Member Linear started an interesting thread "Horn / Waveguide Contour Comparisons" which you can find here:
http://audioheritage.org/vbulletin/s...824#post130824
There came up the question for the "Kugelwellentrichter" (spherical horn) developed by KLANGFILM around 1950. The following articel gives a detailed description.
____________
Peter
Here are some more infos by pics. Btw. KLANGFILM always made square cross sectional areas.
____________
Peter
really very vintage stuff
I saw some fans r using it.
A government big enough to give you everything you want is big enought to take away everything from you
A government big enough to give you everything you want is big enought to take away everything from you
this is what u want
A government big enough to give you everything you want is big enought to take away everything from you
A government big enough to give you everything you want is big enought to take away everything from you
A government big enough to give you everything you want is big enought to take away everything from you
Siemens 36 cm Smf.Lsp2a full range driver
A government big enough to give you everything you want is big enought to take away everything from you
Runs with StarOffice or Open Office. Enjoy.
Download below.
___________
Peter
EUROPEAN PATENT OFFICE
Searched here for number 279947:
http://ep.espacenet.com/numberSearch?locale=en_EP
(Patent is in German)
____________
Peter
http://www.diyaudio.com/forums/showt...pagenumber=141
The above thread over on diyaudio.com is a huge canvas of all the issues around building a hi sensitivity system using large woofers and horns.
Certain well regarded members of the audio industry have also left some interesting post around the JBL K2.
I usually take all this type of stuff with a grain of salt but when the K2 and the Westies both get slammed by Charles Hanson of Ayre fame I take some notice.
This aspect of the discussion is around how far you can take up a woofer before audible problems ocurr.
This interests me because I am iconsidering a high senitivity two way system using the 2435 be driver, a horn of some sort and some sort of woofer. Lots of choices.
Of course it depends on your expectations of a diy project as to what is acceptable and what you think are the key important qualities. ie dynamics, timbre, imaging, low distortion.
Sadly the more sensitive systems seem to excel in the former and the latter. To get all four qualities seems both complex and expensive or is it?
Then there are the die hard opponents of CD and non flat power response horns and the guys who insist on coaxials and helper woofers and OB's.
Earl Geddes has recently published a kit what he claims has been optimised for all of the above qualities. The devil is in the details and Earl claims the results have little to do with hype or subjectivism of the designer but sheer science.
One interesting point that Earl Geddes and Lynn Olson agree on (they are of opposing view points most of the time) is that large woofers invite large boxes usually and this is recipe for box modes causing colouration and diffraction issues.
I wonder how much the above are the cause of apparent concerns about using large woofers to run up the horns?
I have only heard the JBL 1500 AL in one diy system that used tad 4003 compression drives, Tad horns and a Tad tweeter. One would be forgiven for thinking the 1500AL is ultimate 15 inch woofer.
As I recall the first and last qualities mentioned above were met with all the glory one would expect but I am not convinced of the other two particularly (given the serious financial outlay given these are soa parts.)
Perhaps Charles is right. Assuming he is then that whole scene is a bit more tricky than comming up with a souped up VOT.
iMac
One needs to remember that ones perception of timbre and image quality is as much influenced by the listening room acoustic as by anything else.
It's remarkable how tolerant we become of our own listening room's additions and how intolerant we are of others.
I personally believe that the compromises inherent in stretching a 15" drive unit to cover half the audible spectrum are no worse than those involved in adding another crossover point with all it's attendant baggage. Certainly all of the four way JBL's I've heard sound like that once "tweaked" by unhappy owners - IE they sound like four separate drive units rather than a homogenous whole.
The system you were referring to was a prototype of mine and whilst the timbre issue surprises as studio engineers and Stereophile reviewers have commented on it's perceived accuracy, the imaging is entirely down to suboptimal positioning required in a difficult room to maintain accuracy of timbre and linear FR. Hence my opening sentence.
Sadly for Earl and others there is no right way to do this - there is no universal panacea as there are no full range drive units capable of flat FR and even power response from 20hz to 20khz at 100db with vanishingly low levels of distortion.
I wouldn't bother... I highly doubt they have anything more to add that wasn't already known going in. The K2 is a product. The questions are: How many units have sold? How many units are selling? What are projected sales? Are we making any money selling them?Originally Posted by Ian Mackenzie
That seems to be the long running argument.
Michael,
Your worship.
Never look up when the Gods are talkiing to you.
It's bad for your eye sight.
Was I specifically referring to you but if you feel as bad as the colour of your own shit then by all means have a clean out!
I have after all visited numerous violent acts of audio stupidity in asia minor over the past 10-+- years.
Your should of course be honoured to be part of end tails.of this thread.
Glad you edited your initial reply Michael but the nearfield never lies.
Was it charged coupled on the initial release or are the rumours of dealers soldering in Hovlands true? Just a question.
The community seeks answers not questions about sales in mother America.
I hope you are not making a pass at the Japanese marketplace.
As posted by an American(s):
quote:Originally posted by Charles Hansen
Well if you want to know what your speakers will sound like, just give a listen to the JBL K2 S9800's. That's pretty much what you've described. The 15" woofer has a paper cone coated with Aquaplas, and an alnico magnet with really cool multi-layer pole piece to keep flux modulation to a minimum.
We used a pair at the CES a couple of years ago and still have them here at our factory in Boulder. (We liked them enough to purchase them.) They have the "Special Edition" crossover that has much upgraded parts over the original version and we also replaced the Monster internal wiring with Cardas.
They're pretty darned good speakers, but certainly not perfect. The main differences between them and what you are planning to do are probably the open baffle (versus a vented box) for the woofer and the horn profiles. But in my estimation their greatest weaknesses (no speaker is perfect!) will not be addressed by your proposals.
To me the single biggest problem of these speakers is that there is *no way* to get a 15" (or even a 12") woofer to sound natural much past 300 Hz, let alone all the way to 800 Hz. But to each his own.
Let me know if you ever want to hear them. We're less than an hour from Fort Collins. From 800 Hz on up, the beryllium drivers create quite an extraordinary result.
Hi Charles, yes, I'd like to hear the JBL K2's. I live in Erie, no more than twenty minutes away from Boulder. You can see my e-mail address midway down the Nutshell High Fidelity website - let's make contact, I'd like to hear the big JBL's. I'm hoping they're in a somewhat higher class than the big TAD system I've heard so far. I appreciate the invite and would like to take you up on it.
I am partial agreement about the big woofers, which is why I'm keeping open the option of a pair of 12" drivers - again, used with a 700~850 Hz crossover. In this frequency range, I am more concerned about box modes than driver resonances.
The box modes in a big studio-monitor (or JBL K2) box are much harder to control, and to my ear, lend an annoying "droning" quality to the sound, a traditional part of the sound of big vintage loudspeakers. These modes are quite apparent when the drivers are pulled and you put your head in the box - you hear a droning, drumming quality to ambient sounds, and the box stuffing and damping, although reducing its magnitude, adds its own dull, murky quality to the droning sound. Many damping materials have their own sonic signature that overlays the basic box sound, resulting in a slow, sodden quality to the lower midrange and upper bass.
I used to be puzzled why these modes in the 300~800 Hz regions were so obstinately difficult to control, until I got MLSSA in 1991 and found it took 2 feet of a wide variety of damping materials to merely reduce the floor bounce by 20~25 dB. I started with what I thought was plenty of damping, several inches of the fancy commercial foam stuff, combined with several layers of audiophile-grade wool felt, and it only reduced the floor bounce by 5 dB or so! It was nearly worthless!
Now, above 2 kHz, then the commercial stuff started to make a difference that was more worthwhile, particularly if you wanted to reduce the slap off the back of the cabinet. But frankly, anything I could buy on the market, had only the slightest effect in reducing the box modes - and the bigger the cabinet, of course, the lower in frequencies these modes are, and the less effective any type of damping, at any price. So all of the fancy damping we see in big box cabinets is mostly effective above 1 kHz, and does surprisingly little below that frequency. What it does do, though, is add odd colorations of its own, which is why lightly damped old-school speakers can sound better than modern, heavily-damped speakers. It's one of those pick-your-coloration things.
All it takes is a little playing around with MLSSA, or any MLS program, and looking at what it really takes to absorb the floor bounce. Since MLS systems can examine the frequency response of the bounce itself (by gating away the direct sound from the loudspeaker), you can examine at leisure what various damping material do in terms of absorption vs frequency. Carpeting, for example, does nothing below 8 kHz - it might as well be glass.
It was this discovery that made me realize just how hopeless the situation with conventional box speakers really is. The only way to get around it is confine the box speaker to very low frequencies (below the first mode) and use a sharp-cutoff crossover to avoid contaminating the more critical region of the spectrum. Otherwise, the box is going to result in murky, opaque, and congested bass - I suspect much of the merit of transmission-line speakers amounts to little more than clever control of box modes in the 300 to 800 Hz region. That's what I had in mind with the Ariel - it was the box-mode region I was most interested in, not the deep bass. Even so, transmission lines have their own set of awkward compromises in this frequency region.
Although I grant that big drivers in the 12 to 15-inch range are starting to get into trouble, with the spider and surround being the first resonance to appear, I feel the box modes are the most prominent and objectionable - and due to the lack of good LF absorbers, the hardest to control. My instinct is that more than 20~30 dB of smooth, broadband absorption is needed, and existing damping and absorbing materials just don't provide that in the box-mode region. Thus, the proverbial "box" coloration which is so noticeably absent in bass horns and dipoles - since we are all so used to this particular coloration, it is most noticeable when it disappears.
For me, the charm of OB isn't so much the dipole radiation pattern, with the claim to less room coloration (which I am not all that sure of), but the more genuine advantage of side-stepping a prominent coloration in a very important frequency range - upper bass and lower midrange. True, driver colorations remain, but I feel these are much milder in the 300~800 Hz region than the much more noticeable 1~4 kHz region, where small-format midbass drivers are commonly used.
Last edited by Lynn Olson on 05-07-2008 at 09:49 AM
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