Heritage crossover history

[colterphoto1]

Question: without discussing the material in capacitors or any discourse on new or different crossover topologies, can anyone explain the evolution of Klipsch crossover in the Heritage series? (Khorn, CW, LS, Heresy, Belle)

This would aid users in gaining a basic understanding of their crossover networks as originally conceived by PWK. Listeners like myself who have multiple speakers of a variety of eras could decide which style of crossover best suited their listening style and make modifications based on good information.

i.e. In the Cornwall series, the crossover went from B to B2 to B3. The explanation might go thusly.

The input was routed to A, where it sent to a B value choke, creating a low pass filter for the woofer of 6 db/octave, beginning at 600 Hz. THe signal was sent to C value cap , creating a high pass filter for the squawker of 6 db/octave, the squawker was allowed to run unimpeded until its useful frequency range ran out around 6kHz. The signal was sent to D value cap creating ......

In the B2 the following was changed.........

Thanks guys.

Michael

[BEC]

"The music goes 'round and around

Whoa-ho-ho-ho-ho-ho

And it comes out here"

[sunburnwilly]

Michael , I am curious as well . I will say that the AB networks in my rear Belles are crazy looking things , and this pic does not do them justice .

[colterphoto1]

Nice Bob, but seriously, I wonder which model I should settle on. I'll have 5 CW's in my HT, but right now they're all different vintages. I should think that it would help with timbre and voicing if they all have the same crossover and drivers, yes? But which one should I pick? My arsenal right now is 9 CW, 6 LS, 6 H. Where do I start? Almost no pair has the same crossover as another.

I understand that the 'old fashioned' xovers were mostly 6db/octave units, for a smooth transition between drivers. But theoritically, I understand the problem with this and the move toward more 'extreme' slope crossovers. So should I opt for whatever B network was 12 db/octave, therefore staying withing the boundaries of PWK's designs with a bit of tweak for the sake of moderating distortion and timing differences by having two drivers playing the same tone?

This is why I asked the question in the fashion I did. Even if I were to have BEC or Dean rebuild or build networks, I'd like to be armed with this information.

Please help.

Michael

[BEC]

Michael,

Even if you standardize on one type crossover for all the Cornwalls, I am not sure that would exactly do it. Aren't some of yours the 1.5 variety? If so, you have some driver differences. Now, I don't think you would hear a difference in them with, for instance, all type B crossovers, even if you have a K57 or two thrown in the mix, but can't say that for sure.

Now, if all were exactly the same with K-33, K-55V and K-77, I think with all new or newly rebuilt Type B crossovers, you would be in for a sonic treat. That treat might also be close to the same with a Corn 1.5 or two thrown into the mix.

Bob

[colterphoto1]

Bob, thanks, but my old 63's have the VERY old B's in them, and I have some B2's etc. Can you tell me the basic difference in the B/B2/B3?

I think that knowing about the 9kHz glitch in the K55 with spring terminals, I'd want a network that had a low pass on the squawker so it would roll off. Perhaps this would account for some of the harshness in my Yamaha receiver, that it's really a crossover/mid driver problem? I'm just guessing here.

Also, with modern thinking, wouldn't I be better served by 12 db/octave slopes whereever I can? Again I don't want to vary from PWK design, just pick the right one.

I have enough variety of drivers etc, that I think I can swap around to make things work. Have extra stock of K55, K52, K77, K79 etc.

Michael

[BEC]

Well, I think I can tell you the basic audible difference between the B-3 and B. Compared to the B, the B-3 brings the tweeter in later and ultimately runs the tweeter higher compared to the Type B. The B-3 also rolls the woofer off quicker than the B.

The B-2 also brings the tweeter in slightly later, but not as late as the B-3. The ultimate relationship between tweeter and squawker are about the same in the B and B-2. Woofer is probably not audibly different between the B and B-2.

Is summary, B-2 is very much like B. B-3 will run the tweeter somewhat forward compared to the B.

PWK did not address the (probably inaudible) 9 khz glitch that occurs in approximately 20 percent of the K-55Vs.

Bob Crites

[colterphoto1]

Bob,

I think what I'm hearing is:

Leave factory drivers and crossovers together. Freshen all caps. Don't change anything else. Match pairs and front/rears in terms of drivers/xovers whenever possible. But don't mess with the factory mix within a cabinet.

I've already noted that verticals make very poor surround speakers. I'm thinking of maybe using them in front as an experiment. I've got 1 pair verts and 3 pair horizontals and parts to make center (don't know which direction the cabinet will face.

Is there any easy way to tell which K55's might have the 'glitch'? can I run a series of test tones (I have a synthesizer) to see which might have the 9 kHz thing?

Thanks,
Michael

[BEC]

Michael,

That is where I would start. The fact that they need new caps could be considered a given.

If I had ever been able to hear the storied glitch, I could answer that one, but have failed miserably in trying to hear it. I can see it on some of the K-55Vs using the spectrum analyzer. I thought the way to address it was to put the worst K-55V I could find (glitch wise) in my Cornscala and use a 9 khz tone to see how well I could hear it. The test had the K-55V playing the 9 Khz tone along with the tweeter. I sat at a good listening distance and had Michael turn off the K-55 at random to see if I could tell when it was playing or not. The tweeter was so much louder (about 10 db) that I could not tell when it was on or off. The tweeter just drowned it out. If I had been able to tell it was there, I would have tried a trap. I don't know. I just have a hard time seeing it as a problem. A problem should be easy to hear.

Bob Crites

[colterphoto1]

Thanks Bob. That answered a lot, very simply. I really appreciate it.

Now about all these AL's?

Michael

[BEC]

Als are impressively heavy crossovers.

Bob

[Deang]

Since all three networks use the T2A, and all three tweeter filters come off tap 4 -- why would the B3 tweeter sound more forward? Also:

"Using a 5000 Hz first order high pass filter on a tweeter or tweeters, at 2500 Hz or one octave below the crossover frequency, power to the tweeter(s) will be reduced by 75% or 6 dB, and by 93.75 % at two octaves and so on."

"Using a 5000 Hz second order high pass filter on a tweeter or tweeters, at 2500 Hz or one octave below the crossover frequency, power to the tweeter(s) will be reduced by 93.75.% or 12 dB."

"A tweeter with a third order high pass filter with a crossover frequency of 5000 Hz driven by the 100 watt amplifier used in the power chart above, will recieve about 1.6 watts at 2500 Hz versus 25 watts with a first order filter at full output."

http://www.the12volt.com/caraudio/cross.asp#hp

If these statements are true, then acoustically the tweeter with a B3 behind it would sound less forward than the Type B.

In the B3, it appears the squakwer is brought in sooner (4uF to 5uF). It's also hard to imagine the woofer sections in these speakers sounding much alike. In my Klipschorns at least, moving from a first order to a second order low pass sounds pretty different.

Anyone ever see a K-55-V being driven with a Type B3?

[Deang]

Michael -- I recommend first order filters (Type A/Type for those who prefer low to modest listening levels. People who enjoy live levels should move to higher order filters.

[colterphoto1]

YES, Dean, that's the very gist of my question. Assuming I cannot afford your extreme slope xovers for now, would the B2 or B3 offer higher order filters than the B? I'll be using these for about 50/50 2ch listening and HT. HT at pretty high levels, stereo less so, but cranked occasionally.

If all I can do is swap out caps, or maybe add components to bring B up to B2 or B3 standards, NOW which network should I prefer in my Cornwalls?

(NOW we're getting somewhere)

Michael

[BEC]

Dean,

I don't really understand the squawker circuit of the B-3. But the tweeter is measurably getting more voltage compared to the squawker. I have posted traces of the B series crossovers before.

Bob Crites

[Al Klappenberger]

Bob,

The key to the B3 network is the 2.5 mHy inductor connected to tap 2 of the thransformer. Just multiply that inductance value by the impedance ratio at tap 2 and assume that value inductor connected from 5 to 0. Everything else is just like all the rest of the Klipsch networks. Moving the inductor down the transformer is a trick to cut cost by allowing a smaller inductor to act like a big one.

Al K.

[BEC]

Al,

I guess what I have trouble with on the B3 is trying to figure out what they accomplished with the inductor on tap 2 of the autotransformer. It does almost nothing to the squawker signal except turn it down slightly at frequencies too high to be reproduced by the squawker.

Bob

Type B3 trace.

[BEC]

Type B trace.

Bob Crites

[Deang]

Bob, I remembered those traces and pulled them up before I went to bed. At first I thought the K-77 might just being receiving more voltage in relationship to the squawker, in other words -- the squawker is just getting less. That sure isn't what your traces show! The only thing I can think of is that the 2.5mH inductor on tap 2 must be affecting the transfer of voltage on tap 4. Interesting for sure. At any rate, it is possible for the K-77 to be running a bit louder than the squawker in that network but not sound as bright or forward overall. The Type B has quite a bit more energy going to K-77 in the 4-7kHz range, where the B3 has its increase near the end.

Michael, when you think Extreme Slope think Al K. His Extreme Slope filters are truly "extreme" -- we're talking 120dB/octave slopes here. When I say "higher order" I just mean anything but first order all the way around like the Type A or Type B. I still think the stock horns really benefit from the addition of a true bandpass, but it can't be pulled off on the stock filters, especially the Cornwall where you'd have to size the low pass inductor on the bandpass for 60 ohms -- 2mH in series with the K-55. I tried it on the Type AA and there's just too much loss from all the resistance in an inductor that big. I kind of like the look of the B3, and if I was staying stock that is probably the direction I would try to go in.

Anyone catch my question about whether anyone has ever seen a K-55 running with a B3? I'm wondering because out of three stock networks for the Cornwall the B3 looks like the one best suited for high SPLs (HT and live levels).

[BS Button]

For some strange reason, I can't resist this thread. Anyway, could someone list the diaphragm sizes for the following drivers.

K51

K52

K53

K55

K57

A little birdy told me that the diaphragm in a K52 is 1.5" and the K55 is 2", making the 55 better suited down low?