequel of very costly and very time consuming actions to make such drivers to work properly in context of the whole installation.  Topologically the use of the ALE-160 vs. the use for instance my 15-incher would require very different ways to implement LF, so the mistakes are VERY costly, and the cost is so high that the price of the driver might be negligible.

It is important however to keep sanity and to understand the abstract meaning of the “mistakes”.  They are not truly mistakes but rather purely subjects of Kafkarian fiction. If you built your installation with a pair of ALE-160 driver and 40Hz horns but I built my installation with my 15-incher and 40Hz horns then how to correlate the results? My current installation use some tricks that make any bass to sound very good (5+1 walls pattern) another room might not have it and who the hell know how to correlate the conic results of two different bass channels? So, what we might call as “mistakes” are not truly mistakes but rather “the ways what it is”. Many year back John Hasquin pitched to me a very sane idea. He told me that people who do bass horns do not make it better or worth, they construct whatever they construct, get a random result and then they live with it, calling the results with deferent adjectives. There is a lot of truth in it. Still, I would like to analyze patterns and conditions before committing my own mistakes. Russian says that mistakes are good and that people learn by mistakes. Well, I would prefer to learn by mistakes of others… If I do my proper midbass horn then it will be once in life-span project and I would like to have at least an intellectual pleasure that I knew that I was doing.

Anyhow, I wish more data about the bass compression drivers were available. I with the people who use them were more outspoken. I wish the people who sell/make them did not act so cowardly as they do, and I wish they furnish opportunely for their LF bass solutions to compete on the market of “open availability”.

jessie.dazzle wrote:

Though I have tried to improve my odds through research, and though I am integrating variables where practicable (variable volume rear chambers, horns independent of room structure and therefore mobile), in the end, I'll be largely stuck with whatever I get.

jessie.dazzle wrote:

I'm not entirely satisfied that this single 40Hz horn was properly loading the room, which has a cubic volume not far from what I would consider ideal for such a system …. However, the horn was sitting in the center of the room, not coupled with 3 walls as intended…

Jessie, a single might be assessed only in context of a single horn loading the room.  The rules of the game with the whole system are different. It is not only about the fact that the whole system has second horn. The people who did not play with setting up the Macondo like installations do not underrated what kind expressive capacity Macondo topology offers. People buy Wilson for instance, put it in right location as here OK sound, but this sound has no reference to room. Then they walk and tell to each other stories about fat sound or thin sound…

With Macondo approach it does not work this way as there is no default “right” output from the channel. Since the channels are co-axed and time-aligned, used drivers that do not need any correction in crossovers then the output of the drivers is very much open to the need of a given room. The most important is that the channels are mixable and listing how the room responses it possible to write up absolutely any about of sonic weigh at any sonic region you wish, and you do it with ZIRO negative consequences.

You might combine the out of midbass and upperbass and make them to work together an octave or a half. You might make the fundamentals channel to care the MF lower knee if you wish. You can moderate sound in respect to how your room actually responses and if you have very well defined objectives how you what it to sound then you can literally to conduct the channels and make them to sound in the way you feel they shall be.  I do not even mention what capacity the DSETs offer with Macondo …

So, wait until you set all the system up – I am sure you will be able to compensate with channels mixing what you feel is not “loaded enough” now. There is also a subject of “masking of room gaps” that I did not even touch….

Yes, Ric, thanks for posting it. I have seen it a few years back, in fact I was searching for the images but was not able to find it.  I think that fellow was ether Japanese or from Sound West Asia, I do remember already. It looks like it is 20-30 feet horn it means that he went for 30Hz or sub 30Hz. I would not go so far – 40Hz -45Hz would be plenty for me. It is very interesting how this Asian guy addressed the delay parole on his 25 foot feet horns. Still, the endeavor very much deserves applauds.

I kind of all set with the conceptual ideas how much future midbass horn might be implemented. When I found a house that I like I will be looking how to implement many of the things I have in my mind to the specifics of the given building.

To me the only truly open question to what I have no answer is what driver would be the most beneficial to try. There are 3 types of the drivers that I can see, and they present 2 type of topology.

1)   ALE P160. $23K pair, small throat, compression
2)   GOTO SG146LD4 $40K pair, small throat, compression
3)   My gloriously-toned 15-incher, large throat, none-compression

The ALE/GOTO prices are high. Well, they are the list prices not the “street prices” and I am sure that there are options to pay less for them. Still, price is not what bothers me but rather the complete unfamiliarity with the final result.  If I get the SG146LD4 than to evaluate objectively what it would truly do at 40Hz it might cost over $15K and six month of construction. So, the drivers are not available for try and the even if they are the evaluation of them bens VERY costly and efforts demanding. To buy the driver based upon reputation is also not very encouraging as I did hear any comments from ALE/GOTO that pick my interest, in fact quite opposite:  the more they talk about ALE/GOTO then more conflict and contradictions I hear in their comments. I do not discard the ALE/GOTO options, I just do not know if it worth it.

My 15-incher approach is way more flexible and I know that the driver is able to show off. However, I will not able to as small throat with it. Well, I might but I think it will make it to sound not as good as it would with large throat

Options, options, let see where I will lend…

Romy the Cat wrote:

I kind of all set with the conceptual ideas how much future midbass horn might be implemented.

I would like to expend a bit about my conceptual ideas, as the folks who advised me in this threaded my find my ideas interesting.

In addition to all that I described above last two weeks, after seeing some houses, I am considering also a smaller room of 600-700 sq feet with two symmetrical windows on the opposite walls. In this case I will be able to use the windows as the entries for the horns in more or less time-aligned position.

The images I presented are out of scale and are juts for sake of illustration of concept. With the horn are positioned in headphones configuration it will be problem with underdeveloped bass as a listeners will be in a mouth of the horn and the wave will be too premature. I have writhen about it before in this thread.  So, how to keep the arriving time reasonable but to make the wave mature on arrival?  Welcome to the idea of the Maturation Shields ™

Pretend that 2-3 feet from the mouth of the horn there is a vertical wall of ½-1.0 of mouth size. It might be sand-fill wooden board on 2-3 thick. It serves multiple purposes:

1)      Mature the LF wave  coming from the horn mouth
2)      Defuse the LF
3)      Masking out the minor  time misalignment by randomizing phases and leased edge of the wave 
4)      Shaping the low-pass filter

There is another purpose that is very exciting. Since the horn are installed “finita la commedia” with room correlation at LF, particularly in small room unless you build 7 feet gall resonators. However, my Maturation Shields have ability to be rotated for let say 25 degree. This allow to slightly re- route the pressure flow from the horn and to write at the listening position the pressurizing pattern that I might wish.

jessie.dazzle wrote:

Here's my latest hallucination : So I'm sitting there listening and sucking down a beer, when, à propos de rien, it comes to me; more on how to neutralize a suspended floor. After shoring it up with screw jacks (which btw, would make excellent scratching posts), you simply build up a little damm at each entry to the room, and then... Dump and spread about 4 inches of sand on the floor! I'm dead serious. Apart from the quality it would impart to the sound of the room, it would make for a really cool environment. Not only could you sink your toes, you could sink all cables. Koshka would love it! The pattern that would be the natural result of walking around, would act as a very effective diffuser. Cleanup would be easy; just grab a big rake and smooth things out now and then! Get an elevated brush mat for the entry so as to not track sand around the rest of the house. http://www.conranusa.com/productdetails.aspx?pid=310&cid=Gardeners&language=en-US You'd of course also want to glide arond in a pair of huaraches or baboosh slippers! jd*

I wonder, if to embrace the idea that I described in the Maturation Shields article (a few posts above) then how those external horns might be constricted?

They need to be solid and not to be afraid of sun/rain/snow. They need to be acoustically tough.  Still they I do not think need to be brick-made-level fundamental masonry construction and need to be relatively easy removable if I would like to.  Not to mention that I would like do not hire 30 people to built them and convert it into a “federal” projects.

What I think is following, and places advice me of you have an experience with it or some ideas.

1) Calculate the horn geometry, parabolic profile and if necessary curves using the windows size as mouth
2) Remove the windows
3) Attach to windows whole 4-8 metal bars of 12-14 feet that are custom-made in accordance to the horn internal profiles
4) Wrap wire around the bars, sweating a inner-skeleton of the horn
5) Continue wrapping wire around the bars, interlaying it with sheets of paper/cardboard
6) Pure (poor, purr -how the hell to spell it!) cement or concrete over the wire/cardboard, making the horn.
7) Repeat the cement application for a few times until will be as I would like it to be.

I see it a relatively simple and cheap project, a weekend or two long. Do I know what I am talking about or I just BS myself?