Guest " " Posted August 16, 2006 Share Posted August 16, 2006 I want to remove some in-line resistors from a crossover network (see attached) and replace with at least one, maybe two autoformers (assume swamping resistors will be needed). Assume K-33, K-55, and K-77 drivers. As far as I can tell, a.) Resistor set R2 and R3 only result in a 1db drop to the K-77 driver. b.) Resistor R1 results in a 3db drop to the k-55 driver. c.) R4 and P1 probally degrades the sound some to the K-77, but does not drop the level unless the polyswitch triggers. d.) R in the K-55 circut is part of a zoble network, which selectively effects a portion of the band the k-55 covers, but does not reduce the overall level of the driver. R2=5 ohms R3=5 ohms R1=15 ohms R4 = 100 ohms, part of polyswitch functionality P1 = polyswitch R = 10 ohms, zobel network Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted August 16, 2006 Share Posted August 16, 2006 Fritz, You really haven't give us enough information to answer your question specifically. What woofer type could possibly only need a 1 dB attenuation of the K55? What crossover freq? What order? Where did that silly "Zobel" come from and what is it for? A lowpass-highpass type bandpass squawker filter is not a good idea to spite it acceptance. The high and lowpass filters of the same frequency should be paired together. You can't drop 1 dB with a transformer easily. 3 dB is pretty easy. Figuring the swamping resistor is just done like you would calculate parallel resistors. All sorts of questions on what you are doing! Al K. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted August 17, 2006 Share Posted August 17, 2006 My main goal was to remove the in-line resistors and replace with traditional autoformers. That goal includes removal of the polyswitch and associated resistor. But you rasied some intresting questions. Intresting point on the pairing of the high pass and low pass. I have noticed that approach in all of your steeper slope xovers. The PCB may be able to be re-configed to incorporate that approach. In looking at it, maybe one jumer wire and de-soldering one PCB bridge. Swamping resistor. I looked at a few combinations using on line parallel resistor calculators. I agree that the 3db drop implied for the mid-range can be easily done with any t2a type transformer. I think there is one autoformer that has 1db taps which would be able to implement the implied 1db drop indicated for the tweeter. The 1db reference is what I believe the in-line resistors in the tweeter circut is trying to accomplish. Crossover frequencies for this crossover are published as 400hz and 4500hz. I am guessing that the order of the xover is 3rd order for woofer and mid range, and 6th order for the tweeter. That is what it looks like to me. Not clear on what the zobel in the mid range is doing. I have the values for the capacitor, but not for the inductor. I'll look thru earlier versions to try to understand what the assumed needed correction is. While i only have values for the caps and resitors, I found it intresting that the additional impedance added by the in-line resistors in the mid and tweeter circut was not factored in when determining the xover componet values. It basiclly looks like the in-line resistors were and after thought. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted August 17, 2006 Share Posted August 17, 2006 Fritz, My advice is to throw out all of this and start over! 1 dB attenuation is obviously wrong. Even the Khorn woofer, as efficient as it is, still requires 3-6 dB of attenuation to the k55 to equalize their outputs! Zobel networks are just a cop-out for filter designers who don't know how to absorb the complex impedance of the driver into the filter. The K55 is a clean enough load that you don't need to do that anyhow. You often see a highpass and lowpass stuck together to form a bandpass for the squawker. Even doubly terminated filters interact when connected like that, but singly terminated ones should not have to look through another filter to see its morror-image reactance slope. Put the high and low filters having the same frequency together as two series connected diplexers. This has nothing to do with the order of complexity BTW. Al K. Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted August 17, 2006 Share Posted August 17, 2006 You also need to be specific to the types of K-77, K-55, and K-33 different versions of them had different crossover's designed around them. The K-55M needs a different network than the K-55V since it runs hotter. It seems you are trying to fix/remedy/modify an AL-4 network, best off to sell the things and start from scratch like Al suggested it will be alot easier and cost effective I would think. Keep things as simple as possible for the best results. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted August 17, 2006 Share Posted August 17, 2006 Fritz, Is that the schematic of the AL-4? I have seen and made measurements on the AK-4. The AK-4 doesn't look like that at all. Al K. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted August 17, 2006 Share Posted August 17, 2006 The diagram is different than the PCB version of the AL-4. On the PCB version of the AL-4 Woofer section, C3 is two caps in parallel Mid section, C2 is 2 caps in parallel, L2 does not exist Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted August 17, 2006 Share Posted August 17, 2006 Fritz, Just dump the AL-4 and built my Universal "ALK". Al K. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted August 17, 2006 Share Posted August 17, 2006 Al, I have a set of your universal's as well as a set of your es400+es5800, amazing peices of work. non-kit version. I want to believe there is a slight glimmer of hope to applying some easy and reasonable best practice modifications to the xovers in question. I think those in-line resistors have to go. At least that aspect should be do-able with minimal labor investment. Decoupling the band-pass by pairing of the hi-pass and lo-pass circuts looks like another piece of low hanging fruit. That in-line polyswitch/resistor combo is another toss item. Quote Link to comment Share on other sites More sharing options...
Deang Posted August 17, 2006 Share Posted August 17, 2006 Don't do it. The more elements in a filter the closer it approaches the level of rocket science. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted August 17, 2006 Share Posted August 17, 2006 FWIW I found out that the ALK Jrs. best the AK3 nets. I never heard the AL-4, but I'm just thinking that it's not worth the time and money. I even recapped my AK-3s with all Sonicaps. ALK Jrs. much better. The ALK Srs. should clean up the AL-4. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted August 17, 2006 Share Posted August 17, 2006 I have done a lot of computer analysis on the new Klipsch crossover networks and I am convinced they were designed by somebody who has no experience at all with limped component filters. They probably start with some generic network and simpy beat on it until it looked good in a anechoc chamber by adding a bunch of R-L-C networks all over the place. That's probably why the input impedance goes all over h___. There is simply no need for that. Klipsch needs to hire somebody who has actually had filter experice to do their networks. Filter design is an entirely seperate science from acoustic stuff. The two sciences could easly be blended if they would just do it! I'll bet nobody at Klipsch ever even heard of pole-placer / zero finder filter synthesis software! Let's see, one capacitor, two capacitor, three. Oh yeah, and there's an inductor over here. That's four. It must be 24 dB / octave! RIGHT! Do you hear that Klipsch? I'm available for consulting. I do it regularly. I charge $150 for the first hour and $50 / hour after that. You need me BAD! Nah.. I'm alredy doing it for K&L Microwave (the largest filter company in the world). I don't have the time! Oh yeah, K&L has 60 licenses for my PCFILT filter software. Most of K&L's engineeris use it. Klipsch: Wanna buy it? It only costs $1000 a copy. Does anybody notice I'm a bit ticked right now? Al K. Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted August 17, 2006 Share Posted August 17, 2006 uhhhhh.....i designed the crossovers........i hope that i am forgiven.......... berryboy roy Quote Link to comment Share on other sites More sharing options...
BEC Posted August 17, 2006 Share Posted August 17, 2006 Come on Al. Your turn, you've got Roy on the line. Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted August 17, 2006 Share Posted August 17, 2006 Ouch .....!!! double .. Ouch ....!!! well, Al's got Some experience, here ...[] Quote Link to comment Share on other sites More sharing options...
Deang Posted August 17, 2006 Share Posted August 17, 2006 You two need to talk -- you could learn a lot from each other. Crites and me can whip you both with two caps and a couple of coils tied behind our backs, er -- or something like that. Quote Link to comment Share on other sites More sharing options...
BEC Posted August 17, 2006 Share Posted August 17, 2006 I thought we might get to observe that talk here, but looks like Al has left the building. Dean, Have you quit answering emails again. Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted August 17, 2006 Share Posted August 17, 2006 You two need to talk -- you could learn a lot from each other. Crites and me can whip you both with two caps and a couple of coils tied behind our backs, er -- or something like that. i bet we could deangee. paul once told me when he was 95, after i told him he could teach everyone about horns, he said, "i'm still learning." i miss that guy. berryboy roy Quote Link to comment Share on other sites More sharing options...
Deang Posted August 17, 2006 Share Posted August 17, 2006 I can't imagine how bad you must miss him -- our sadness multiplied 1000 times over. Look at the bright side, he is with the Lord -- and you have us. Quote Link to comment Share on other sites More sharing options...
Deang Posted August 17, 2006 Share Posted August 17, 2006 Bob, I'm not talking to you right now, I'm still mad at you for saying that all amps that are working right sound the same. Yeah, I just saw it a bit ago. I don't know much about them -- I've never used them. Al likes them, and Craig uses them in his vintage tube amp work and VRDs. They're not yellow -- I think that's a problem. Quote Link to comment Share on other sites More sharing options...
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