Oh certainly I hear the harshness too. The clarity is very real though. Remember those expensive and,cumbersome speakers have been in production for 60 years with very little marketing. This is no accident. Point is the baby should not be thrown out with the bathwater.
[:DQUOTE=dumptruck;3666611 said:
The main design that Paul Klipsh was known for was his K-horn bass section.
Unfortunately for that design it is tremendously room dependent.
The upper freq sections of those speakers was not terribly notable.
The original K-horn used a K-55 (Atlas) phenolic driver (which happens to not be terribly bad at all) and a rather horrific EV horn loaded affair for the "tweeter".
Other than doing a good job of marketing and turning a virtually dead brand into a marketable brand (in the last two decades of the 20th century), I'm not sure what there is to point at in the vintage Klipsh engineering?
Unfortunately for that design it is tremendously room dependent.
The upper freq sections of those speakers was not terribly notable.
The original K-horn used a K-55 (Atlas) phenolic driver (which happens to not be terribly bad at all) and a rather horrific EV horn loaded affair for the "tweeter".
Other than doing a good job of marketing and turning a virtually dead brand into a marketable brand (in the last two decades of the 20th century), I'm not sure what there is to point at in the vintage Klipsh engineering?
I would worry more about the air gap at the woofer voice coil. This is unavoidable and I suspect the bigger problem than the cone motion, which, as you say, could be resolved. The leak into the voice coil can't be resolved as far as I can tell.
I've built a couple unity horns with ribbons.
Worked pretty well.
Ribbons solve a couple horns problems. First, the diaphragm is a good match for a horn. Dome tweeters don't work well because the tip of the dome is closer to the listener than the edge of the dome. Half an inch probably doesn't seem like much, but at 20khz, that's almost a full wavelength.
So a ribbon has the right shape. Admittely, flat and round would be better than rectangular.
Another nice thing about ribbons is that there's no phase plug. That allows for a very clean CSD and allows for tight spacing in a Unity horn.
If you have the corners and want that efficiency there is every good point. If Danleys speakers turn out to be the ticket there will *actually be no point*. In reality, we have been using 2 way CD speakers like the Genelecs in the studio for decades and they do not have the impact of large horns. Damn sight flatter though (-: Now here is a fact. I "temporarily" replaced the shitty T35s with a very good piezo in the 90's and there it stayed until Katrina ate the Khorns.
Another fact: T-35s need to have the diaphragm centered properly in the gap, and the proper shim depth for their response to be decent.
The response can range from awful to pretty darn good depending on how the driver is put together.
That said, when done as well as possible the little diffraction horn is not all that good, the T-350 (using the same diaphragm) is a much better horn.
And while we are looking at properties of K-Horns, a standard round Motorola Piezo would actually match dispersion of the mid horn at the crossover point better than the T-35 diffraction horn, or the piezo horn that was similar size and shape to the T-35.
A uniform dispersion pattern is not something one finds in a K-horn..
And that is exactly what I did, looked at the shape and replaced accordingly. I do have the T350's in the sentry's and you are so right it took me several attempts to get them centered, had to break the mags loose from the plates too. I suspect the Eminence apt 50 would do better adapted to that lens maybe.
A foam ring? Or simply bond a flared cone of paper to the outer periphery of the throat, to which the cone is attached (with a flexible bridge).
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Rubbing on the voice coil? Doesn't sound like a good idea to me. Better would be ferro-fluid, but that has some issues as well.
The story (or urban myth) is that Klipsch would tet and reject 1/3 of the tweeters from EV due to quality problems.
My understanding is that the issue of matching driver dispersion at the crossover frequency was not fully appreciated until JBL made a big deal of it back in the 70's (well after the design of the K-Horns). Of course, after this time Klipsch did design and use CD horns in their later designs.
Interestingly, Paul Klipsch was working on a CD horn (midrange) back in the early 60's (BTW, non-diffraction CD horn).
I only bring this up becase it is a bit annoying to hear second guessing about an engineer who did make a difference just using his brain and a slide-rule.
Yes it does.
We are used to changing the oil in our automobiles, but I hate to take apart a working speaker just to replace the ferro-fluid.
The ten Eminence APT drivers I own all have different frequency response, I wonder how much is due to voice coil difference/alignment and how much is due to ferro-fluid degradation and initial "dose".
Patrick thanks for the photos and notes of the ribbon on the Unity horns. Those look like the Fountek ribbons, right.
I've been wondering how they might do on a big horn, but don't really want to cough up enough money to purchase them just to experiment.
I've been wondering how they might do on a big horn, but don't really want to cough up enough money to purchase them just to experiment.
I went through ferrofluid hell working on some Matrix 3's. I have 5 tweeters for them,. None contained the same amount of fluid, some looked more viscous some looked cleaner, all has slightly different spectra with white at *low* end of range. I ended up replacing the stuff a drop at a time at the vc until each diaphragm required the same amount of resistance to drop in the gap, at that point they also measured about the same. I can't imagine that this gets done correctly at the factory any other way. I have a lot of doubt about the regularity of most ferrofluid tweeters. At the same time I'm saying I'm looking straigh at a pristine a set of original Peavey 22a's with the huge square magnet and al diaphragms and salt shaker rig that I intend to try on some EV whales from 450 to about 7k and I am thinking of doping/damping them with it. That may be a better less taxing job for it and I can easily wipe it off.
Did they sell them here under the name "SLS" or "SIS"? I once saw a pair of speakers with a logo that looked like one of those two combinations at a concert, and a tweeter that looked like a larger version of a HiVi RT2.
Also, Peavey has PA speakers with horn-loaded Fountek ribbons in them. No idea if they're any good. I only know the ribbons are Fountek because Parts Express is selling closeouts.
People tend to underestimate Peavey tech in general, a lot of it started early on when he was competing with the big boys and they didn't like it, even quashed his purchasing drivers forcing him to do his own. They can surprise you. Heard a set of Versarrays recently used as hifi speakers along with Sunfire subs. The tweeters were impressive, probably blow-upable on stage ergo parts express closeout.
Sounds about right. I can't find them on the Swans Hi-VI website anymore. 3 or 4 ribbons in a horn, IIRC.
Once again Patrick, where do you get these assumptions from?
Is it from Beyma's white paper?
http://www.beyma.de/fileadmin/seiten/download/pdf/Beyma_2010/TPL-150_en.pdf
All I see there is a comparison with a unknown 3" Ti diaphragm compression driver, with different time scales, and a strange "plateau" is the first ms for the TPL150 (which if real would cause more prejudice than even a long tail happening under -30dB).
Truth is CSD can be arranged to show about anything the person choosing the parameters wants to show...
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One of my concerns about the Danley design, and any design that puts LF drivers, or MF drivers in with compression "tweeters" is the pressure in the horn impinging upon the diaphragm of the HF driver. Danley explained this in another post by saying that the ratio of energies going from the diaphragm out was so high that coming back in there would be very little energy for IMD.
With a ribbon in the same hole, I wonder if it is going to still work.
My idea would be to test this is to run the Danley style horn with the HF off, the rest on, and use the diaphragm of the HF section as a microphone to see what is or is not being sent back. Alternately place a microphone set to a suitable FFT analyzer in the position of the HF section...
With a ribbon in the same hole, I wonder if it is going to still work.
My idea would be to test this is to run the Danley style horn with the HF off, the rest on, and use the diaphragm of the HF section as a microphone to see what is or is not being sent back. Alternately place a microphone set to a suitable FFT analyzer in the position of the HF section...
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