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A time-aligned top end - Part II


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The fact of the matter is Dave and ALK provided huge amounts of the data they have on this project, and by doing that they are now venerable all kinds of criticism.

Criticism or analysis/interpretation? What do you personally want the polars to look like? It's all a matter of perspective...

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Guys,

.A little dose of reality here. Here's the rub... Like I have said before, good engineering is always a balance of trade-offs. If you want at 2-way system you will be stuck with collapsing distribution as frequency goes up. This is what a CD horn is all about. I personally have never heard a full-range one, so I can't say what the down side is myself, but I have heard people say they sound like a frying pan. This is the up-side of a 3-way system. A little tweeter can distribute the highs far better than a big horn like the Eliptrac designed to load a driver to below the Khorn's 400 Hz crossover needs. The Eliptrac will still make a beautiful mid-range horn. Let's not loose sight of the fact that it's the Faital Pro HF200 driver that is letting us do a 2-way system, not just this horn. I still believe in 3-way systems especially when an extreme-slope crossover to a tweeter can make the time alignment issue restricted to just a small window of frequency right at the crossover.

If the tweeter section of the coaxial B&C DCX50 had a high frequency distribution that was better, the phase coherent crossover idea would not be obsolete, but since it's no better than the HF200 on the same horn, why bother with a coaxial? This is what we have accomplished here.

Personally, I will take a good tractrix horn like the Eliptrac in a 3-way system with an extreme-slope crossover to a good tweeter over a time-aligned 2-way where the highs come at you like a flashlight beam or the high end sounds like a frying pan any day! THAT folks, is your trade-off.

For me, the decision is if I will make a step forward in my own system by replacing my Martinelli Edgar type 1-inch Trachorns with the Elliptrac horn or not. Now that Dave has come up with a 'correct" 2-inch down to 1-inch adapter, this is a possibility. I still do not believe a 2-inch driver is needed in a set of Belle Klipsch (or a set of LaScalas). I don't have to cross over at 400 Hz where only a 2-inch driver can operate cleanly. I can cross over to a mid-range at 500 Hz where my 1-inch JBL 2426h drivers can function without distortion. I have already modified the Khorn frames Dave built into the first prototypes of the Elliptrac to fit by Belles. All I need to do is add the 1-inch converter, staple on the grill cloth and install them. SHOULD I DO IT?

Al K.

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This is what a CD horn is all about. I personally have never heard a full-range one, so I can't say what the down side is myself, but I have heard people say they sound like a frying pan.

The CD horns that sound like frying pans are using diffraction slots, which create distortion. You can get a low distortion wide bandwidth horn without a diffraction slot. You can also make a 2" driver that doesn't beam the highs. I personally prefer a little beaming as you go higher in frequency because it sounds less analytical and more warm...and I think drywall is way too reflective above ~5kHz, so it helps tame the off-axis brightness.

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DrWho, I had misunderstood your comment. We are actually in total agreement.I get it now.

Al, yes, always tradeoffs or the perfect speaker would exist and everyone would own one. All others would be obsolete.

Since you have all the stuff and certainly the know how for the crossovers, try the two way down to 1" and see how well it works. At some point we have to leave the scientific data points behind and find out how it sounds to us. And I dare say that the same system in the same room sometimes sounds different to each of us. As you said to me GO FOR IT!

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Basically you have a horn/driver that collaspes it's polars in both the Horizontal and Vertical planes.

mike tn

What is your point? The horns and drivers are JUNK?

The fact of the matter is Dave and ALK provided huge amounts of the data they have on this project, and by doing that they are now venerable all kinds of criticism.

Thanks for pointing out the obvious. Craig!

Why not settle down Johnny 5.

The Klipsch K-402 and K-510 are CD (constant dispersion horns). IOW, the frequency repsonse on-axis is comparable to the FR off-axis (within limits). The horn also needs to control the dispersion (shown by the polars) down to a specified frequency.

In the horizontal plane the the 402 and 510 (almost) control down to about 500 hz. The 402 will also control in the vertical plane down to about 500 Hz. For the 510, it needs to go up about an octave and a half.

The present horn being discussed horn beams at the higher frequencies (dispersion becomes narrower). They are not CD horns. Is this bad in itself? It depends on your design goals. They also lose dispersion-control at the lower ferqeuncies. This last point is mostly a function of its overall size.

The problem with this thread is two-fold. First, there is no notion of a design goal (eg, should dispersion be controlled? should the polars line up at the crossover freqeuncy? etc). Rather, the goal is loosely, "lets try it see how it sounds".

This approach presents difficulties because you don't have a tangible, measurable goal and what sounds good today will change tomorrow. It is easy to hear differences, while it is more difficult to judge whether something actually sounds better over the long run. Most folks don't understand this difficulty and end up changing gear on a monthly basis.

The second problem with this thread is that it is actually a thinly veiled infomercial.

If folks were more up front, then it would be moved to the Garage Sale forum. That said, it is unfortuante that there is not a clearer direction to the effort. The craftsmanship and energy are to be commended, but there is a lack of direction regarding the choices of which horn, which flare, CD or no CD etc.

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Rudy,

I'm not sure what you mean by "try the two way down to 1", The mid-range output of any of my networks will operate the HF200 without any mods. ES400, ES500, ES600. AP12-350, AP12-AK3 ... etc. All will work without modification. So like I said. If you want to try 2-way, GO FOR IT!

Al K

Al, sorry I was referring to your thoughts on trying the 1" adapter on the Eliptrac with your Belles.

As far as two way in my listening room, I went two way last year shortly after starting my journey to the dark side of active filtering. I originally tried two way with my Khorns, but couldn't find a reasonably priced driver/horn combination that could match up with the bass bin. I eventually built JC's DBBs and still enjoy those today in a two way setup with my P. Audio horns. The P. Audio horns have been ok, but as always I'm looking to improve things another notch.

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The second problem with this thread is that it is actually a thinly veiled infomercial.

If folks were more up front, then it would be moved to the Garage Sale forum. That said, it is unfortunate that there is not a clearer direction to the effort.

Wow! I couldn't disagree more. I, for one, found these threads to be informative and an effort by the more knowledgeable folks to find a solution to a common problem for those using two way setups. Infomercial....you have got to be kidding me.....that's actually funny.

Al and Dave and many others who build and create stuff are some of the most helpful and selfless folks I have ever dealt with. I believe your accusation to be way off base. I am glad they come up with this stuff and make it available to those of us who don't know how to build networks or horns or speakers.

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Why not settle down Johnny 5.

I really shouldn't even have commented here, because I know Dave personally. Oh well, too late now.

In the horizontal plane the the 402 and 510 (almost) control down to about 500 hz. The 402 will also control in the vertical plane down to about 500 Hz. For the 510, it needs to go up about an octave and a half.

I would still like to see the Polars and curves, These CD horns get an awful lot of praise for no one to have any graphs on them.

Rather, the goal is loosely, "lets try it see how it sounds".

The goal as I see it is a Time Aligned Top end.......For KHorn I believe was the original goal.

This approach presents difficulties because you don't have a tangible, measurable goal and what sounds good today will change tomorrow. It is easy to hear differences, while it is more difficult to judge whether something actually sounds better over the long run. Most folks don't understand this difficulty and end up changing gear on a monthly basis

Cant argue on this one, I have tried several horn and drive combo's looking for the best sound. So far my preference is the Tractrix 3 way, as I have never heard a 2-way horn system I liked. (never heard Jubs with a 402) however since there is no perfect horn, its back to a balance of compromises.

The second problem with this thread is that it is actually a thinly veiled infomercial.

This accusation get used every time ALK voices his opinion, I have used it myself in a heated argument with ALK.

Let me first point out this thread started as a 3-way time aligned top end for a KHorn where a 2 inch rectangular tractrix was being used with a coaxial driver, and ALK designed a "phase coherent" network....whatever that is. Now its has a different horn and driver ALK doesn't sell, and can be used with a crossover he has been building for years. Anytime you provide information, the information becomes an infomercial for the product you are testing, good or bad. (how many phase coherent networks and B&C drivers do you think ALK is going to sell now that he called them a mute point?)

That said, it is unfortuante that there is not a clearer direction to the effort. The craftsmanship and energy are to be commended, but there is a lack of direction regarding the choices of which horn, which flare, CD or no CD etc.

This thread has gone a few different direction, however I was under the impression all of the horns used here were tractrix. Maybe I dont understand the question.

Tom , you bring up alot of good points, from clearly a different perspective.

Craig 73

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It seems like good information has been presented in this thread that a person involved in DIY modifications could consider when developing their specific design goals (including the polar information from Lee and Mike's perspective as it does help a person "visualize" when thinking about cross-over points and room interactions). I thought that I saw the program code used to cut the pieces for the horn for the CNC unit posted somewhere in one of these threads and, when time permits, I have thought about using my uncle’s CNC to try a DIY project.

Currently I’m building clones of the First Watt F3 and F5 from the schematics posted on the DIY site, but not everyone can take the schematic and be successful. If we can keep the information and subsequent analysis/interpretation in the proper context (I realize that my "locks" only keep honest people honest and have very little impact on the dishonest), the information in this thread can help many.

For me, it’s nice to know that there seems to be enough information in this thread for the DIY type of person and most of us "are aware" and appreciative that there are avenues for the non-DIY person that may be interested in performing a modification (I'm not the person that says or wants to imply that "if you are not technical, you have no right to modifications" and see the contributions of Al, Dave, both Mike's and others as very valuable to the "updates & modifications" forum). However, at some point, just like anything in life, “caveat emptor” - let the buyer beware that he/she buys/plays at their own risk (I've been sucked into the "hype," but my F3 and F5 could ultimately be a waste of time and money for me just like modifications could be a waste for some, but a very rewarding experience for others)….

I really enjoy viewing the measured data and the subsequent analysis/interpretation aspect of these threads, have learned a lot over the years and always hope the analysis can be balanced and informative in helping others make an informed decision for themselves. However, too many times people "appear," under the "guise" of "interpretation" or “protecting the naive” or "discredit the OP," too interested in “trying to prove” that they have the “best, most excellent, top, finest, greatest, unsurpassed, paramount, preeminent, superlative, only, right, correct, etc.” view….pick the adjective that pleases you the most…..but at the "end of the day" they are only presenting another choice or option. I'm glad I live where I have choices.....

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Guest David H

The Faital Pro is an amazing wide range neo magnet compression driver with lots of potential.

When you purchase the faital pro, you not only get a great driver you also get an amazing booklet showing the drivers full potential(specs), and a handy cardboard carrying case. (box)

but thats not all, if you order right now,

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I know you think this is an amazing deal, but it's not over yet.

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I know you are ready to order right now but wait, this amazing deal gets even better. You can order a pair of drivers for twice the price.

I know, I know, this deal is too good to be true.

What an amazing value. [:o]

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Guest David H

Lee Clinton, has been a huge help taking measurements. Thanks.

I am pleased that Lee was able to confirm ALK's measurements, and the Faital pro will operate down to 400hz witout breaking up.

Dave

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Guest David H

You can order a pair of drivers for twice the price.

unbelievable

I know smoking deal huh.

BTW, thanks for running the curves on the Eliptrac and the K-69. The information was helpful.

Dave

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FREQUENCY HORIZONTAL VERTICAL

400hz 100 degree 120 degree (approx)

1250hz 80 degree 80 degree

3150hz 54 degree 44 degree

6300hz 45 degree 25 degree

10000hz 38 degree 26 degree

12500hz 28 degree 16 degree

20000hz 44 degree 40 degree

Here is my calculation of the DI per frequency using an average of the vertical and horizontal dispersion:

400 Hz = 5dB

1250 Hz =7dB

3150 Hz = 9dB

6300 Hz = 10dB

10.0 kHz = 11dB

12.5 kHz = 12dB

20.0 kHz = 9dB*

*I think the 20kHz point has a loss of resolution
because we know that the sound should be getting narrower at that point
given the horn/driver geometry and frequency response. I'm thinking the
44x40 polar is taking the edge of the first comb-filter lobes instead
of the main lobe. The main lobe should be closer to 20x10, which would
yield 13dB for the DI.

Relative to 1.3kHz, the 12.5kHz raw plot is down about 6dB, so on
a true constant directivity horn or plane wave tube, you're looking at
roughly 11dB down at 12.5kHz for an 80x80 coverage pattern, which is a
similar DI for a 90x60 horn, and is in the ballpark of most modern 2"
compression drivers intended for tweeter use. You will get less cone
breakup from drivers costing more (like the B&C DE1050 for $600)
with the same HF extension, but the HF200 looks like a real good
compromise for only costing $300.

I'm personally going the route
of a midbass to cover 80-1kHz, and then a 1" BMS ($150) to cover 1kHz to
20kHz, and then a killer sub for 80Hz and below. This will get me good
polar control from 20kHz down to 400Hz or so, and then the room corner
will take over the DI at the lower frequencies.

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The skills of the recording engineers and producers generally determine what you'll get out of a recording (performar talent is an underlying or b'ackground' assumption).

Ideally, a great recording should be able to give a listener the experience of sitting in the 'sweet spot' of an excellent performance hall. Since most people don't listen to music in anything like a great concert hall, and probably don't get many opportunities to experience live music at the optimum points in those halls even if they go there, the potential for a recording to meet or exceed the quality of live performances likely to be experienced by a typical listener is huge.

In an audiophile context, being able to leverage a well engineered/well produced recording to maximize the quality of the listening experience (get as close to being in the ideal spot in a great concert hall) is probably the answer to ''What, then, is it that we are trying to recreate with two speakers?''

That being said .... most of the recording engineers and producers today are producing and engineering for the (largely 'tin-eared') iPod/MP3 market -- with almost zero-db dynamic range, heavily reverbed mid-range, boomy bass, etc. (none of which may matter much, since most of the 'music' is electronically generated by computers, and many of the 'vocals' are so heavily 'processed' that they might as well be computer generated [comng in 2012: will HAL-9000 and the 'Lost In Space' Robot team up for Beatlemania?]). The results are predictable: overall music sales have dropped by 9 - 10 percent annually in each of the past 6 years, led by a 17 - 22% drop in new music sales.

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