serenechaos wrote:

-Background- Enspired by Jeffery Jacksons system as displayed @ VSAC, I'm building a five-way horn system.

How are you planning to power the thing? The amplification pattern will affect the selection of your channels.

serenechaos wrote:

65Hz Tractrix from ~80Hz to ~400Hz w/ fane 8";

It will not work. Fine 8” is a good driver with 86dB air resonance and it might be good for 100Hz horn minimum. In 65Hz horn the 8" Fane will be underperforming.

serenechaos wrote:

250Hz LeCleach from ~400Hz to ~2kHz; Oblate Spheroid to match 2kHz crossover point, to 10kHz;

Might I ask why you desired to  use two channels in this range with 2K of split? You will pay with some near filed restriction in this configuration.

serenechaos wrote:

I have a pair of Radian 850PBs and 475PBs to use at first, but would like to build compression drivers matched to the 400 - 2K and 2K - 10K frequency ranges.

And what specific moments you do not find satisfactory with you Radians that it inspired you to build your own drivers? I might have some leads for the rest of you questions but it would be interesting to hear what your sonic strategic objectives are.

serenechaos wrote:

At first I plan to power the thing SET, with a known, existing amp (a  triode wired EL84) which I've already built and know the Sound.  It is not bad, but a little "warm" sounding (second harmonics, and is low powered for low frequencies.  Then I use a 304TL amp, (under construction, another known, a much cleaner sound, ~ 5 wpc).  After I get the horns built, and working, (play with crossover points, etc) build dedicated SETs for each channel.  I don't want to attack too many variables at once.

The reason I asked about amplification is because the type of amplification you use has a relation to the type of the magnets the amp might with comfortably.  Also, the amount of the amps would inform if you have opportunity to manage harmonics and transients for each channel independently. So, it will be a single-ended triode amp and in future possible DSET, right?

serenechaos wrote:

Since this thread is for compression drivers, I didn't go into detail on horns; but horns and amps information is necessary to talk about compression drivers...   I also discussed it with John Hasquin in depth several times.  We not only discussed horn making, but he also approved the idea, and added ideas to change if it didn't work out at first.  It may not work, but I'm going to try it.  If the fane doesn't have enough umph, I'll use something else, or make a driver that does.

Well, if you talk with John Hasquin about horns then you do not need to talk about horn with me. John has was more superior intellect about horns then I do and you are in good hands with John.

serenechaos wrote:

The whole idea is to keep all the horns and drivers in about a 2 1/2 octave spread.  To keep everything in the middle of its most "comfortable" "resonate" operating frequency.   Not to force anything too high or too low.  The mid-hi and mid-low expansion rates and cut-offs are also designed to match directivity at the crossover point.  (60 degrees @ 2kHz).  Again verified by both the above.

OK, but you need to understand that you will pay the “minimum proximity” penalty for this. According to the Macondo's Axioms you will need to position channels vertically.  And if so then you will have 3 relatively high frequency firing channels that would take ~3 foot of height. If you do not care about near-field then it is fine but if you do then be advise that the idea of mid-hi and mid-low channels might set the minimum  distance where the drivers are integrated for 1-2 feet back.

serenechaos wrote:

Integration between all channels is one of the main things I'm trying to achieve.  I keep thinking of the Oswalds Mills installation @ RMAF.  It sounded like three very nice drivers, not one coherent speaker system.  I want everything to have the same "voice."

Well, the Oswalds Mill installation is not something that that I consider worth any attrition. My attitude to the guy who run the Mill is well know – he is an idiot, anything he touches is idiotic and anything he does has a huge stamp of idiocy on it. If playbacks are reflections of our objective in sound reproduction then the Oswalds Mill’s systems, ideas and steps are the pure reflection of that Jonathan Weiss’ idiocy. The showy, empty and scared peace of fucking nothingness and his audio does reflect it. There is nothing further that can be said about it.

Anyhow, I still kind of did not hear from you what are you trying to do, not how but rather what. It is not that you need to share but my mine in audio work in different way (http://www.romythecat.com/Forums/ShowPost.aspx?PostID=432). Whatever you put together and connect to amps will sound. The question is what kind sound are you looking for?

I see, I misunderstood you, Robert. I was under impression that you “speak horns” and that you have lived with variety of horn-loaded playbacks and ideas and now you have decided to go for making your own compression drivers. If you did not and it would be your first multi-wave installation then I would encourage you to put the idea of own compression driver in back burner for a while. You see, a sound of compression driver might be assessed only in context of own charnel and only in context of everything else. It would be defect for me or anybody else to pitch you ideas what to try with compression drivers until you have you own ways to sonically evaluate the validity of those proposals. So, if I were you then I would build your multi-wave system, use any  conventional drives you have and then, after you get the reference points of what you are getting I would  consider what  specifically I would like to address/improve  by the introduction of my custom-made compression driver.

BTW, if you pick brain with Jeffery Jackson then, considering what he posted at this site, he sounds like a lucid person to ask for horn advisces (I can’t believe advice has no plural!!!). Between, John and Jeffery you would hardy need anybody else.

Robert, what I meant is following: when you will be collecting requirements for you own drivers specification and will evaluate the implementation methods then you need to have you own identity what you are trying to do. I might post a lot of different thoughts about what might work interestingly in compression drivers. I am sure others would do the same but it will be not definitive direction but rather an array for exploration. No one can defiantly and predictable say hop the driver will sound and in particularly no one can say how it will be sound loaded into a horn. So, when you hear people talk about requirement to the drivers you need to have a lot of YOUR attitude to discriminate information and to accept only what makes send to you. Otherwise you will get conversed into junky aka your Oswalds Mill’s guy of the Brazilian retard Angeloitacare who jangler the empty phase with no understanding of the phase’s meaning.

If I were in your shoe I would take make as you wish but wish a slight correction:

65Hz Tractrix from ~80Hz to ~800Hz w/ fane 8" ( or better driver)
250Hz LeCleach from ~800Hz to ~10kHz
JBL 2405 ribbon from 10kHz up

As you see I leave away the sub 800Hz horn and combined two MF horn into one. The bass horn is a pain in ass.  It is a good idea to see if your wife will tolerate 80Hz horn before you go for something larger. Ask, Jessie – he will read you a lecture about it… Also, MF horns only is already something that would allow you to play with playback and to make own conclusions.  Also, I combined for now two MF drivers into one – it is simpler, smaller and you always will be able to convert the universal MF channel into lower MF channel and then add one more supplementary upper MF channel. You need to pick a good and neutral MF driver; I always propose the JBL 375/2440 or the similar and make the given system to sound right. Then, only then, after you identify what in your view the system weakness, you will be in position to evaluate your own requirement and to how you would develop you playback further. At least it is how I see the things…

serenechaos wrote:

I'm just looking for any good information on how really good drivers are built; and where to look for if there are problems.  As you have evaluated quite a few drivers I thought you (or someone else) might have some suggestions.  I ask everyone I talk to, read everything I can.  File what makes sense, discard what doesn't.

Ok, when I have time and  be in mood I will try to compile some thoughts about custom MF drivers (are we talking about MF drivers, right?). BTW, you might get in touch with Richard – one of the guys of Cogent group. Richard is as well as you are a modeling-machinist and he built the Cogent drivers. I am sure you will find a lot of common grounds to discuss.

serenechaos wrote:

When we were @ VSAC, my wife and I sat down in the room Jeffery's system was playing in.  After about a minute and a half, she quietly turned to me and said "you can build one of those, right?" with this hopeful look in her eyes.

What a stimulation! Where do you found women like this? Or perhaps your wife just a smart woman who knows how to live being a women – in either case congratulations and accept my envy.

Wojtek,
Yes, too late.  Once you've heard a good "stupid horn installation", there's no going back is there? 

Yes, something similar to what was shown in Jeffery's GOTO installation. It should work the same on the floor or ceiling, (loading wise) as long as the mid-bass coming from above doesn't sound strange.  I'll build them so I can mount them either way, and try them both ways just in case... 
Why? Long story, but here's a quick, dis-jointed explanation which boils down to less ripple, less distortion. 
The horn was designed around the 80Hz crossover point on Jeffery's suggestion, and everything else around that.  I tried Tractrix, Expo & Hypex.  When you truncate they're close anyway, but John said the same thing about expansion profile and distortion.  Expo & Hypex give a little more bass extension, tractrix has smoother frequency response, less ripples.  It's taken me months to get this far, and this is the best yet.  It's flat + / - 1 1/2 dB from 80 - 400 Hz, with a slow roll-off after that.  The mid-bass was the hardest piece to get to work right on paper, and will probably be the hardest to actually build.
I know many people say not to use tractrix for mid-bass, that you can't annul the reactance with the compression chamber volume, but I'm banking on that not being true. 
That's not what the math says, or what people say who've actually done it.  That's who I believe. 
Like I said before, Jeffery's system sounded so much better than anything else I've ever heard, that I do listen to whatever he says as comming from someone who's been there, done that.  
 
Romy,
No rush at all on my side!  I'm just trying to gather resources. 
MF-- Anything you care to share thoughts on. 
Mid-bass, low-mid, or high-mid especially. 
I doubt I'd mess with the sub or tweeter--I haven't built the sub yet, I'm told THs of this type work fine as is, and I have been using the JBL 2405 and can't fault it if crossed high. 

Congratulations accepted, however I must add I feel very lucky, and realize I had nothing to do with it.  I think the "perhaps just a smart woman who knows how to live being a women" is what's going on.  That and she loves music. 
Robert

Romy, 
Somewhat on topic, but it could go many different places--
My wife told me that I really should thank you for posting things like:
http://www.goodsoundclub.com/GetPost.aspx?PostID=3184&Phrase=kharma 
that help people like her know what to listen for, even if it it BAD Sound, and why. 
Not many places one can get educational information like this, and it is very helpful. 
So, Thank You from Deb.
Robert

Romy the Cat wrote:

OK, but you need to understand that you will pay the “minimum proximity” penalty for this. According to the Macondo's Axioms you will need to position channels vertically.  And if so then you will have 3 relatively high frequency firing channels that would take ~3 foot of height. If you do not care about near-field then it is fine but if you do then be advise that the idea of mid-hi and mid-low channels might set the minimum  distance where the drivers are integrated for 1-2 feet back.  serenechaos wrote: Integration between all channels is one of the main things I'm trying to achieve.  I keep thinking of the Oswalds Mills installation @ RMAF.  It sounded like three very nice drivers, not one coherent speaker system.  I want everything to have the same "voice."  The Cat

serenechaos wrote:

How were the Macondo's Axioms arrived at? By listening?

serenechaos wrote:

I am wondering why/what happens if channels are not positioned vertically.  What does it do to the Sound?

It relates to lateral resolution of human hearing. We have very high lateral resolution and very low vertical resolution, I do not remember exact numbers in time of angle by frequency but you might recognize it without numbers. Take a look at the configuration of human head - ears are located on right and left side creating base for horizontal space localization. The space localization is a delta between arrival time to right and left ear, so if the sound source is somewhere within horizontal plane then the aviving delta works. However, if the source is in vertical plane then the location of our ears not optimal to create a sufficient distance between the vertical receptors.  To have the same vertical resolution as we have horizontal resolution we would need to have one ear at chin and another atop of our head. BTW, if you observe the lives of the most sophisticated God’s creatures – Cats then you would see that Cats use “altered” space localization. When a Cheetah sits atop of a hill, observing her territory and see a pray then she try to estimate a distance to the play. Her ears are located atop of her head and very close – there is very little lateral bias and her vertical resolution is even smaller then humans. So, what the Pussy does – she tilt her head in side in order temporarily to increase vertical bias between her ears and to assess vertical distance (remember, she is atop of a hill) very precisely. Sometime dogs do it but they do it not because they are smart but because they try to imitate Cats.

serenechaos wrote:

You spoke above about the "minimum proximity" penalty.  Does this affect only how far back the minimum distance for driver integration?  Or other things as well?

I do not think that if the drivers are match properly (according to their TTH characteristics) then it might affect others things. You also have top take under consideration though is that your MF drivers will be shooting behind the mouth of the upperbass horn and that MF driver will have much smaller horns. The whole idea shell be viewed from a perspective of vignetteing.

serenechaos wrote:

I started thinking about all this due to Bert Doppenberg's Swing I heard @ RMAF.  He said some people prefer it to always be vertical, but he prefers it with the mid and high (co-axial horn to the outside, and the bass to the inside, because there is a wider  image tht way, and there is too much bass if the bass horns are too close to the wall in a small room.

serenechaos wrote:

I wasn't trying to critique Bert, or even get into an in-depth critique on the Swing….  Maybe that's why you went into more description of Bert, and his business?  You feel it is somehow reflected in the speakers Sound?

serenechaos wrote:

I will go so far as to say that I liked the Sound of Swing better than any other speaker at RMAF.  The problems I had with it (Sound wise)-- I am trying not to repeat what made these things happen.  I don't know if it was the "angled, and coaxial" BMS drivers, the BMS drivers themselves, the diaphrams, or the source or amps.  My wife kept saying she would like to hear those speakers with vinyl and good tube amps.  And that's just talking about the mid-range.  How can I say it?  I liked it better than over a hundred other things I listened to that day, but all the colors were mixed with dark brown...

serenechaos wrote:

Bret said the BMS …his web site says he modifies them. I didn't know it then, or know to ask what he did to modify them.  I guess they were even worse?

It is lie, he does nothing to BMS driver to address what is important. When you be working with you own driver trying to get specific sound out of it you will understand what I mean. Bret treats his subscribers with fairytale about the driver’s modifications but whatever he does with them is irrelevant. He knows that BMS is pathetic crap but they are the only drivers that commercially available be for him to obtain. So, he uses what he can and mask out realty with BS literature about “extrasensory charging the diaphragms” – thank for him his customers are mostly Morons and can’t not recognize difference anyhow.

Interning that he and I had this conversation a few years ago at his site (all deleted now). I was challenging him that he might do nothing important with BMS that might improve sound. Knowing, something about the BMS drivers, knowing their design and using a few of them (few years before Bret embraced them) I was proposing Bret not to divulge what he supposedly modify (it would be OK to keep it as his proprietary know-how) but to name one-two specific sonic flaw of the default BMS drivers that his driver’s modifications have addressed. His response was very predictable – he banned be from his forum. I did not sleep for two month after this and maxed out my anti-depressant prescription…

Unfortunately it is very emblematic for all those people and therefore I have very limited expectations when I talk about Sound with the people who practice audio professionally.

http://www.romythecat.com/Forums/ShowPost.aspx?PostID=930

It is like going to a whorehouse and looking for love…

CO wrote:

I have tried a BMS driver a while ago and it was really bad. About a year ago i heard Berts setup at his house and it did not impress me... It was also with the coaxial BMS. Not much depth or resolution. Did have alot of power though but was difficult to determine because of his poorly integrated multi-multi driver subwoofer at the wrong side of the room.. His demo room is not arranged to get the best out of his system.

Well, depth or resolution is the least of the BMS driver’s problems, not to mention the “depth” not strictly drives characteristics. The damn BMS are absolutely atonal, juts miserably-gray drivers and there is absolutely nothing that can be done to them. The people, who use BMS driver in DB design speakers juts do not know better, do not understand it and have general challenge to distinguish results. A few years ago when I asked that Bert guy about his “modifications” I was very least concern about his speaker or about his company or about the idiots she surround himself. For year I have my quest for capacity of compression drivers in the Absolute Tone domain and I know that it is fantastically difficulty, close to impossible to make any worthy impact in general tonal aptitude of made driver. Unfortunately Bert took my interest in his “alleged modification” like any other audio idiot would do – with fear and in full battleship gear. So, as the result he was dispatched by me his to the very same direction as many people were dispatched – to screw himself. Thos pure people are so afraid for themselves and for this little spot under sun that they have lost any ability to understand what is going on and what the subject of attention is. The sad and the true story of all this that the stupid idea of use the BMS dual concentric compression, as well as the whole design of Swing is not Bert idea but was given (sold, licensed or whatever) to him a few years back by a guy name Gerner Christensen. Gerner made his sad DIY home speaker with BMS drivers and Bert market them as BD Design commercial product. I might say very high level of confidence that Bert hated everything that Swing with BMS does but it is business – who gives a damn what a product does if there are Morons who pay for it. He also has a “help”. The Gerner (what I read by him indicate that he is absolute idiot) made his duty to cruse internet, found anybody why say anything negative about Swing and to slam the people with Sara Palin’s intelligence. People, just do not know all of those things, and trust me I so not say even a fraction of what I know and what I might say on the subject.

Why I do not? Because to the simpleton’s surprise to attack BD Design is very much not my intention. I have absolutely no interest in BD Design, Berts, Gerners and all “politics” that they surround themselves, not more that I have interest in any other company. My interest in the subject purely sonic and all those industry of semi- industry freaks juts cannot understand or afford it. You want more thoughts about Sound and less conversations about audio cretins who protect own ego instead of serving interest of Sound?  Well, buy the BMS driver and build a speaker around them, any speaker. They you would have your own judgment and would understand why the BD Design’s clan had raised their funny-violent defiance against my “interest” in their speakers. BTW, there are a lot of more problems with Swing then juts use of BMS but there is really no audiences to understand it as the “human factor” in this subject is the subject in my view.

In the end I would like do not continue BD Design topic in this thread. I truly see no BD Design’s swing as not something that “pushy” in term of critical performance and I do not feel that people who group around BD Design are qualified to talk about Sound, at least with me. If somebody might report a successful use of BMS then it might be worth to share but please let the pure BD Design crap to go, at least leave it outside of attention for this site. The chewing upon sonic mediocrity and fear of exposure is not what I hope this sithe is all about, at least it is how I would like it to see.

Ok that was a long road to "stick with vertical alignment, and stay away from BMS." 

Back to compression drivers, and implementation... 

If I were in your shoe I would take make as you wish but wish a slight correction:

65Hz Tractrix from ~80Hz to ~800Hz w/ fane 8" ( or better driver)
250Hz LeCleach from ~800Hz to ~10kHz
JBL 2405 ribbon from 10kHz up 

How did / do you go about choosing crossover points, other than by listening and experimenting? 
(e.g. the 800Hz point). 

I'm trying to wrap my head around the above suggestion--
It seems simpler on one hand, to eliminate one driver and horn and crossover at first,
then just add them in later. 
On the other hand, it seems like it would take more to "voice" the system with having to chase crossover points twice.   
Horns just seem by nature to work better narrow band-width, and good sound would seem easier to come by with not forcing the horn to sing out of it's range. 
Thanks,
Robert