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Last Belle Crossover ?


seti

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It's the AB-3. No published schematic. However, since it's discontinued they might give it to us if we ask. Who wants to ask?

Who do I ask ? Should I just call the tech line?

Thanks for the info and older schematics. I have an AA that Bob Crites upgraded the caps for me and made convertable to A. I will keep these installed on one side of the cabinets but I was curious what was the last xover from klipsch so I could put that on the other side. This way I could have original and the latest xovers in the same cab.

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Hey seti

You might already know this but the different networks were also used with different drivers and even the tweeter is flush mounted in later years so to hear how each is supposed to sound you will need the correct drivers and even the mounting position of the tweeter if that is your purpose in using the different networks.

mike tn[:)]

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Hey seti

You might already know this but the different networks were also used with different drivers and even the tweeter is flush mounted in later years so to hear how each is supposed to sound you will need the correct drivers and even the mounting position of the tweeter if that is your purpose in using the different networks.

mike tn[:)]

No I didn't. I assumed they used the same eminence drivers or drivers with the same specs. The Belles I have are from 1980. They sound great right now so I don't plan on replacing that many parts. I thought it would be cool to have the most modern crossovers in addition to the A/AA.

Thanks

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seti

There are pro's and con's to moving to later versions of the xovers.

In general, the earlier xovers were gentle slooping xovers, and the later are more steeper in parts of their layouts.

The steeper sloping xovers provide better imaging and clearer detail, especially at moderate to high power levels.

The gentle sloping xovers have a greater appeal at lower power levels due to the wide coverage of each driver which has a greater area overlap. One of the issues of a gentle sloping xover is the chance of distortion or driver damage at higher power levels due to the wider range the drivers cover.

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Hey seti

You might already know this but the different networks were also used with different drivers and even the tweeter is flush mounted in later years so to hear how each is supposed to sound you will need the correct drivers and even the mounting position of the tweeter if that is your purpose in using the different networks.

mike tn[:)]

No I didn't. I assumed they used the same eminence drivers or drivers with the same specs. The Belles I have are from 1980. They sound great right now so I don't plan on replacing that many parts. I thought it would be cool to have the most modern crossovers in addition to the A/AA.

Thanks

seti,

The driver sets are all close enough that you can use any of the crossovers. See this thread for driver test comparisons on the different midrange drivers.

http://forums.klipsch.com/forums/thread/772921.aspx

Bob Crites

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mikebse2a3 is absolutely correct. Because of different designs, efficiencies, etc. of the various drivers--tweeter, squawker, and woofer--they aren't interchangeable, yet almost everyone on this forum treats them as if they were. For example, everything else being equal, a K-77-M tweeter paired with a K-55-V squawker sounds much too bright and harsh when fed by an"AA" or "A" crossover. Similarly, a K-55-M squawker overpowers a K-77 Alnico tweeter on the same crossovers.

What's more to the point, crossovers--both stock and aftermarket--are designed or upgraded in order to achieve sonic balance with a particular combination of woofers, squawkers, and tweeters. Changing one of the elements of that combination for a driver of different efficiency will upset the sonic balance that the crossover was originally designed to achieve; a crossover is, after all, called "a balancing network." About the only real way to get the sonic balance an upgraded or aftermarket crossover was designed for is to keep (or install) the exact drivers the designer or upgrader used to design or upgrade the crossovers, and, in order to do that, you have to know what the designer used for his tests or, in the case of Al Klappenberger's adjustable crossovers, simply not mix Alnico and ceramic magnet drivers.

I suspect that some of the dissatisfaction with the K-77 and K-77-M tweeters may simply be that they are connected to a crossover that was not designed for them.

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"For example, everything else being equal, a K-77-M tweeter paired with a K-55-V squawker sounds much too bright and harsh when fed by an"AA" or "A" crossover. "

This is completely untrue. The Type AA was used with K-55-Vs and K-77-Ms from the time the K-77-M was adopted, primarily the early '80s.

I and others have measured some of my K-77s and K-77-Ms and cannot see any real difference in the graphs. If anything, the K-77 I tested is hotter than my K-77-Ms.

I DO find Type A designs with modern caps faintly bright. This is because the K-77-series of tweeters are really rated at 105 dB/w/m and the low loss caps let it all shine through.

The K-55-M appears to be about 1 dB louder than a K-55-V. This would be heard as a "flavor" and might be quite unwelcome in a live room. The Most Horrible Type AL network has enough components in the squawker circuit to bleed off that dB or so, bringing the -M back into balance. A Type A or AA network might not sound so nice with a K-55-M. however, I find my ALK networks sound nearly identical, at least in frequency balance, whether a -V or -M is installed.

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John--

The results of your tests are surprising and completely opposite to my tests and experiences, those of other posters on this forum, and statements in "The Dope From Hope" that the K-77-M is 2-3 dB louder than the K-77 Alnico. I'm a little confused about how many K-77's you tested, since you say both "some of my K-77s" and "the K-77 I tested." Every one of the nine K-77-M's I have is from 3-5 dB hotter than every one of the six Alnico K-77's I have, so the K-77-M's that I have are consistently more efficient than the K-77 Alnico's. OK, I accept that your K-77-M's aren't louder than your K-77 Alnico('s); mine--and those that belong to other posters--are.

Although I can't seem to find the URL for his posting, Al Klappenberger a year or so ago posted a graph that showed the K-77-M to be at least 3 dB hotter than the K-77 Alnico.

As far as I am aware, all the posters who have changed the tweeter autoformer taps on their Heresy crossovers because of self-described harshness and who have been happy with the resulting tweeter attenuation have had K-77-M tweeters.

Also, your statement that the K-55-M is only 1 dB louder than the K-55-V is also contrary to the measurements and statements of other members of this forum and the Klipsch engineers. Again, I won't disagree that your K-55-M's aren't more than 1 dB louder than your K-55-V's; my K-55-M's--and those that belong to other posters--are.

Even if we assume for the sake of argument that every K-77 Alnico may actually play louder than the K-77-M or that every K-55-M is only 1 dB louder than the K-55-V, it still makes the point that the various tweeters and midrange drivers have different efficiencies and need to be matched based on their efficiencies, or sonic imbalance will result.

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First what I was wanting to make sure of was that seti knew that there was different network/driver combinations and the way I read his post was that he thought he would just be comparing networks from various years which wouldn't be happening if the drivers not orginally used when a given network was developed and voiced weren't used also. I have no problem with anyone trying different driver/network combinations but if you want to hear it the way Klipsch made it sound you should use the crossover/driver combinations that Klipsch used.

As far as the various drivers go there are small differences in efficiency of maybe about 1db to 2db and there overall frequency trends do vary. Since they operate in an area were our hearing is most sensitive chances are you might perceive slight differences in sound between them and a person might easily like one over the other just because of how that 1db to 2db difference although subtle at first can in the long run make a difference to you.

One other thing people might not be aware of is that the (I'm not sure with the AK) AK-2 and AK-3 networks (which were designed with the K55M Squawker and the K77M Tweeter) Tweeter was also moved to be flush with the front of the baffle with Z brackets). So in a Khorn with The AK-2 and AK-3 networks and Flush Mounted K77M if you subsitute the K55V in it's place you will have a narrow cancellation notch at about 6k Hz if I remember correctly due to a time difference between drivers. How audible that would be is open to debate but it is there.

mike tn[:)]

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.....

"For example, everything else being equal, a K-77-M tweeter paired with a K-55-V squawker sounds much too bright and harsh when fed by an"AA" or "A" crossover. "

This is completely untrue. The Type AA was used with K-55-Vs and K-77-Ms from the time the K-77-M was adopted, primarily the early '80s. " .......

I am going to back up John on this point. I have 1982 K-Horns (stock) with an AA network (caps were recently refreshed). The configuration was, as John pointed out, a K-77M tweeter with a K-55V (soldered terminals & fancier phase plug) midrange.

The unit does not sound too bright (even with the fresh caps). I believe the the differences in sensitivity between the two teweeters mentioned is only about 1 or 2 dB. If they differ by only 1 dB the difference in output would not be very audible.

Good Luck,

-Tom

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Tom--

That's fine, I really can't argue that you can't hear the difference between a K-77 Alnico tweeter and a K-77-M on your system--and I sincerely believe that you can't--any more than you can argue that I can't hear and measure the differences between them on my system. Many other people, including Klipsch, can hear and measure the difference as well.

Furthermore, I realize that it isn't reasonable to say that, given manufactoring and material tolerances and individual driver incidents and accidents and the vagaries of every system, EVERY K-77-M is louder than EVERY Alnico K-77 by a certain amount, but they were made to be and the vast majority are. Consequently, it's correct to make a statement to that effect in general terms without taking into account the few exceptions. The same is true for the K-55-V and the K-55-M. In other words, while it may not be true IN EVERY CASE, that's certainly the way to bet.

Nevertheless, Tom, you are still helping to make my point. Please note that my point isn't simply about the relativeness loudnesses of the Alnico K-77 vs the K-77-M; it's about the relative loudnesses of those tweeters when paired with squawkers of different efficiencies.

Again, for the sake of this discussion, even if the Alnico K-77 were only a 1 or 2 dB softer than the K-77-M as you maintain, when the Alnico K-77 is paired with a K-55-M midrange--which is, according to Klipsch and the measurements of others on this forum and my own experience, about 2 to 3 dB more efficient than the K-55-V--the Alnico K-77 would be from 3 to 5 dB softer than the K-55-M and will get lost. The same but opposite effect can happen when the Alnico K-77 and K-55-M are paired. The differencies in efficiencies are additive and matter most in reference to the other driver and, consequently, are greater than either driver individually.

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I am not sure where the hostility is coming from.

The pairing of the K77M and the K55V with an AA network was a somewhat standard configuration in the early 80s. That was simply my point.

It is not an oddball configuration, in fact Klipsch thought it was okay. If there is a problem with this combination, then a couple of resistors (or a different tap on the transformer) could solve the problem.

-Tom

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