Crossover Roadshow

[Deang]

Al's response to the following comment by Bob:

"And, for those who like to listen to 1khz test tones, on a Khorn, I think that by the time you got to about 113db out of the Khorn midrange, you would cook the resistor."

A Khorn yields 100 dB (not the claimed 104) SPL at 1 meter for 1W input. To get 113 dB you must increase the input by 13 dB (only 9 dB if 104 db SPL at 1 meter was true). Power ratio = antiLog10 (13 / 10) = 19.95:1. Therefore, the input power must be increased to 20 watts. With the autotransformer set to 6 dB of attenuation, 5 watts goes to the driver and 15 watts goes to the resistor. The 10W resistor would get very hot but would probably survive longer than the hearing of "those who like to listen to 1khz test tones". Remember this is CONTINUOUS duty, to the midrange driver only, a situation that WILL NEVER HAPPEN with any audio program material an audiophile might listen to...

Comment from me: I asked Al how he came up with the sensitivity figure for the Klipschorn and he said he measured it. I reminded Al that Klipsch factors in room gain in their sensitivity figures. I won't repeat what he said in response to this.

[NOSValves]

I wonder why we can no longer have technical discussions on this forum without somebody getting offended. That used to be the fun part of this forum for me. Now, just does not seem worth it.

Technical discussions of this sort do not belong in a competitors road show thread.... Its blatantly obvious to me that you came in here to bring doubt to a well designed excellent performing product.

[BEC]

"Bob, honestly, over the years, it seems like every time one of these
networks is discussed you feel the need to come in and make some comment
related to the resistive element. Your first contribution to this
thread was:"

Dean,

Go back and read your thread. Mike and later Mark brought up the resistor.

[mikebse2a3]

Bob, honestly, over the years, it seems like every time one of these networks is discussed you feel the need to come in and make some comment related to the resistive element. Your first contribution to this thread was:

"Here is what Paul Klipsch had to say about impedance. He was defending the use of the autotransformer which raises impedance instead of using resistive attenuation."

I think you've posted that document in relation to this topic about a dozen times or more over the years. It doesn't always feel like it's a "technical discussion" you're looking for but simply an opportunity to undermine the performance of the design -- I believe this is what Craig was alluding to. To be honest, it just seemed out of place in this thread, but maybe not, so I responded to your concerns and criticisms just like I always do.

This is an open forum and and as I said before(about the thread between Craig and Mark which was shut down) if someone is wanting to use the Klipsch forum to sell products and Klipsch allows it (which the Crossover Roadshow is about) I'm fine with it. What I'm not fine with is anyone wanting to shut people down from discussing said products or claims. Bob or anyone has every right to post anything he believes has relevance to the matter and I don't care how many times over the years he or anyone else brings it up!

I posted earlier that there is a false assumption being made by some small wattage amplifier users that the swamping resistor makes it easier on the amplifiers and that simply isn't the case. It draws more current from the amplifier's reservoir to acomplish some impedance compensation for the network/driver. For amplifiers with plenty of power this isn't an issue but for lower power designs the reservoir can be exceeded trying to reach the same SPL's in the region where the compensation has an effect. Again whether this loss is heard by the user depends on many variables but make no mistake using the swamping resistor to bring impedance levels down did not make it easier on the low wattage amplifiers. As Dean noted there are benefits with this tradeoff for amplifiers such as single ended types exhibiting internal impedances of several ohms and will lessen the frequency variations due to these amplifiers interacting with the variation of impedances of the drivers/network's load and whether this is a good thing depends on other factors.

There are examples where this frequency variation due to impedance variations can be used to an advantage by acting as an equalizer and actually improve the performance of a loudspeaker if the loudspeaker designer fully understands his design. (Nelson Pass has shown some examples of how this works well with some fullrange speaker designs for example).

I believe it's safe to say PWK new his designs very well and knew the pros and cons of impedance variations! As Bob posted (PWK's Paper)there can be advantages with impedance variations if one knows how those variations will effect the acoustical output of the loudspeaker and isn't a design flaw if used properly!

I do agree that if one is using a passive network and wants to experiment with different drivers or midrange levels the swamping resistor makes that reasonably possible.

miketn

[Deang]

Mike was challenging the idea that a constant impedance crossover presents an easier load for SET amplifiers.

You challenge the idea that the use of a resistor(s) can make a crossover better and improve the performance of a loudspeaker -- big difference.

Here is what Mike said:

"The idea that the constant impedance networks makes it an easier load for low power set amps or any amplifier versus the older Klipsch networks seems to be a common misconception on this forum. To bring down the rising impedances of a network means you have to parallel a lower impedance element or elements to the network for compensation. This increases the current demand from the amplifier and without question makes it work harder. The only benefit is as you stated is the less frequency variation due to impedance interaction between amplifier and network/loudspeaker."

I always find it interesting how people like to take valuable performance attributes or feature set(s) and trivialize them if they contribute to a weakening of their argument. For example:

"The only benefit is as you stated is the less frequency variation due to impedance interaction between amplifier and network/loudspeaker."

"I just say, why does anyone want the impedance to stay the same all across the three (or two) drivers in a speaker. What exactly do we gain from that, (leaving out the ability to adjust outputs easily for a moment)?"

So, I guess a reduction in the variation of the frequency response, presenting a stable and consistent load to an amplifier, and the ability to easily adjust the output level of the midrange driver with minimal impact on the crossover point while providing very low summing error -- are all what exactly? Insignificant, undesirable, unimportant?

[mikebse2a3]

Technical discussions of this sort do not belong in a competitors road show thread....

Maybe if that's your attitude all threads meant to help sell products to Klipsch forum members need to be taken off the forum...?

[Deang]

Hi Mike,

If you missed Mark Deneen's comments regarding your assertions and conclusions about the amplifier "working harder", you might want to go back and read what he said. Still, I understand where you're coming from, and for the most part don't have a problem with it.

I emailed Amy before I opened this topic. I started this thread to help me figure out if something I used to build and sell for $750.00 could be scaled down and sold for $350.00. The idea was simple: give people an opportunity to hear something different in exchange for feedback. Another purpose of the thread was so users could share/trade notes about their experiences (since several are using different horns and drivers). I was naturally curious about how the crossover would do when compared to the various Klipsch designs. I mean, I had my own opinions, but I wanted to know what others thought. Now, I did inform everyone that they were not obligated in any way to leave comments regarding their experiences in the thread, and that they could email them to me, and many have -- they could do whatever they wanted, even post negative comments. To be completely honest, I thought the responses would be more even handed and I really didn't expect such an overwhelmingly positive reception. BTW, If I wanted to openly promote my work on this forum you would see something quite different.

I did another Roadshow about a decade ago. I think Mark sent some JMA units out to Beta Testers back in the day. Al sent ESNs and Trachorns out, and Greg did one for the V-trac. When you do a thing like this, you aren't thinking so much about the promotional aspect as you are about the fact that you're stressed about a decision you're about to make on a product and you want to know what people think. Most have done something like this in the past and as far as I know it's never been a problem.

There has always been what we will call an unspoken rule, but in reality, it's been discussed off forum -- which is why the crossover guys have generally been pretty well behaved: We are supposed to respect each other's space. I don't share my thoughts about Bob's tweeters in his tweeter threads (don't even do it when it's a forum member), go in and make comments about his crossovers in threads dealing with his crossovers (unless I feel like I can help), or dive into any of the other gazillion threads dealing with the things he sells (diaphragms, horns, drivers and loudspeakers). Now, I don't want to hear any nonsense about how none of that counts since Bob usually doesn't start those threads -- because they still concern his products, and as a competitor, I could easily go into any of them and do anything from muddy the waters to outright sabotage. I don't do it and everyone here knows it. I'm vocal about my dislike for the Sonicap, but that's about it -- but you won't see me doing it in his threads, I do it in mine.

The topic at hand has been discussed ad nauseum for years. I didn't have an issue with you bringing it up in the context you did because it made sense to do so and was perfectly acceptable. However, I have no choice but to question Bob's motive, especially as it pertains to this particular topic. Craig is right, Bob could have posted a new topic in the correct section of the forum instead of disrupting this one. As a matter of fact, you even had the courtesy to bow out when you realized you were hijacking the thing. I don't understand why you recognized this at the time as it relates to you but don't see how it's applicable to Bob.

I apologize to those who simply see this thread as a form of self-promotion. It was really just more convenient to do it this way. I'm tired and have a lot on my plate. This thread saved me from having to deal with a multitude of email, Facebook posts, and more work on my website -- none of which I have time to deal with right now.

[BEC]

"I do agree that if one is using a passive network and wants to
experiment with different ........ midrange levels the swamping
resistor makes that reasonably possible."

Mike, that is where I was hoping to take this discussion to get a few opinions on that. We also know PWKs opinion on that. The resistor dissipation thing blew up and turned ugly before I could get there. I tried to get that going by mentioning that some have wanted to do that when the real problem was woofer phase. Other times it is when the Khorns are not sealed good into the corners.

[Deang]

"I do agree that if one is using a passive network and wants to experiment with different ........ midrange levels the swamping resistor makes that reasonably possible."

Mike, that is where I was hoping to take this discussion to get a few opinions on that. We also know PWKs opinion on that. The resistor dissipation thing blew up and turned ugly before I could get there. I tried to get that going by mentioning that some have wanted to do that when the real problem was woofer phase. Other times it is when the Khorns are not sealed good into the corners.

You're being disingenuous. You were asking me directly, not looking for opinions. After I answered your question you could have got to the point straight off. PWK was a really smart guy who didn't think anyone was competent enough to do anything with his loudspeakers, so what do you think he would think about what you're doing?

Dee Edwards runs his system with the squawker on tap 3 and has for years. I've lost count of the number of people I've done that mod for. It's just a simple fact that many think the midrange is too damn hot, and besides, your solution does absolutely nothing for those who are dumping the stock top sections. It's certainly something that should be checked but it has very little bearing on whether someone prefers this network over another.

Dead or broken link Mark. Thanks for the words.

[Deang]

Bob, let's sum up:

Bob: Here is what Paul Klipsch had to say about impedance. He was defending the use of the autotransformer which raises impedance instead of using resistive attenuation.

Dean: Okay Bob, with respect, using the resistive pad, TIM is -76dB down, and we should be worried about this why exactly? Besides, I thought it was your position that this type of low level distortion is swamped by other, higher level forms of distortion (diaphragm, etc.).

Bob: That was PWK, not me. You know he was all about low distortion even to the expense of everything else. I just say, why does anyone want the impedance to stay the same all across the three (or two) drivers in a speaker. What exactly do we gain from that, (leaving out the ability to adjust outputs easily for a moment)?

Bruce: I think it makes it easier to predict a more accurate response of the system. Especially with tube amps. I'm not at all sure about SS amps. With tubes, the transformer will relfect the varying impedance back into the plates...

Bob: But that was the kind of amp PWK would have been using when he made the case for using autotransformers and letting the impedance rise.

Dean: That DFH deals with one type of distortion, but there are many types and we should be concerned with all of them...

I then quote Dennis, and reproduce his plots from Olson. I also point out that the amp used for the DFH you posted was not a tube amp but the BGW100 (solid state)

DJK quote: Adding the swamping resistor cannot alter the acoustic loading the driver sees (which causes the distortion to peak when the impedance peaks too), but it does allow the crossover to work much better."

After providing a detailed response which included quotes from DJK and associated plots, you again ask:

Bob: ...How do we have less distortion?

Bob: ... Let's remember that the swamping resistor is going to take away about 3db of amplifier output. You have to consider that PWK said that more power drawn out of an amp equaled more distortion.

Dean: Those questions have already been addressed. I think you falling back on this amplifier distortion thing is pretty funny considering some of the things you've said about that in the past. This is a crossover thread, I'm more concerned with the distortion emanating from the network and the drivers/horn. If you're right about all of this stuff, then everything you guys build should sound better than what I build, but that's not what's happening is it -- and we don't have people running around screaming about how they're running out of amplifier power. I've got customers using these networks with 1.5wpc amplifiers, where are the complaints?

Bob: I guess this means that if you had a horn mouth reflection that occurs at the crossover point, you might see changes in the slope. And that the swamping resistor would damp them. Do we have any of those?

At this point I defer to Dennis who never shows up. I dig off and on in my spare time and draft the post that can be found on page 9 which includes outside sources which substantiate what Dennis has always said.

Finally, on page 10, you say:

Bob: I wonder how many of those who "fixed" the sound by turning down the midrange really had a phase reversal on the woofers. I know that several I have talked to who initallly wanted to know how to lower the midrange output, got happy with the factory balance once they got the woofers in phase.

John Warren then posts the links to his plots which show the sky is falling.

Deneen: The load on this resistor is spurious. It is not anything like using it in a DC circuit in which the current cycle is 100%. This resistor is going to see a fractional duty cycle of a series of millisecond peaks. It takes "seconds" of applied current to heat a large resistor.

Bob: I was able to get Al's swamping resistor pretty hot during a test I did for him and Dave using the Eliptrax horn and HF200 driver crossed at 400hz to see if the combination worked good enough to use in a Khorn. I used about 100 watts into the crossover for about an hour... And, for those who like to listen to 1khz test tones, on a Khorn, I think that by the time you got to about 113db out of the Khorn midrange, you would cook the resistor.

Then we end up here with you quoting Mike's statement, "I do agree that if one is using a passive network and wants to experiment with different drivers or midrange levels the swamping resistor makes that reasonably possible."

Bob: Mike, that is where I was hoping to take this discussion to get a few opinions on that.

So Bob, now that have most of the thread history involving you here before us -- at what point exactly were you planning on getting to that?

I believe we have adequately dealt with the objections.

1) People are not losing half of their amplifier power. Study Al's plots. Forget the plots, use practical experience and common sense.

2) Swamping a network back to 8 ohms presents a resistive load (as opposed to reactive one), and replicates a constant load similar to which amplifiers are designed to work with. [EDIT: see Mdeneen's post at the bottom of the page]

3) The resistor only gets hot if you're playing big band music 78 rpm records or 1kHz test tones at 100wpc.

4) The resistor is a 10 watt resistor, and since it only gets hot and doesn't burn your house down -- it's highly unlikely that it's drawing 10 watts, again, study the plots.

5) The resistor works in conjunction with the autoformer to attenuate the output of a driver with higher efficiency. It's drawing off power that's not being used anyway.

6) The crossover provides a useful and in my opinion, necessary feature. You can adjust for personal taste, room issues (no carpet, drapes, etc.) and cab used to account for the effects of changing horns and/or drivers.

This is what I see:

"Here is what Paul Klipsch had to say..."

"That was PWK, not me..."

"But that was the kind of amp PWK..."

"You have to consider that PWK..."

Dave Harris just asked me if our learning curve stops after reading something PWK said 40 years ago.

Al wants to know if PWK is God and the final authority on all things audio related. He also said this, which I think is worth sharing:

"...He was a pioneer, not GOD! Henry Ford was a pioneer too and he told everyone the model "T" was the right car for everybody and there is no need for new model. He kept saying that up until Cheveroet started running him out of business and his dealships started to complain."

Having a relationship with Max meant you had to keep your mouth shut, he often shared things he knew he shouldn't. If you didn't open your mouth, the stuff got better and better, making it harder and harder to not say anything! Max is gone now, and I just asked Al what he thought about letting some things go -- so here is one that you're not going to like:

At the time, autoformers were relatively inexpensive and widely available. Large capacitor values were expensive and not easy to get in high quanities. According to Max, the choice of using an autoformer was largely a business decision driven by cost: "Allowing the autotransformer to raise the impedance allowed for smaller capacitor values which reduced his production costs, and it was the only reason."

Based on the stories we have on some other things related to cost, this one is not hard to believe.

We hear a lot about the upside of using an autotransformer, but not much about the downsides, as if we are to believe there is none. It's so much easier and interesting to ***** about a resistor.

Edited April 5, 2014 by DeanG

[BEC]

"I do agree that if one is using a passive network and wants to experiment with different ........ midrange levels the swamping resistor makes that reasonably possible."

Mike, that is where I was hoping to take this discussion to get a few opinions on that. We also know PWKs opinion on that. The resistor dissipation thing blew up and turned ugly before I could get there. I tried to get that going by mentioning that some have wanted to do that when the real problem was woofer phase. Other times it is when the Khorns are not sealed good into the corners.

You're being disingenuous. You were asking me directly, not looking for opinions. After I answered your question you could have got to the point straight off. PWK was a really smart guy who didn't think anyone was competent enough to do anything with his loudspeakers, so what do you think he would think about what you're doing?

Dee Edwards runs his system with the squawker on tap 3 and has for years. I've lost count of the number of people I've done that mod for. It's just a simple fact that many think the midrange is too *** hot -- and besides, your solution does absolutely nothing for those who are dumping the stock top sections. I do however agree that it's something that should be checked, but it has very little bearing on whether someone prefers this network over others -- there's more responsible for the sound than .8 additional attenuation (the way I ship them).

Dead or broken link Mark. Thanks for the words.

OK, Dean, believe whatever you want. You sure have turned into a
grumpy old man lately. I have never said anything bad about your
products either here or anywhere else on the internet. I don't even
criticize your products when a customer asks me why he should buy mine
or yours or ALKs, and that happens almost every day. You do criticize
my products both here and on other places on the internet and most
certainly directly to customers because they have told me that.

But, let's
get one thing straight. You are selling on the Klipsch forum. You
changed your identity to your company name, you post links to your
website on every post you make. Both you and Craig have done that. Why
do that unless you wanted free advertising on the Klipsch website to
help generate sales?

And, by the way, your selling here does not
bother me at all. I guess that is open now for any members who want to
sell here unless you are somehow special.

Anyway, on the
attenuation by user, (and I have said this to you many times) I would
prefer that the speaker remain as PWK would say "an accurate
RE-producer". There are other places in the chain that you can tailor
the sound to your taste if your taste varies from that you hear from an
accurate reproducer. That is why they made tone controls and
equalizers.

[Deang]

"OK, Dean, believe whatever you want. You sure have turned into a grumpy old man lately."

Here we go with the "grumpy" thing again. More like ticked off, how's that? It started when you changed your signature designed to insult half the people on the forum but was obviously targeted at me because you changed it right after one of our capacitor exchanges. I was offended but just let it go. More recently, Michael jumped on my business Facebook page and said that no one should be building crossovers unless they build 700 a year or some nonsense like that. After the exchange with him, I called you thinking I might get an apology for his rude behavior, but all I got was excuses.

"I have never said anything bad about your products either here or anywhere else on the internet."

So verbally criticizing networks that use swamping resistors or paper in oil capacitors ("audiophile garbage") doesn't count?

"You do criticize my products both here and on other places on the internet and most certainly directly to customers because they have told me that."

I criticize your approach to building crossovers. I don't tell them anything different than you already know I'm telling them! We've agreed to disagree on that issue. I believe the original networks contained losses that should be replicated in the rebuilds. Your high pass sections are too hot, always have been. So, do they also tell you the things I say as they relate to you as a person? I'm sure there's some people reading this thread who I've talked to on the phone about you -- I invite them to share.

"But, let's get one thing straight. You are selling on the Klipsch forum."

Wow, and you're not? You've had so many parts cloned I'm surprised Klipsch still has a parts department, and half of everyone around here pushes everything you sell -- you've got your own built in sales department here. Am I really supposed to take your accusation seriously?

"You changed your identity to your company name, you post links to your website on every post you make. Both you and Craig have done that. Why do that unless you wanted free advertising on the Klipsch website to help generate sales?"

I asked Amy to do that for me so everyone would know I was a vendor, per forum rules. Yes, I'm advertising my Facebook page so I can answer questions for people about my products (can't really do it here, can I?), and the link to my website reduces my email traffic and phone calls. Do you really believe no one here knows I build crossovers as a side business -- what do I need free advertising for?

"And, by the way, your selling here does not bother me at all. I guess that is open now for any members who want to sell here unless you are somehow special."

I don't sell loudspeakers or anything else that makes me a direct competitor to Klipsch.

"Anyway, on the attenuation by user, (and I have said this to you many times) I would prefer that the speaker remain as PWK would say "an accurate RE-producer". There are other places in the chain that you can tailor the sound to your taste if your taste varies from that you hear from an accurate reproducer. That is why they made tone controls and equalizers."

With the stock components, there are really only three settings that I recommend. I ship them attenuated at -3.8dB, most leave it there. Didn't you tell me that the AK-2 crossover has a squawker that's -6dB? Who decides what is right?

I don't think you're going to get anyone here to agree that the Super AA is not an accurate reproducer of sound.

Edited April 5, 2014 by DeanG

[BEC]

And one more thing. The reason, for checking the resistor to see how hot it got was because of this statement back during that testing. This is what ALK wrote to me in an email on Feb 4, 2011 after I told him I woud be testing the speaker at about 100 watts input to see if the HF200 driver could stand it.

ALK "Be a bit careful if you run sustained high power above the crossover using my AP12 network. That 10 Ohm resistor across the transform might get too hot. It wasn't intended for PA use!"

[Deang]

I guess you were using the AP12 in a two-way situation? Was it even designed for that purpose? I ask because he says, "above the crossover" ...

Was it too hot to touch, could you leave your fingers on it?

[BEC]

I guess you were using the AP12 in a two-way situation? Was it even designed for that purpose? I ask because he says, "above the crossover" ...

Was it too hot to touch, could you leave your fingers on it?

Al, sent it to me to see if that crossover would work for a 2-way Klipschorn. That is the test we were doing...To see if the HF200 driver and Eliptrax horn would work as the HF section in a Khorn. And could the HF200 driver stand high power crossed that low. Pretty successful test. His resistor got hot, but not "too hot' in my opinion and the driver lived through the test.

[BEC]

"Here we go with the "grumpy" thing again. More like ticked off, how's
that? It started when you changed your signature designed to insult half
the people on the forum but was obviously targeted at me because you
changed it right after one of our capacitor exchanges."

Hate to burst your bubble on this, you should have asked me. No, that was aimed at another long term forum member. Did not even have anything to do with capacitors at the time I wrote that.

[BEC]

"More recently, Michael jumped on my business Facebook page and said that
no one should be building crossovers unless they build 700 a year or
some nonsense like that. After the exchange with him, I called you
thinking I might get an apology for his rude behavior, but all I got was
excuses."

And you know from the phone call at the time that Michael thought he was joking around with a friend. He did not know that you had become "grumpy" since he last talked to you. Why did you stop on your comment before mentioning that you then censored his post. Does ALK know that you do that? He has posted on his website that your facebook page is a place he can go to post anything he wants without censorship? You need to tell him that only applies if you like the post.

[BEC]

"I criticize your approach to building crossovers. I don't tell them
anything different than you already know I'm telling them! We've agreed
to disagree on that issue. I believe the original networks contained
losses that should be replicated in the rebuilds. Your high pass
sections are too hot, always have been."

We may have agreed to disagree, but you are still wrong. My best reference is from PWK, but I know you don't like to see him brought up in the Klipsch forum. Also, the fact that I bought lots of Klipsch speakers and ran curves on them to verify they were indeed "balanced" with the new crossovers.

[Deang]

Well yeah. I deleted his post because I took it as a shot at my competency. There was nothing in the post indicating he was kidding around. That page is visible to a lot of people and it had no technical merit, so I deleted it - it's the only post I've ever deleted. Al has a few things on there that grate my nerves -- they're still there. The page is there for discussion/exchange of information, and wasn't put up so my competitors could take cheap shots at me. Quit confusing grumpy with fed up. I didn't know he was kidding until I called you, and in case you didn't know this, it's customary to offer an apology with misunderstandings. You were just flippant about it, which didn't do much for old grumpy.

[BEC]

Well yeah. I deleted his post because I took it as a shot at my competency. There was nothing in the post indicating he was kidding around. That page is visible to a lot of people and it had no technical merit, so I deleted it - it's the only post I've ever deleted. Al has a few things on there that grate my nerves -- they're still there. The page is there for discussion and the exchange of information, and wasn't put up so my competitors could take cheap shots at me. Quit confusing grumpy with fed up. I didn't know he was kidding until I called you, and in case you didn't know this, it's customary to offer an apology with misunderstandings. You were just flippant about it, which didn't do much for old grumpy.

Yes, I relayed your apology to him and he accepted it. Are you now saying you are retracting the apology and instead want one from him?

I don't remember it word for word, I did read it and had a laugh about it. I told him you would be right back at him. Instead, the editing was done. That made him grumpy.