Bob, Dean, and Al... x overs

[IndyKlipschFan]

I want to hear from you... Why you like your respective x overs and more important why?

Paul changed the design in his x overs as parts changed, drivers got better, so it is only fair to explain in "beginners language please" the differences you employ.

For the "semi educated" the easier non too tech language is appreciated. I am sure we all will learn something from you all as well as hear from others, too, as they chime in with their own experiences.

[m00n]

<=== m00n sits waiting to learn something good.

[Speedball]

If they told us then they should be paid for teaching-no?

When my mechanic work's on my car I do'nt care how he does it as long as he does it and I'm happy.

May be sort of like asking a brain surgeon - How did you do that?

[Marvel]

Before they chime in here, I think they have stated some of this:

Dean -- has been doing the rebuilds with better parts (PWK was always doing the cost/performance thing, which a business has to do)

Bob -- same thing. The old designs weren't bad, just replace with parts that are within spec.

Al -- Same as above for some, plus new designs that offer better performance, i.e., the Extreme Slope Networks that cross over steep enough that there is no interaction between the different components (woofer upper end mixing with mid horn lower end).

Al's probably have more design work going into them (ESNs), but Dean and Bob are also smart cookies. You could also toss in some of the work that John Warren has been doing on crossovers.

All these guys are great and we are the beneficiaries of their hard work.

Marvel

[BEC]

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On 3/18/2005 12:49:52 AM IndyKlipschFan wrote:

I want to hear from you... Why you like your respective x overs and more important why?

Paul changed the design in his x overs as parts changed, drivers got better, so it is only fair to explain in "beginners language please" the differences you employ.

For the "semi educated" the easier non too tech language is appreciated. I am sure we all will learn something from you all as well as hear from others, too, as they chime in with their own experiences.

----------------

Well, what I am doing on crossovers is pretty easy to explain. I believe that PWK made good crossovers that worked very well with his speaker designs. His designs have an approach that used just a few parts and that appeals to the old "keep it simple" part of me. Problem is that by now almost all the crossovers Klipsch built more than 20 years ago are out of spec mostly because of the caps becomming resistive from aging. That is not the fault of the design, but rather just what happens to old capacitors.

So, what I am doing is just trying to build the crossovers like PWK built them using the best parts I can find. Notice I did not say "the most expensive parts".

Rebuilding the old crossovers is also something that I like to do. That just takes replacing the old caps and replacing some of the wiring. Gets you to about the same place as a completely new crossover and is not expensive.

Bob Crites

[Al Klappenberger]

Guys,

OK.. Here's the straight dope. I have always said that what I have done is

apply microwave techniques to audio. Here is a page from a book written by

Matthaei, Young and Jones titles Microwave Filters, Impedance-matching

networks, and Coupling structures. It is the microwave filter designers

Bible. This what I do with ALL my designs. NONE of the Klipsch designs are

done this way. This is why mine are constant impedance.

I will try to translate the techno-babble:

"Diplexer with contiguous pass band" = a device that separates a incoming

signal into separate frequency range outputs where one range transitions

smoothly into the other with no gaps or glitches. That is, a crossover

network.

"multiplexer" = many output frequency bands, 2, 3, 4 or more. A "diplexer"

is 2 outputs.

"Singly loaded prototype" = a lumped component lowpass filter designed to

operate from a voltage source (like a power amplifier) into a specific load

impedance (like 8 ohms). NOT from 8 Ohms input to 8 Ohms output! These are

generally boiled down and tabulated to 1 Ohm impedance and a frequency of 1

radian / second (.159 Hz). My computer program (PCFILT) synthesizes them on

demand.

"Mapping procedure" = the mathematics used to predict the attenuation at any

frequency of a filter scaled from the "prototype" lowpass filter.

"Eqs. (16.04.2)" = This is the specific "mapping" formula to determine the 3

dB point on the "prototype" lowpass where BOTH the highpass and lowpass need

to be desinged for.

Al K.

[colterphoto1]

Indy, why ask the guys to discuss their theories, techniques and results again? Here are a few recent threads:

Mod RF7 xovers-

http://forums.klipsch.com/idealbb/view.asp?topicID=54918&forumID=66&catID=19&search=1&searchstring=&sessionID={19B4B7B7-37CE-49E0-BE5E-7C8AAEF99AF5}

Why mod K xovers?

http://forums.klipsch.com/idealbb/view.asp?topicID=54918&forumID=66&catID=19&search=1&searchstring=&sessionID={19B4B7B7-37CE-49E0-BE5E-7C8AAEF99AF5}

ALK xovers-

http://forums.klipsch.com/idealbb/view.asp?topicID=59652&forumID=71&catID=19&search=1&searchstring=&sessionID={19B4B7B7-37CE-49E0-BE5E-7C8AAEF99AF5}

A, AL, ALK xovers-

http://forums.klipsch.com/idealbb/view.asp?topicID=15027&forumID=71&catID=19&search=1&searchstring=&sessionID={19B4B7B7-37CE-49E0-BE5E-7C8AAEF99AF5}

SEARCH for crossovers and you'll get tons of info, most of which is located on the Mods column. Good shopping.

Michael

[Colin]

I like the question, and I like the answers. I knew the differences in their approach, from reading the posts, but having it stated is nice.

BECs work is certainly reasonable and a bargain. If you like the sound, but need to refurbish your ageing crossovers, he is the man to see.

I heard Dean's RF7 crossovers at preacherman Daddydees May 2004 Klipsch gathering in Little Rock, Arkansas. He doesn't merely replace the existing parts, he improves it dramatically. We all heard and liked the improvement. NOBODY said they liked the stock Klipsch crossover better.

Please note that in ALK's technical answer, he achieves a constant impedance; something all amplifiers love, but which flea-powered or tube or both amps need. ALK also works with other lens and drivers. If you are upgrading your classic Klipsch corner Khorns, his Extreme Slope crossovers work with Altec lens and Beyma tweeters. ALK is also working on a wood lens for the Heritage series (and I imagine a new crossover will result.)

[cjgeraci]

Don't forget the newest entry from Dean, the DHAXover.

http://forums.klipsch.com/idealbb/view.asp?topicID=61481&forumID=68&catID=19&search=1&searchstring=&sessionID={3015806B-EB50-4464-AAE5-549673E48E8E}

Frzninvt has had a pair on his '77 Klipschorns, and I've had a pair on my '76 Belles for about a week. Originally designed by John Albright for tube amps, this crossover also shows the amp a constant impedance.

Frankly, I'm pleasantly surprised. Dean sent me a version tweaked for high-volume applications given some of our struggles with the mid-horn. Very detailed at lower volumes (especially for classical), yet these crossovers get up and go when you pound it (or classic rock it)- smooth all the way up. I will do a more detailed review as soon as I get caught up on my basement demolition (and my latest Cornwall mod). Currently, the Belles are run by a Jolida JD100 (Mullard CV4004s) with a Peach (Mark's stock tubes), and a Marantz 8B (with some good stuff in it).

I also plan on hooking up solid state to the DHAXover (my Rotel 200 watter), just for grins, to see how they handle that application.

Carl.

[Marvel]

I think that the DHAXover from Dean is actually a design from John Albright.

Marvel

[Frzninvt]

Marvel,

Carl did mention that. See:

Originally designed by John Albright for tube amps, this crossover also shows the amp a constant impedance.

[Deang]

"I also plan on hooking up solid state to the DHAXover (my Rotel 200 watter), just for grins, to see how they handle that application."

Oh Man, I don't even want to think about it. Remember, it's a first order network -- and that bulb will go if it heats up too much. A 100 watts is all you get! If you fry them, I'll be forced to punish you with Zeners.

"He doesn't merely replace the existing parts, he improves it dramatically."

Colin, what you heard with the RF-7's last year WAS a part for part replacement using parts with IDENTICAL values as the originals, with the exception of one (1) resistor -- which was 1.75 ohms as opposed to 2 ohms. Trey did a transfer function analysis on one of my networks in Indy last year, and the curve did show a near 1.5db drop in output at 3.5kHz, which was certainly caused by the change in the resistor value. I will leave it to you to decide if this what accounted for everything you heard that day, or whether it was a "real" improvement or not. Incidently, I initially modded my RF-7's without the resistor mod, and the change was still pretty impressive.

[cjgeraci]

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On 3/18/2005 2:02:08 PM DeanG wrote:

"I also plan on hooking up solid state to the DHAXover (my Rotel 200 watter), just for grins, to see how they handle that application."

Oh Man, I don't even want to think about it. Remember, it's a first order network -- and that bulb will go if it heats up too much. A 100 watts is all you get! If you fry them, I'll be forced to punish you with Zeners.

----------------

Ok, ok, ok. I'll either be reaaally careful OR just scrap that idea.

On second thought, maybe the Rotel will remain with the RF-7s as backup duty (since the Marantz is doing such a great job with the Belles).

Carl.

[Colin]

DeanoGod, I don't know electronics, but your crossover looked about twice the size of the RF7 one and everybody noticed the difference! why? because of a small attenuation in the upper mids?

[Colin]

"Bob and Michael Crites were there. At the ARK gathering (May 20040), DeanG first played an obnoxious Led Zepplin (?) recording, where Robert Plants voice drove the refined older ears from the room. It grated the ears, ringing like large bell sounding like hiss. Then Dean installed his larger crossovers in Streams (Stream) RF7s. This made a huge difference in the smoothness of the mid-range, but also the treble. Cymbals sounded like metal, NOT hiss. The mid-bass didnt seem like larger to me in that brief glimpse, but it did seem to extend lower a bit better. The group that left, returned; the easy consensus was that the new larger crossovers made a significant difference. NOT as startling as a different amplifier or adding a sub-woofer perhaps, but a definite refinement. If the harshness or brightness of the FR7s are bothering you, this is certainly one solid improvement. After the brief audition I had of Deans crossovers in the RF7, his crossovers are certainly one of them ."

[Deang]

The difference in the size of the capacitors was because of two things: 1) The stock capacitors are 100Vdc, and the ones I use are 250Vdc, and capacitors with the same capacitance value, yet with different voltage ratings -- are not the same size. 2) High quality metallized polypropylenes use thicker polypropylene film.

Since the caps I use are both higher in Vdc, and incorporate the use of thick virgin film (as opposed to recycled) -- they are substantially larger. Polypropylene film and tin foils are even bigger still, because the film and foil are actually separate sheets rolled together. Some capacitors, like the smaller value RelCap PPT Thetas and MultiCaps are actually double rolled.

The caps I use (Auricaps and Kimber) are not "the best" caps, nor are they the most expensive. When recently comparing what I use, with some of Bob's GE Motor Runs in a Type E network, I found little if any difference at normal volume levels. I actually thought the GE's had more detail at very low volume levels. I perceived a smoother sound from my caps at higher SPLs, but it wasn't a make or break issue. I heard "differences", but none of the variations I tried sounded "bad", or "objectionable". I may go back and revisit the issue this summer, but right now I'm just too busy to worry about it. If Bob's market share continues to grow, and I run out of work -- I will come out with a new cap report once again denouncing the use of washing machine caps in loudspeaker networks.

I guess my thing is offering what I consider to be a highly finished product. All connections are gasless, I use some of the best solder available, the least amount of connection points, the least amount of wire possible, stainless steel screws (ooh - ahh), and I even put rubber footy things on the bottom of my boards (when I can find them). For all this attention to detail, you pay twice as much -- and get yellow caps too!

BTW, those of you thinking about dumping your old motor runs and replacing them with new caps -- don't stop there. Take the extra step and dump the T2A in favor of one of the new UT autoformers.

[Colin]

safe to say then that neither you nor BEC are changing the topologies? only the parts?

[dodger]

----------------

On 3/18/2005 10:37:20 AM colterphoto1 wrote:

Indy, why ask the guys to discuss their theories, techniques and results again? Here are a few recent threads:

Mod RF7 xovers-

http://forums.klipsch.com/idealbb/view.asp?topicID=54918&forumID=66&catID=19&search=1&searchstring=&sessionID={19B4B7B7-37CE-49E0-BE5E-7C8AAEF99AF5}

Why mod K xovers?

http://forums.klipsch.com/idealbb/view.asp?topicID=54918&forumID=66&catID=19&search=1&searchstring=&sessionID={19B4B7B7-37CE-49E0-BE5E-7C8AAEF99AF5}

ALK xovers-

http://forums.klipsch.com/idealbb/view.asp?topicID=59652&forumID=71&catID=19&search=1&searchstring=&sessionID={19B4B7B7-37CE-49E0-BE5E-7C8AAEF99AF5}

A, AL, ALK xovers-

http://forums.klipsch.com/idealbb/view.asp?topicID=15027&forumID=71&catID=19&search=1&searchstring=&sessionID={19B4B7B7-37CE-49E0-BE5E-7C8AAEF99AF5}

SEARCH for crossovers and you'll get tons of info, most of which is located on the Mods column. Good shopping.

Michael

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Mike:

In asking in the fashion as was asked, any one of the three could elaborate a bit more. OR since those publishings, they may have found something different to change.

It's a good open thought process, but in asking all three at once WHY they feel theirs are better, that can take a different approach and offer different parameters.

All three answers are good, I understand Al's answer but not a complaint, could you put a little more of your own thought process in?

Extending the question how important do you all see as changing :

The K-Horn

Belle

LaScala

It's not often that three smart, very capable and open people to answer in a "Forum" setting.

All three should be hanked for what has been asked / answered so far.

mOOn also has a thought that is waiting to come in, probably after all of the questions have been asked if there are more than mine.

Pricing is an area understood to be not answered as there are three methods, four if adding a rebuild if he would do so vs what Al can make.

dodger

[Marvel]

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On 3/18/2005 1:27:14 PM Frzninvt wrote:

Marvel,

Carl did mention that. See:

Originally designed by John Albright for tube amps, this crossover also shows the amp a constant impedance.

----------------

Oops!

That's what I get for sneaking in online time at work, heh?

My apologies.

Marvel

[Olorin]

Dean, can you elaborate on the UT autoformer? Is that a brand? Where could a guy get them?

I think my Heresys want a freshening.