Crossover Roadshow

[Marvel]

Bob,

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, probably creating all sorts of havoc, in the same way changing the taps on the autoformer.

Dean -- I sent an email but hadn't heard back. Billy is really, really busy right now and says he can drop down farther on the list. Who should these go to next?

Bruce

[thebes]

It always makes me laugh when people are open to the fact that capacitors can make a difference in sound but cables can't have an influence.

I understand, and know that there can be an influence. However, my wallet isn't too fat, so I can't even begin to go down that road. Have you ever talked to anyone at Klipsch about all the esoteric cables they use?

Bruce

Who said cables have to cost alot to have an influence? Not I...!

Klipsch doesn't use expensive capacitors either does that mean they don't have an influence? Does an increasing cost of a capacitor always correspond to an improvement in sound? Cost isn't a good or complete indicator of performance in any product or given situation.

Edit: I have found that construction and materials can to some degree be used as an indicater of a good cable in my experience based on my listening experiences.

Have you ever talked to anyone at Klipsch about all the esoteric cables they use?

No need Marvel....I've done my own research and came to my own conclusions and implemented what I've learned into my system.

miketn

Edit: I sure hope my equating capacitors and cables having potential audible influences doesn't wake up the mighty Thebes...I see he is lurking on the forum this morning.!

OFFICIAL FORUM REFEREE CAUTION! CAUTION! CAUTION!

Cables and capacitors are not ever, and I mean, ever, to be used in the same sentence. Any implication that an rca cable built outside of the construction specification for skinning etc. can beneficially benefit the sound of music must be immediately labelled by any Forum member in good standing as "balderdash!"

However, references to oxygen free copper" will be allowed, because copper is copper and if you like your copper without oxygen, it certainly won't affect the taste. Quite frankly, oxygen free copper is too brittle in taste, doesn't really go with any dish, not even fish, and gives wine a bitter and metallic aftertaste.

OFFICIAL FORUM MODERATOR OUT

[BEC]

Bob,

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, probably creating all sorts of havoc, in the same way changing the taps on the autoformer.

Bruce

Bruce,

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.

[NOSValves]

He'll no, blame that thread. Just finished them last night. I almost shipped after work today, but then remembered they would just spend the weekend in a 100+ degree UPS truck.

What thread would that be....UPS you really use UPS?

[NOSValves]

I prefer not to have the tonal shifts, thanks. It's one less thing to juggle. Unless I'm going to buy snake oil cables to shift it back.

Thanks for the morning chuckle!

[Budman]

i got these from Dean yesterday for my cornwalls. can't wait to put these in.

picked up a pair of belles last week. gonna be hard to decide what to put in them

[Deang]

"That was PWK, not me. You know he was all about low distortion even to the expense of everything else..."

Yes, I know who said it, but you posted it to show the evils of using resistors. That DFH deals with one type of distortion, but there are many types and we should be concerned with all of them. We were on the phone once talking about low level noise from capacitors. I was taking the position that distortion is accumulative and that certain types of low level distortion are audible. You said that even if it existed, which you doubted, that it would be swamped by distortion from the driver. I finally agreed with you, but after I hung up I soon changed my mind. You might remember that I was in Target picking up some things while we were talking. I wasn't feeling all that well and the noise was really getting to me. You remarked that it didn't sound that bad on your end. I was surprised because it was bad enough that I could barely think. You asked if I was using an iPhone5 and I said yes. You explained to me that Apple had a circuit in that thing to deal with background noise, which explained why you couldn't hear the chaos. I was thinking about that circuit after we hung up and something dawned on me: If I could remove or dial down all of the voices and noise coming from the other end of the store (lower level noise) -- would I notice it? What if I been using a phone without that circuit, would the loudness of my voice "swamp" the noise in the background, or would it have caused you to strain to hear what I was saying?

"...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)?"

Dennis (DJK) has covered this ad nauseum over the years. He has a lot of posts about this here and on other forums. Does anyone here believe that when it comes to horns and drivers that Dennis doesn't know what he's talking about? I only call Dennis twice a year because we end up talking for hours, our last conversation lasted seven hours, it's exhausting and it takes me a week to digest a tenth of what he throws at me. Max Potter was the same way -- brilliant guys. Trust me, please trust me on this -- the guy knows what he's talking about.

"The crossover does not work properly unless loaded by its design impedance. Horns have large impedance peaks near their low frequency cut-off. A swamping resistor reduces these peaks. The capacitor value needs to be increased to keep the crossover point the same." -- DJK

"All horns with small mouths have impedance peaks near their cut-off points. These cause peaks in the response as well. Swamping these peaks with a resistor will tame a lot of these response peaks. The value change on the capacitor keeps the crossover frequency the same." -- DJK

Back in 2006, I said to Dennis, "I get the impression the impedance issues are acoustic related, and are caused by reflections in the horn throat and mouth -- and it's difficult for me to grasp how adjustments in the filter squelch the peaks."

"They are caused by mouth reflections. Perhaps these figures will help:

http://forums.klipsch.com/idealbb/files/Olson%201.gif

http://forums.klipsch.com/idealbb/files/Olson%202.gif

You can tell how much the design cheats by looking at the magniture and spacing of the impedance peaks.

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."

So, what do we gain with the swamping resistor? Less distortion.

"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."

It was the mid seventies. They were dealing with the issue of why many solid state amplifiers sounded so bad. Matt Otala discovered TIM or slewing distortion and it related to transistor amplifiers. The amplifier that was used for testing in that particular DFH document was the BGW100. Otala's principles live on with Electrocompaniet.

http://www.electrocompaniet.com/about/history.html

From the AES paper:

"INTRODUCTION: The lack of correlation between conventional amplifier distortion measurements and listening tests has been noted by many designers of audio equipment. Modem amplifiers often measuring under 0.01% total harmonic distortion at 1 kHz or below 0.1% intermodulation distortion, as measured with the SMPTE method, may sound completely unacceptable. It appears therefore that the audible difference between various amplifiers is not due to these static distortion figures alone, but some other reason must be involved. One possible reason is dynamic intermodulation distortion, which is created by the frequency rather than the amplitude characteristics of the signal. One form of dynamic intermodulation distortion is the transient intermodulation (TIM) which has been described in detail elsewhere [1]-[3]."

So, resistors can serve a useful purpose, low level distortion is audible, and amplifiers that measure "good" can and will often sound different from one another.

[mikebse2a3]

Mike do you mind sharing a little about the type cables you use???

Jay

Hey Jay

I will send you an e-mail so that I don't get Dean's thread to far off topic.

miketn

[Deang]

Capacitors:

I've lightened up on this quite a bit. I don't believe in magic, but I also don't believe it is yet possible to measure everything the ear/brain mechanism can pick up on. Please visit my business Facebook page and check out the testing Al did for me. He couldn't hear a difference using headphones, but his wife could. You know, if you think you're hearing a difference you probably are, and if you hear a difference that can't be accounted for through measurement, it very well may be placebo, but it doesn't change the fact that you're hearing a difference -- perception is everything -- it doesn't make it any less real, or does it?

When choosing what to use, I often think less about the sound than I do about quality of construction and materials. With metalized types, I look for products wound with thicker film, have good lead terminations, and use epoxy end caps to prevent moisture and oxygen from getting to the lead terminations. I had a conversation with Mark Blanchard of Klipsch a few years ago and he shared with me the tests that Klipsch had done with capacitors. Mark said performance differences were strongly tied to non-linear behavior under load and suggested I move to capacitors with higher Vdc ratings.

I'm not as wound up about this stuff as I used to be, but I think if the quality of construction and materials is there, good sound will follow.

I found the following quote in the archives. Does anyone want to venture a guess at who said it?

"...my intuition, for whatever that's worth, is that the ultimate culprit in capacitors sounding different is a "noise" issue, much more than a distortion issue. The distortions spoken of generally are a bit out of context with the associated distortions of the other components. I liken the effect of DA as like "walking on hot blacktop in sneakers" - where each step you take there is a "shloink" as you lift each foot off the tar. The cap has a type of "sticktion" during each transition. This would create noise unassociated with the signal."

[BEC]

"So, what do we gain with the swamping resistor? Less distortion."

Dean,

I don't go for long rambling posts. So let's just take one at a time. How do we have less distortion? 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.

[Deang]

I'm okay with a cable discussion -- heck, we already have everything else in here.

I still like the Kimber 4TC. I also like the tin coated Supra from Madisound.

[Deang]

"So, what do we gain with the swamping resistor? Less distortion."

Dean,

I don't go for long rambling posts. So let's just take one at a time. How do we have less distortion? 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.

Well, if you're not going to read anything while continuing to ask the same questions, I don't see much point in moving forward. 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?

[BEC]

Dean,

I did read that.

Let me sum that up. You said that Dennis said:

"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."

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?

[Deang]

It's okay Mark.

Bob, I know my limits. I quoted Dennis and I think I prefer that Dennis explain the comment and answer your question. I'm on the phone with him now -- he'll eventually get in here.

[Deang]

Bruce,

"Duder1982" is next, but I never received shipping info from him.

I just sent him an email, I should have the info soon.

[wallflower]

For what it's worth, Dean made a set of crossovers for me using PIO caps and all I'll say is they surpass anything else I've tried in my Klipsch Heritage speakers. They sound open, dynamic and natural, without a hint of being overly bright. Every other capacitor I've tried sounded way too sterile. Dean's crossovers cured that problem! Dean knows how to build outstanding crossovers.

IMHO, if you want great tube gear, Craig's the guy. If you want great crossovers Dean's the guy. They both know how to make Klipsch Heritage speakers sound great!

Cheers!

Jeff

[The Dude]

Bruce,

"Duder1982" is next, but I never received shipping info from him.

I just sent him an email, I should have the info soon.

I haven't seen the email, so I sent you via pm through the Klipsch forum. I all so messaged you on facebook just in case. Let me know if you didn't get it.

[NOSValves]

Jeff,

Thanks! I appreciate the mention.

[kaiser SET say]

Bruce,

"Duder1982" is next, but I never received shipping info from him.

I just sent him an email, I should have the info soon.

Dean, you have a pm coming from me as well and I meant Cornwall on the Bud's x-overs[] THX

[Deang]

Jeff exemplifies my thinking about this stuff. He heard the Roadshow Super AAs when Tom got them. We traded a lot of email. On the phone, Jeff said he really liked the way they made Tom's LaScalas sound, but that they didn't really sound like Heritage anymore, and that he didn't know if he wanted to give that up. So as a builder, what should I do with that? Some people really want to like the Heritage sound but can't make the adjustment - most of these people end up selling them. Al and myself have kept more than a few of these loudspeakers in the home with these networks. Jeff is hardcore Heritage - and what seemed like an easy choice to me, Jeff actually wrestled over for weeks. Anyways, thanks for the nice words Jeff and I'm glad you're enjoying those. So, what do you think about the idea that the only thing a paper in oil capacitor is good for is removing the highs?