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Zilch
02-17-2005, 09:20 AM
Article in 2/05 AudioXpress outlines how to upgrade Klipschorn with JBL 2404H.

Conclusion:

"Good horn tweeters are expensive, and the JBL 2404H is no exception. A new pair will set you back about $550. ... In my opinion, the investment is entirely worthwhile."

Oooops! :p

johnaec
02-17-2005, 09:33 AM
Oooops! :p???? :(

John

Mr. Widget
02-17-2005, 09:45 AM
Oooops! :p

???? :(

Widget

4313B
02-17-2005, 09:47 AM
Article in 2/05 AudioXpress outlines how to upgrade Klipschorn with JBL 2404H.

Conclusion:

"Good horn tweeters are expensive, and the JBL 2404H is no exception. A new pair will set you back about $550. ... In my opinion, the investment is entirely worthwhile."Neato! :applaud: Thanks for the heads up! :yes:
That'd raise the net worth of those Klipschorns to roughly $559.98...

Mr. Widget
02-17-2005, 09:49 AM
Tisk, tisk, tisk.....


Widget

Zilch
02-17-2005, 10:21 AM
The Oooops! is for the $$$$. Author waits until the last paragraph to mention THAT part. WE know used ones are available much more reasonably, though. :p

Another good quote:

"The improvement over the [stock EV] T35 is by no means subtle. It is decidely obvious. High frequencies are reproduced with extreme clarity and detail. The assumed excellent dispersion characterisitcs of the bi-radial horn configuration are confirmed too, evidenced by a complete lack of "beaming."

Note: It's not a simple swap. Author designs an builds a new crossover HF section, and describes how to disconnect the HF section of various versions of the stock crossover....

Mr. Widget
02-17-2005, 11:30 AM
Thank god some people buy this stuff new so that we can buy it later used, or better yet unused. :applaud:


Widget

BTW: I read the article and thought it was fairly thorough and well thought out.

HenryW
02-28-2005, 07:24 AM
FYI - I have heard a Klipschorn modified with the 2404 and it is a very nice improvement and well worth the change for any so inclined. Asthetics is the only issue - I have run across the same using the 2404 in my project (pictures of progress coming soon) - it either makes your horn section wider or taller than most other three ways...

jblnut
02-28-2005, 07:35 AM
In my mis-spent youth, I frequented many local hi-fi shops. One in particular was a K dealer and I was once treated to a full-on, glass-shattering rendition of Herbie Hancock's " Rockit" (remember how big that tune was in 1982/3 ? ).
It was so loud that even in my younger and stronger ear days, I was questioning the sanity of remaining in the room.

I don't know how many K's were sold strictly on volume, but it had to be a lot. And somehow *we* got stuck with the "junk but loud" tag. Ain't fair....

I never forgot the K-Horns, and I never bought that album....

jblnut

Al Klappenberge
02-28-2005, 09:37 AM
Guys,


For what it's worth, I don't like going from a horn to a direct radiator in the Khorn. What the Khorn needs is a better horn! Put an Altec 511b in there and the difference will knock your socks off! I have Belle Klipsch with 811b horns, JBL 2426h drivers and Beyma CP25 tweeters. I am also using extreme-slope crossovers (120 dB / octave). The difference is obvious! See: http://www.s114186177.onlinehome.us/ for details.

AL K.

Steve Gonzales
02-28-2005, 04:06 PM
Boy, that is a great looking rig Al, I'll bet that it DOES sound very nice. I am a fairly new convert to compression horns and don't know how I EVER thought that music sounded good before them!. Cone/Dome Lovers: NO OFFENCE INTENDED, that is my taste. Looks like you've had/have some sweet lil' babies to help you critique too. 1 meow= good, 2 meow=bad, 3 meow= are you kidding?!;)

Al Klappenberge
02-28-2005, 04:25 PM
Steve,

Yep.. Those modified Belles are up there with the best of them. The Altec VOT horns are very good. I guess I should admit that part of my business is selling upgrade crossover networks for Klipsch heritage speakers. I am ALK Engineering.

As to the cats, I have only one now, the grey one. The tabby died (had to be euthenized actually) from bone cancer. I still miss her. :(

Al K.

Steve Gonzales
02-28-2005, 04:35 PM
Our kids are grown and gone and now we have our two boys. Here we all are listening to music together. I can't imagine life without them.

Al Klappenberge
02-28-2005, 05:13 PM
Steve,

Here's my new little pest ... oops, I mean pet! He always wants to be in sombodies lap!

Al K.

duaneage
02-28-2005, 06:31 PM
I owned a pair of Cornwall II speakers years ago. I liked the fullness of the sound, the midrange and highs were pretty darn good. The cutoff on the box was 45 Hz but you would not know it from the way the bass would rattle the room. Cabinets were beautiful , I went for the Birch rather than Oak like everyone else.


I ended up selling them when I got married, casualty number 1 of marriage. I think about gettinga pair but they are so heavy I would have to find them within driving range.

I respect classic Klipsch speakers, the HT stuff they make today is really sad.

Al Klappenberge
02-28-2005, 06:44 PM
Duanage,

I had a single Cornwall for a while as a center between the two Belles. I didn't think it worked very well for that, so I sold it for another Belle. It did help extend the bass below where the Belle woofer would go. It just didn't sound enough like the Belle to me.

Klipsch's new stuff is a casualty of the modern market situation. Not to many people go in for the full audiophile experience, i.e. "2-channel", any more. It's all home theater. That is where the money is and where every manufacturer has to go to stay in business. Klipsch is no exception. At least they are still making the heritage sereis after a pause of a year or so when thier driver supplier (ElectoVoice) left them out to dry! They had to go back to Atlas Soundlier for the squawker driver and an overseas source for their tweeter.

Another reason for the changes is the retirement and finally the death of Paul Klipsch. The old man is no longer there to keep their feet to the fire!

AL K.

HenryW
03-01-2005, 05:38 AM
For all - friend Al has a sterling reputation from the Klipsch Heritage folks. Nary a soul complains about his crossover and most extoll the virtues (sometimes endlessly). I have a house full of Heresys and have done a couple of builds with Klipsch stuff - so I have seen some of Al's more detailed conversations as I spend time at the Klipsch forum. His depth of knowledge on crossovers is very helpful indeed. He guided me on taking my new JBL project (built like a 4671 three way) to get a completed box tested to see what tweaks are needed in the network.


Al - your comment regarding horn for horn above regarding the 2404 - Do you not consider the 2404 a direct horn replacement for the K77/T35 on a Khorn? That is the mod I have heard - it clearly sounded better to my ear.

Al Klappenberge
03-01-2005, 05:53 AM
Henry,

To spite your glowing comments about my competence, you may have cought me flat-footed! Maybe I do not know what a 2404 is! I assumed it was a direct radiator. The problem is that I no longer subscribe to AudioXpress magazine and I didn't see the article. I remember a description by John Warren on the Klipsch board advocating two direct radiator drivers to replace the Klipschorn midrange horn and driver (K400 + K55). I just assumed that was what the article was about! If that's the case, I think it's a bad idea! I need to investigate the 2404 before I say any more!

Al K.

Al Klappenberge
03-01-2005, 06:07 AM
Henry,

YES,I blew it!! :banghead:

The JBL 2404 is the baby-butt tweeter, not a direct radiator midrange driver! It's definitly a fine replacement for the K77 tweeter in the Khorn. A far less expensive replacement is the Beyma CP25 though. I use those in my Belles. BUT.. here's where I went wrong: I assumed that the upgrade was about the K400 midrange horn. This is the thing the Klipschorn needs upgraded, not so much the tweeter! I just (wrongly) assumed that's was what the article was about.

AL K.

Mr. Widget
03-01-2005, 10:11 AM
I assumed that the upgrade was about the K400 midrange horn. This is the thing the Klipschorn needs upgraded, not so much the tweeter!

I would agree that since the midrange is the most important part of the spectrum I would tackle it first, but I would say that Paul was even handed in short changing his wonderful design. Had he been willing to offer a deluxe Klipschorn with top of the line drivers this conversation might not take place.

Widget

Al Klappenberge
03-01-2005, 11:57 AM
Widget,


Another thing you got to remember about the Klipschorn, PWK was building it since 1950 in virtually the same form. The parts he used where the best compromisis he could find at the time. The 400 Hz upper limit of the Khorn woofer makes the low end of the midrange very hard to do! A 400 Hz low end on a midrange is still hard even today. That is why I like the Belle Klipsch better. It's woofer will go up to 700 Hz before it starts to poop out! That makes life a lot easier!

Al k.

Mr. Widget
03-01-2005, 12:17 PM
Don't you think a large format Altec or even the JBL 375 could have been used to 400Hz and sound better than the $20 Atlas paging horn driver he did use? I realize that the 375 with it's aluminum diaphragm is pushed at 400Hz, but at the 1-2 watts max that it would normally be required to take in a home setting, I am sure it would be fine.

I must admit, Paul really did make a silk purse out of a sow's ear, and I think that was part of the challenge for him. I think he got a kick out of using average parts and making a system that was significantly above average.

Widget

4313B
03-01-2005, 12:23 PM
There was a whole group of folks back then who thought JBL was out of it's tree for overbuilding such transducers as the LE15A and 375. If I remember correctly J. Robert Ashley was in that group as was Paul W. Klipsch. Mark Gander could probably shed more light on that subject.

Steve Schell
03-01-2005, 01:24 PM
Hal Cox told me a story about the early Klipschorns. Seems he was selling the Klipsch line in San Francisco in the early 1950s. The original two way Klipschorns with the large radial midrange/high frequency horn had been selling well. Then a shipment of several new ones arrived and the design had been changed to the three way model. Hal thought they sounded so much worse than the older ones that he sent them back. He said that Paul Klipsch took it in stride; indeed they remained friends until Mr. Klipsch's death.

One of my favorite soap boxes to stand on is that horn systems have always suffered horribly from attempts to miniaturize them. Generally, bigger is better! I haven't heard an early Klipschorn, but I imagine the mids produced would be much better than the nasty little small mouth mid horns they used later could manage. One of the early two way Klipschorns can be seen on Kerry Brown's site at:

http://homepage.mac.com/ikecarumba/PhotoAlbum19.html

Al Klappenberge
03-01-2005, 01:29 PM
Guys,


Like I said earlier, it's that K400 horn that is the culpret, not the cheap driver! I put Altec 811b horns in place of the K500 horns in my Belle Klipsch and found a big improvement. Later I replaced the Atlas K55 drivers with JBL 2426h drivers. That was an improvement too but not as big of one as the horn upgrade was. I really doubt that PWK would have put in Altec or JBL parts no matter what! He wanted his own stuff even if it wasn't as good! BTW: The JBL 2426h doesn't work well with the Altec 811b horn either. It drops steadly down like mass roll-off. I even had to e-q it to get it to go flat to 7500 Hz!

AL K.

Ian Mackenzie
03-01-2005, 02:36 PM
Steve,

Where do you think the tractrix horn for mids fits in the overall scheme...I'm referíng to the Edgar horns.?

Ian

Steve Schell
03-01-2005, 03:07 PM
Hi Ian,

I like Dr. Edgar's tractrix midrange horns a lot, especially the axisymmetric (round) ones. They have very little horn coloration and will float a large soundstage. One characteristic they have in common with other curved wall horns is that they beam progressively at higher frequencies. Bruce crosses over to his tweeter before the beam narrows much, but even so there is some shift in tonal balance in other than the center listening position. The center seated listener will have big grins however.

The conical horn family is my first choice at the moment. If carefully designed they are almost devoid of horn coloration and maintain very broad dispersion vs. frequency- essentially defined by the angles of the walls. The response measured almost anywhere within their pattern will closely resemble the driver's power response. This is good, as it creates a reverberant field with about the same spectrum as the on axis radiation, which resembles the way sounds propagate in nature. The tradeoff is that they tend to measure with a "goose egg" response curve on axis, due to the relative lack of low frequency loading in the throat and broad dispersion of the highs. It takes a compression driver with an especially robust low end and/or EQ to flatten the response on the low end, and pretty much the same situation in the highs- or crossing over to a tweeter before the driver's power response falls off much.

Ian Mackenzie
03-01-2005, 03:11 PM
Thankyou Steve,

Great reply

Ian

Al Klappenberge
03-01-2005, 03:17 PM
Ian , Stever,

I don't know if you aware of it, but I am working on a Tractrix replacement horn for the Khorn right now. It's described on my business web site (alkeng.com). It's the rectangular mouth type with the fixed flat top and bottom and curved sides. My tests on it show that it's working well but I am having fits getting somebody to make the thing! I'm waiting now for the parts to be made by a local millwork company with a CNC machine. In any cast though, it has GOT to be better than the Klipsch K400 horn. If you read the technical paper PWK wrote about it when it was first release, he made a huge compromise by cutting down the length and counting on the front baffle to extend the low end. This, I think, was the killer! It just doesn't launch the sound waves properly! I am not a horn expert by any means. My bag is passive filters. I'll let the horn experts tell me WHY the tractrix sound better. I'll just be happy to listen to them! Oh yeah, and to make one that will fit in the Khorn!

Al k.

Steve Schell
03-02-2005, 01:23 PM
Hi Al,

Probably the chief reason that tractrix horns tend to sound better than exponentials is that mouth reflections are better controlled. A true exponential horn would never terminate (i.e. opposing sides become parallel) no matter how long you made it. In a finite horn (all of them) there is an impedance discontinuity at the mouth, causing some reflected energy to head back up the horn and change the loading on the driver. Depending on frequency the phase of this energy will cause either constructive or destructive interference of the radiation resistance seen by the driver, causing ripples in the response down near the cutoff frequency. It is good practice to use an exponential flare of one half to one octave lower cutoff frequency than you plan to use, to stay away from this rippled response.

Another problem exponentials have is that they are calculated based on a plane wave propagation. Sound waves inevitably develop a portion-of-sphere shape whenever conditions allow, and an exponential flare has no power to stop this. So, since a bulging wave has more area than a flat plane, an exponential flare effectively has a decreasing rate of flare as the mouth is approached. This may worsen the impedance discontinuity at the mouth.

A tractrix flare has a constantly increasing rate of flare. They are similar to an exponential in the first third or so of horn length, but then they expand much more rapidly out near the mouth. They also do terminate with parallel sides, minimizing the problem of mouth reflections. The net effect is a shorter horn than an exponential with the same flare rate and mouth area, and a smoother response near the flare frequency.

It has been my experience that horns with larger mouths usually sound better, whatever the flare type. I'm fond of conicals with mouth areas of four to five square feet, which is impractically large for most people but sounds great. It is not necessary to go that large with a tractrix, but continuing the mouth with a gentle curve beyond the termination may further aid in disabling any mouth reflections and preventing them from disrupting the driver response. Avoiding large ratios of height to width may also help with a spherical wave propagation; Paul Voigt built his original tractrix horns with a square cross section.

I realize that this all sounds like a recipe for a horn which will not fit into the Klipschorn's upper cabinet. I have always liked the look of free standing mid horns sitting on a bass bin, and this is probably best from a performance standpoint. Another possibility would be to fabricate new top cabinets for the Klipschorns to accomodate the larger midrange horns. I would also look for ways to time align the midrange and tweeter drivers. Despite Paul Klipsch's opinion to the contrary, this has always been a problem with the Klipschorn design.

Al Klappenberge
03-02-2005, 02:58 PM
Steve,

Your technical description of the Tractrix is almost word-for-word how a friend of my explains their advantages. I did a calculation to find the equivalant exponential throat expantion to the horn I am making for the Khorn. The result came out 309 Hz. With a mike in the throat, the response was quite good down to that point. It does seem to be a valid assumption.

The cutoff front of the Klipsch K400 horn is in keeping with the mouth reflections screwing things up. I think that is what's going on with it.

Anyhow, the mouth size was chosen to fill the front of the Khorn top section and the angle on the top and bottom was chosen along with the tractrix expantion to come back to an exact 1 inch square throat. The same program figures the length to transition from 1 inch square area to 1 inch round diameter. Since engineering computer programs is my background, writing a program to do the necessary iterations was only a days work and a fun job too!

Al K.

Al Klappenberge
03-02-2005, 03:05 PM
Here's a picture of the prototype horn mached up inside the top section of a friends Khorn. The tweeter is a Beyma CP25, The netwrok in the picture is half of my 400 Hz extreme-slope job.

AL K.

Steve Schell
03-02-2005, 11:06 PM
Hi Al,

I finally made it over to your site- congratulations on your fine work. I am sure that your tractrix horn will provide a big improvement over the stock horn. I really admire your construction of the dividing networks as well.

Ian Mackenzie
03-03-2005, 03:40 AM
When I have some free time I would like to investigate alternatives for the exponential 2307 horn / lense used in the 4343/4344/4345. In these designs it works reasonably well @ 1250 hz-9Khz but I am sure other alternatives would be very interesting.

Ian

Al Klappenberge
03-03-2005, 04:02 AM
Ian,

You are going to have to lead me by the hand about those model numbers you mentioned. I am not well versed in Altec and JBL history. One thing though, The Klipsch woofer won't go up very high in frequency. Even the Belle Klipsch and LaScala woofers top out at about 700 Hz. Midrange horns rated only down to 1000 Hz or so are out of the question.

Al K.

Al Klappenberge
03-03-2005, 04:55 AM
Ian,

I have had no experience with those acoustic lenses at all. I was always impressed with the idea though. Since you don't see any implementations of the idea these days I just assumed it was a discredited idea. I have found that a lot of good ideas are ignored for bad reasons and a lot of bad ones are promited in the audio field. The slot tweeter idea is one example too. They seem to be popular because of their good dispersion but, at least on the Klipsch forums, most people don't like them.

Maybe the big problem here is the 4-way requirement. That's a lot of filters for a good network. I also would not put a direct radiator on an otherwise all-horn speaker like the Khorn. That would be silly. If you go to all the hell of a folded horn woofer, a horn-loaded top end is a sinch by comparison! Why mix the methods?

Al K.

sfogg
03-03-2005, 07:46 AM
"I would also look for ways to time align the midrange and tweeter drivers. Despite Paul Klipsch's opinion to the contrary, this has always been a problem with the Klipschorn design."

That is what Al's Extreme Slope crossovers address. By dramatically limiting the overlap between drivers you don't get the interference problems of two drivers reproducing the same material with different path lengths to the listener.

Al designed/built the ES600s (600hz crossover point) I'm using with my Klipsch LaScala bass bin and Altec 902-8B/511B upper horn. There is about a 50hz region where the drivers aren't more then 10dB down relative to each other. Their initial slope is on the order of 150dB/octave.

The clarity/coherence in vocals and such was greatly improved moving to this crossover from a first order design.(Also designed by Al)

Shawn

sfogg
03-03-2005, 07:55 AM
Al,

" Since you don't see any implementations of the idea these days I just assumed it was a discredited idea. I have found that a lot of good ideas are ignored for bad reasons and a lot of bad ones are promited in the audio field. "

Kind of OT but check out the lens used in these speakers...

http://www.beveridge-audio.com/White_Paper.htm

Shawn

Al Klappenberge
03-03-2005, 10:14 AM
Shawn,


Hi! Fancy meating you here!

That article is getting into an area I piptoe quietly away from! It is a very deep subject and WAY out of my area of expertice! I am going to keep my big yap totally shut on this one!

Al K.

Mr. Widget
03-03-2005, 10:44 AM
While a cursory glance at the Harold Beveridge White Paper looks remotely similar to papers published a few years earlier by the famous Dr. Bose, I remember hearing the products of Mr. Beveridge's work and they were truly outstanding. They didn't quite have the dynamic range or impact that these horn systems have but image quality, tonality, and detail were mind blowingly good.

Now back on the topic of that K-400.

Here is an on axis plot that I made a while back of a K-400 with Klipsch K55V driver. It performs exactly as advertised by Klipsch at +/- 5dB over it's range of 400Hz to 6KHz but just! Also notice the nasty ringing and or mass breakup up top. This measurement was taken with the horn mounted to a small baffle. (the top panel from a Klipsch La Scala)

Widget

sfogg
03-03-2005, 11:07 AM
" Here is an on axis plot that I made a while back of a K-400 with Klipsch K55V driver. It performs exactly as advertised by Klipsch at +/- 5dB over it's range of 400Hz to 6KHz but just! Also notice the nasty ringing and or mass breakup up top."

Here is the same driver on a 511B run full range....

http://forums.klipsch.com/idealbb/files/k55v1.JPG

Same driver and horn but using Al's 'Type A' replacement crossover which rolls of the midrange...

http://forums.klipsch.com/idealbb/files/k55vk400alk.JPG

Then a 902-8B for comparison on the same horn same measuring position...

http://forums.klipsch.com/idealbb/files/902-8b.JPG

Shawn

Mr. Widget
03-03-2005, 11:21 AM
Shawn,

Is that RTA time gated? If not, you have got all kinds of room interaction going on there. The Altec while more extended appears to be +/- 10dB!!! I hopethat is due to room interaction.

Widget

sfogg
03-03-2005, 11:30 AM
"Is that RTA time gated? If not, you have got all kinds of room interaction going on there."

Not time gated but I don't think there was much room interaction as these were all measured with the mic about a foot from the mouth of the horn.

I don't have the K55s any more or I'd redo it with ETF to gate the measurement.

Shawn

EDIT:

The scale on this one is different but this is the 902-8B on the 511B through the ES600 crossover. With this one the mic was in the horn itself.

http://forums.klipsch.com/idealbb/files/highcross.JPG

Al Klappenberge
03-03-2005, 11:38 AM
Widget,

I recognize your K55 plot. It is typical. It was of the older K55V with the push-pin spring-loaded connections. I can tell by the 9 KHz "glitch". The later version with solder terminals had a 2-piece phase plug and had that glitch worked out.

Al K.