Crossover components discussion

[Randy Taylor]

I found this site and thought that some of the crossover gurus, or some other people interested in crossovers might find it interesting if they have not seen it yet. They also have a forum that some might find interesting.

http://www.ellisaudio.com/CrossoverComponents.htm

[Al Klappenberger]

Guys,

That fellow talks a lot about capacitors and very little about inductors. Inductors are more important to a filter becasue they are naturally a higher loss component. THEY are the bottleneck, not the caps. He finds spiral inductors "superior" becasue he didn't try Litz wire inductors which are better yet!

Al K.

[popbumper]

Al:

Indeed! This is why I believe that cap upgrades alone, while significant to network improvement, do not address the full audio spectrum of the signal. This is why I use beter quality Madisound inductors in my K-Stack crossovers on the low end. There's just no reason to ignore the bass/midbass frequencies; if you can get gains across the entire frequency range, why not? The original crossovers were NOT built with high quality components, and caps only address PART of the problem.

Chris

[Al Klappenberger]

Chris,

Absolutely! Even the worst caps have "Q" factors of 200 but the very best inductors only measure about 50. A filter doesn't care if it's losses are in the cap or the inductor, the degradation in performace is the same. This means the inductors need to be the best you can afford and worry about the caps later!

Al K.

[Deang]

I don't agree with you guys.

Al, you model your networks from scratch with sophisticated modeling and optimization software, so you can work out all of the elements related to the parts (the loss factors, the Q of the circuits, and the reactive component between them). I still maintain that the "best" part isn't always the best part when doing rebuilds on circuits that have already been "modeled". Replacing inductors in HF circuits especially, can bring about some very nasty results. I went through several various types/brands of inductors in the HF section of my RF-7s, and each time resulted in disaster. Even though the inductance values were dead on, the higher Q of the "better" inductors brought on a treble that was overbearing and obnoxious. Circuit design also factors in the Mutual Inductance caused from the close proximity of the coils, and so changing out the coils and then moving them around causes problems too. On the LF section, it doesn't take much of a drop in DCR to screw up the alignment between the cabinet/woofer -- and I haven't seen anything that convinces me that there is any improvement to be gained from using an air core as opposed to an iron core or steel laminate.

Changing out capacitors produces good results without creating a significant shift in the sonic signature of the speaker, and I'm comfortable with that. The layman should just keep things simple, where there will be more success than failure. If you're starting with a decent recipe, you might add a little more salt, but you're not going to empty out the salt shaker. Caps make a big "enough" difference, and I STILL don't buy into all being related to insertion losses!

[Number 9]

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On 5/13/2005 6:09:37 AM Al Klappenberger wrote:

Inductors are more important to a filter becasue they are naturally a higher loss component. THEY are the bottleneck, not the caps.

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Pertaining to the Heritage line, So would you say the inductors Klipsch has been using are not great or just fine?

[Al Klappenberger]

Dean,

What you noticed change out inductors versus caps just illustrates the point I was making. Change the caps you up cut the total losses a bit. Change the inductors and you change the total loss a LOT! Why not take the losses out of the filter, allowing the filter to work at its best, then put the losses back in the form of an "L-Pad" at the output so you can control how much you want, THEN, replace the L-Pad with a transformer to get the damping factor you NEVER had becasue of all the loss!

Here's the science: Qt = sqrt (Ql * Qc). That is, the total losses is the geometric mean of all the losses in each part. The equation assumes all inductors have the same Q and all the caps have the same Q.

Al K.

[Deang]

I understand that insertion losses are higher with coils than capacitors, which is exactly why I choose not to mess with them. Now, with your example -- well sure, with something like the RF-7 that doesn't use an autoformer that would be the ideal way to handle it, but keep in mind that there is a difference between what I consider to be an "upgrade" and a redesign! RF-7 aside, I also do Forte, Forte II, Chorus, Chorus II, KLF-20, KLF-30, and the various KG's -- and they all use autoformers already. So, if I start jerking around with the inductors in the HF section, I have a major problem -- I don't have any of those speakers on hand to hear the results and make adjustments (take your Heresy dilemma for example). But it doesn't matter, I KNOW what the result will be -- substantially more treble output!

I've asked this many times, but no one will give me an answer: aren't "losses" just energy wasted in the form of heat? If so, what is the point in lowering losses just so you can add it back in with a L-pad? That one really baffles me.

What do you think about this?

http://members.aol.com/sbench102/cap.html

[Deang]

Inductors in the Heritage line: you can just about throw everything else into the mix too -- they use "standard" air cores in the tweeter circuit, and often you will see an iron core or ferrite bobbin type in the squawker section. For their type, the inductors are all decent quality.

[STL]

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On 5/13/2005 3:52:56 PM DeanG wrote:

RF-7 aside, I also do Forte, Forte II, Chorus, Chorus II, KLF-20, KLF-30, and the various KG's -- and they all use autoformers already.

Just curious, what KG-series speaker uses an autoformer?

[Deang]

A very kind and diplomatic way of telling me I'm FOS. O.K., I had a brain fart -- no autoformers in the KG's!

[sunnysal]

steve bench is quoted by many for that simple study of cap materials...I think he did a great job of showing there are differences in caps due to materials...now if he would only tackle wires we could all settle down...the closest I could find was Nelson Pass's wire study:

http://www.passlabs.com/downloads/articles/spkrcabl.pdf

tony

[popbumper]

Well, given that I designed my crossovers based a great deal on Dean's suggestions, since he disagrees with Al and I, I suppose it's a fair mathematical theorem to say that he disagrees with himself :bigsmile:].

"Kludging" caps may be a reasonable fix, but it only addresses part of the network.

On your comment, what does "For their type, the inductors are all decent quality" mean? What is decent? Have you measured the individual performances of each? Is decent based on a visual appearance or lab evaluation? That's akin to saying "a speaker sounds good" - against what reference?

Chris

[Al Klappenberger]

Dean,

The reason for lumping the losses in a pad rather then in the filter is becasue the losses not only casue a loss of total energy, they degrade the passband near the crossover frequency. The filter-tuner technicians that tune microwave filter refer to this as "D-ing off". Loss not only lower the singal coming out of the filter they actually make the passband get narrower. You see this in a very serious way in a narrow bandwidth bandpass filter but it happens in ALL filters.

Al K.

[Deang]

"Well, given that I designed my crossovers based a great deal on Dean's suggestions..."

Hmmm. Well, I certainly liked the idea of more geography so film and foils could be used, and since so many are high on air cores in the LF circuit, I thought they would be cool for that too. I'm pretty sure I was thumbs down on messing with the HF inductors (unless you could get a near match with the Janztens).

"...since he disagrees with Al and I..."

I disagree with everyone, I'm happier that way.

"I suppose it's a fair mathematical theorem to say that he disagrees with himself..."

Well, that's the way math is.

"Kludging" caps may be a reasonable fix, but it only addresses part of the network.

Kludging - (clue-geeng) - the ancient art of optimizing systems on the fly, often for non-standard tasks. Kludging requires a strong creativity quotient and is assisted by a strong familiarity with local assets (although this latter bit is not a requirement).

I appreciate the compliment Chris.

"On your comment, what does "For their type, the inductors are all decent quality" mean?

The iron cores are decent iron cores, and the standard air cores are decent standard air cores.

"What is decent?"

It means they're nicely wound, and wound tight.

"Have you measured the individual performances of each? Is decent based on a visual appearance or lab evaluation? That's akin to saying "a speaker sounds good" - against what reference?"

A coil is just a bunch of wound up magnet wire. It should be wound in such a way as to minimize the air space between the layers, and wound as tight as possible without stretching the copper. So yeah, you can tell quite a bit by looking at, and handling them.

http://forums.klipsch.com/idealbb/view.asp?topicID=47571

[Deang]

Al, your phone is ringing.

[Al Klappenberger]

Guys,

Here's a computer simulation of the AA netwrok tweeter filter with low Q parts (Ql=10, Qc=200) and high Q (Ql=50 Qc=2000). Note the passband variation are masked by losses and the losses casues the attenation to get worse as it nears the passband. This is why Litz wire inductors are better than foil inductors. Litz wire maxes out at about 6000 Hz. Foil only gets good up at 20000 where it is not needed!

Dean, This why you build the filter with qood high-Q parts and lump the level-setting losses in a pad OUTSIDE the filter. You gett a good filter that way and control of the levels too!

Al K.

Minor goof: The blue arrows on the plot show to the point of MINimum loss, not MAXimum loss..

[Deang]

I love a good picture. It's very easy to understand when you see it like that.

[popbumper]

Cool! I actually GOT a response from Dean, incredible!! I am completely amazed, after a number of ignored phone calls, emails and posts over the last two months, the most recent email sent to Dean on 4/30, reading:

>>>Hey Dean:

>>> I saw your post on the Klipsch Forum saying "contacting me" was on >>>your "to do" list. What's up?

>>>Chris

...to which I also had NO response at all. This was not the first time, it was one of many. This email was in regard to his curious statement during another thread on 4/22, where he stated:

>>>Contacting Chris is on my 'do' list this weekend. He was going to send me >>>a sample of the boards to work with, and a copy of the documentation for >>>review to get my opinion -- then he dropped out of sight.

Now, the reason Dean never received any of my documentation or boards is because, well, he would not respond. I had tried in vain on a few occasions to email and/or phone, but he refused to respond. Additionally, when I would post on his pertinent threads, I was also ignored. Why would I send something off for evaluation when I could not get any cooperation? The reason I "dropped out of site" was because I got laid off and was looking for a job. Dean HAD my phone number AND email, but would not bother to communicate. This was very surprising, to say the least, given the "support" he publicly stated early on for my project...

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2/8/05

>>>Chris, I very much enjoyed our conversation on the phone the other day.

>>>Folks, Chris has really gone the extra mile on this project, and there is >>>a very high quality product coming our way. I for one am really looking >>>foward to this.

>>>Thanks Chris!

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2/10/05

>>>Now THAT is a network. Dude, I'm drooling. That extra geography is a >>>dream come true for me. Man oh Man.

>>>Ready for this? Wrap it in some damping material, and stuff the whole >>>thing into a project box. The project box could be predrilled for the >>>speaker leads and screws that hold the beast to the back or bottom of the >>>speaker. How tall is that thing Chris?

(Incidentally, I answered, got no response)

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>>>2/22/05

>>>These PCB boards were designed by Chris for rebuilds covering most of the >>>discontinued Klipsch models. The ALK design is the property of ALK >>>Engineering, and doesn't apply here. Besides, the ALK is a substanially >>>different design than what these boards were designed to accomodate.

>>>The worst part of a rebuild for a mod is removing the old parts and >>>cleaning off the old solder and glue. Almost equally as painful is >>>dealing with the limited geography on the stock boards to accomodate the >>>new parts, which as you know are often much bigger. The option also now >>>exists to upgrade inductors if one decides too (no room at all for this >>>on the stock boards once the larger caps are dropped in).

>>>Chris has also written detailed instructions -- so now even someone with >>>zero experience can probably do it without too much trouble. A couple of >>>hours of practice with a soldering iron and some common sense, and they >>>are good to go.

>>>I'll be making certain use of the boards since I can now build up >>>networks in advance, so if one chooses, they won't have to experience a >>>week of downtime while their stock networks are shipped for modding. This >>>also means they can keep their stock networks as is. The upside here is >>>that when they decide to upgrade to a different model, they can sell with >>>the stock networks, keep the modded ones, change the values of a few >>>parts, and then use them again in their new speakers.

(All this wonderful support and encouragement, and then - ZILCH)

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On 3/8, STL popped on and asked the question (paraphrasing), "Did Dean ever get (Chris') boards and had he evaluated them yet? If not, get off his butt."

My response:

>>>The boards have not gotten to Dean yet; I never got any confirmation from >>>him on a few questions I had, and he has not inquired about these for >>>quite a while. I am working with a few folks to evaluate assembled >>>networks, stay tuned.

>>>Chris

(I would have thought Dean would have said SOMETHING here, but it was DROPPED without his response).

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Now Dean, for someone who has such a glowing reputation here, I really wonder why after all was said and done that you would not respond. There was no time EVER where I questioned your judgement, bothered you, sent bad remarks, questioned your integrity, or anything of the sort. I wanted to bring this out publicly since you WOULD NOT and WILL NOT respond privately. You will note that everything said here is taken straight from forum threads (and I would be happy to share the emails I sent you), so there is no "smoke and mirrors", or lying of any sort. I want to thank you for FINALLY responding to a post of mine - the nature of my response was obviously "strong" enough to evoke your retort, so now - come clean. I never questioned your credibility or integrity in the beginning, but you can bet that I do now. I recall you even saying during our phone conversation "I HOPE GOD BLESSES THIS EFFORT" (the crossover board project between you and I). What the HECK (were) you talking about???

Chris

[Deang]

Yikes Chris. You're making this sound worse than it is. Honestly, the last thing I remember is you saying you were going to send the stuff when it was ready for me to go over. I knew you had my mailing address, and I figured you would send it when it was ready. The stuff never showed up, and then you pretty much pulled the disappearing act.

I don't know about the phone calls, which doesn't mean I doubt you've called. The answering machine fills up pretty quick, and my daughters have a bad habit of going through and deleting messages to clear it -- assuming I've taken care of the call-backs. It's been addressed.

It's not unusual that I don't respond "in pertinent threads", because I often don't go back into every thread I post in. If I do, it's rare that I go back and read everything written since my post. I simply don't have the time for it anymore.

Most of our email correspondance was through my WPAFB work email address. This has turned into a nightmare. As part of their effort to cut down on the amount of virus' and spam coming in through email, they are now scanning headers, and what's in the header determines whether you get the mail or not. They're hitting outgoing traffic too. Trading emails with m00n recently revealed how bad it is, where we found out he gets absolutely nothing from me that goes to his Hotmail account if it has an attachment. Home is much better, but I still find stuff in my bulk/spam folder that shouldn't be going there. I did get your last response, and it's mixed in with the 10 other people I haven't responded to yet!

You know, I'm just one guy over here, and if I count the side business, I'm working three jobs. Obviously the side business suffers. No, I don't do the best I can, because doing the best I can would mean going on four hours sleep a night.

So, now that I've covered everything with lame exuses, please accept my apology. BTW, I did write your phone number down, but it's somewhere in this Black Hole we call a home. If you shoot it to me, I'll give you a call later. Well, maybe.