Charge Coupled Crossover

[Epplerd]

Having seen that many contributors to the forum value the use of a charged couple crossover network. I wondered if there are any measurements to back up these assertions? Maybe I haven't searched hard enough, but I can't find any science on this site to explain it? With many members having the technical knowledge and possibly the necessary measuring equipment, would it be possible to conduct a null test to determine if there is any measurable difference between the audio passing through a single capacitor,( Xuf ) and two connected in series, (2Xuf) with an electrical charge applied to the junction?

[Robh3606]

Here we go again! Just try it.

http://www.audioheritage.org/vbullet...sed-Capacitors

Rob

[Epplerd]

Here we go again! Just try it.

http://www.audioheritage.org/vbullet...sed-Capacitors

Rob

Re: Here we go again, maybe it should be hear we go again?

The addition of IM (intermodulation) distortion is mentioned in a post on charge coupled crossovers, but no figures are quoted. If that's correct, if it was an audible amount it would likely be an objectionable addition to the sound. Unlike harmonic distortion IM distortion (sum and difference) isn't harmonically related to the original sound.



A null test would but this to bed. If there is a difference even -100db down it would be measurable. Surely a challenge worth taking up by someone with the appropriate test gear?


The final sound balance of a speaker system is a subjective assessment. But individual components can be measured. I believe this forum is populated by those who believe, where appropriate measurements are important.

[Robh3606]

Re: Here we go again, maybe it should be hear we go again?

The final sound balance of a speaker system is a subjective assessment. But individual components can be measured. I believe this forum is populated by those who believe, where appropriate measurements are important. It's a respected source of information, but is it possible on this topic there a sniff of snake oil starting to permeate the air?

We have been seeing posts like this for years. You seem to be the one looking for data so go do your null test. And when you get your results you can explain what they mean. Personally I couldn't be bothered. It takes 2 caps a resistor and a battery to try it in a simple second order network.

As to if you consider it snake oil I could care less what you or anyone else thinks. We can all make up our own minds and are free express our opinions.

You want to argue with somebody about go look up Greg.

Rob

[Epplerd]

We have been seeing posts like this for years. You seem to be the one looking for data so go do your null test. And when you get your results you can explain what they mean. Personally I couldn't be bothered. It takes 2 caps a resistor and a battery to try it in a simple second order network.

As to if you consider it snake oil I could care less what you or anyone else thinks. We can all make up our own minds and are free express our opinions.

You want to argue with somebody about go look up Greg.

Rob

I'm surprised that any attempt to measure this phenomena has caused such anguish. " You want to argue with somebody about go look up Greg". I believe that measuring outcomes in any sphere is a solid and reliable way of gaining knowledge. Opinion is one thing, facts are another. Best let's call it a day and throw some cold water or a cold beer on this topic.

[Robh3606]

I second the beer! This gets old constantly going over the same ground. I don't have an issue with measurements at all considering I couldn't do DIY builds without them.

The issue I have is why someone expects other to do the measurements and the work for them.

How about A trying it or B trying to measuring it.

The operative words are DIY if you have a technical issue with using CC networks.

Rob

[Mr. Widget]

I respect measurements as much as the next guy and have spent thousands of dollars purchasing several platforms and calibrated microphones, but I also know that so much of the subtlety that we perceive we are not yet able to quantify or measure. I do not know for a fact that charge coupled crossovers cannot be quantitatively shown to be superior to others, but I suspect that is the case.

The fact that Greg Timbers has used this topology in all of his better designs in recent years is pretty strong evidence that there is an audible improvement to this technique. That said, in my own designs I have opted for using more expensive capacitors and sticking with a traditional typology. It is not that I do not believe in charge coupling, I have just stayed with what I know will work.


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[Ian Mackenzie]

Having seen that many contributors to the forum value the use of a charged couple crossover network. I wondered if there are any measurements to back up these assertions? Maybe I haven't searched hard enough, but I can't find any science on this site to explain it? With many members having the technical knowledge and possibly the necessary measuring equipment, would it be possible to conduct a null test to determine if there is any measurable difference between the audio passing through a single capacitor,( Xuf ) and two connected in series, (2Xuf) with an electrical charge applied to the junction?

I have read your post. Sometimes it’s about picking your battles.

Firstly, let’s look at you and your motives for posting?

Taking a big picture view Greg Timber’s or JBL don’t have to prove anything. They spend considerably more on this style of network and have done for years.

I can tell you right now Greg does not give a rats arse what you think🤔.

The only people that matter are those that buy the product. They always have been and always will be. Numerous customers have reported a change in the sound quality near the end of the battery life used to bias the capacitors.

Without spending too much time on this thread your up to stirring the pot. Yes you. Too much time in lockdown Ah. If you don’t agree just say you don’t agree and move on.
Stop the “l need you to prove it crap” or get out of Dodge. The LHS forum is about preserving and living the long and successful JBL heritage. Not being a detractor.

The entire hifi industry has far more snake oil offerings where your approach would be well received.

We invite you to contribute what knowledge and positive experiences you have with jbl loudspeakers.

[SaturationPt]

I do not see the harm in the OP.

Here on LH as well on other forums where the same posters reside, we have no problem with changing Greg's designs. Simple changes from one type of capacitor or inductor to another, removing mass rings and changing port configurations and calling it an improvement without measurement to back it up. But in this case Greg did everything right? Seems inconsistent.

I too wonder about using only 9V as the swings will quickly exceed the 18V peak-to-peak that the 9VDC offset will affect, but as it has been described "a class A/B" solution. I guess you need to draw the line at what is commercially viable when you're sticking a battery in the back of a high-quality speaker system and 100VDC isn't practical. Is it possible that Greg saw other solutions but this was the cheaper one and therefore something that management at JBL would accept? Again those who claim all of the EL caps in crossovers are because "bean counters" made such decisions and Greg couldn't, ... inconsistent opinions here.

Greg made many changes and improvements over his career. Greg also wasn't afraid of abandoning one of his own designs for a better one, nor of questioning whether a design really was the best given current and improved knowledge and I feel that we should be willing to do the same. Pointing to Greg as the designer and saying that the OP shouldn't question the design just doesn't make sense to me, and I hope that there is a better answer.

[Robh3606]

Pointing to Greg as the designer and saying that the OP shouldn't question the design just doesn't make sense to me, and I hope that there is a better answer.

Yes there is. Open your wallet, pull out a $20 bill and give it a shot.

Rob

[Ian Mackenzie]

Hi Jeff,

I found your post interesting but misses the point.

No one has mentioned anything about design variations. That’s not the issue.

You refer to questioning of the design. Frankly that is not what l read from the poster. The reference was that is was subjective and it needed to be proven with measurements.

I viewed the posters history and he is certainly astute and smart enough to figure out the reason for the biased capacitors but he chose to raise doubt.

“Having seen that many contributors to the forum value the use of a charged couple crossover network. I wondered if there are any measurements to back up these assertions? Maybe I haven't searched hard enough, but I can't find any science on this site to explain it?”

Assertions? Baiting.

Dc biasing of capacitors is common practice in electronic circuits in particular audio electronics.
If you don’t understand it or don’t know about it then then in my book a technical explanation is not going to help your cause. It’s a bit like say oh l can hear this amplifier but l need to see measurements to prove that it goes. The consumer listens and if he likes it he buys it.

There is explanation in the library and elsewhere on the charge coupled crossover.

He then proceeded to rate the subjectivity of this product benefit.
This kind of language speaks of ignorance from a poster with a very low posting history.

The simple fact is in the case of the Solen 250 volt fast caps is used in JBL project SOA systems the impact of charge coupled approach blatantly obvious. There’s nothing subjective about it.

As for Greg he likes being quoted for the record.

[SaturationPt]

LOL

Okay, clearly I missed the point, and the intent of the OP as I don't know the posting history. I apologize.

[1audiohack]

I also read the OP’s post history. I see no history of baiting.

I think about the parts of audio that still are unquantified and often wonder if I or anyone I know has the equipment and intellect to make any headway on this front.

I understand being weary of the “same old questions” but if we knew of any genuine evidence, we could answer it and be done. No?

I don’t understand why so many bristle at a question that has not, or can not yet be answered. Seriously is it just because there is no evidence?

One thing is certain, the “Get off my lawn!!” answers are less than helpful. Unless running the last 12 people off this site is the goal.

Barry.

[JeffW]

Ed Meitner passed the idea on to Greg and Greg incorporated the idea into his statement systems. This is one of two topics that should have stayed in the private forums due to it causing unnecessary fretting and confusion.

It wasn't, evidently, a Greg Timbers discovery but something passed onto him by Ed Meitner, who was not as far as I can tell, a JBL employee. It's entirely possible GT never measured the effect, just relied on his ears to tell him it worked or not.

He mentions as much

"You can take this opinion for what it has cost you. I have been very pleased with biasing for many years. I use it in all applications that involve a capacitor and I have rarely been disappointed. Results may vary so if it doesn't do it for you that is okay too. "

Maybe Mr. Meitner has the scientific measurements behind the process, seems like he's the one who came up with it.

[Mr. Widget]

I also read the OP’s post history. I see no history of baiting.

I didn't bother to research the OP and see no reason to.

I read the post as a valid and sincere question.

I don’t understand why so many bristle at a question that has not, or can not yet be answered. Seriously is it just because there is no evidence?

Isn't that the foundation of religious faith?


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