Jbl 4367

[DaveC]

Since I've been told I don't anything about electricity, I've made an effort to learn about capacitor distortion in crossover networks. Believe it or not, there are AES papers on this topic. Here is a good starting place for those who wish to learn more:
http://www.aes.org/e-lib/browse.cfm?elib=14630

The title of the paper is nonlinear distortions in capacitors. The paper breaks down an extreme scenario where a capacitor used for a high pass filter can exhibit distortion. The things I learned from this paper are:
1. One would need to know the resonant frequency for the capacitor. Without this information, it's impossible to know whether a cap can be made better with a replacement.
2. One also needs to know the amount of signal current needed to make the capacitor distort.

The example used for this paper was a very extreme scenario so I wouldn't assume it relevant for any particular loudspeaker design.

As has been pointed out before, these crossver networks are DC biased. All you parts jockeys should also know that these drivers are very efficient. Therefore, very little current ever passes through the high pass filter, even under extreme scenarios.

Unlike the parts jockeys, I don't have all the answers. But I do know one should have a better understanding of how a speaker system works and be in a position to take distortion measurements before and after to know whether a capacitor change will have any positive effect on the loudspeaker's output signal.

"parts jockeys" who know all the answers? Dallas descends into more condescending, insulting speech when confronted with information he can't understand. A Lawyer who can't debate without Ad Hominem? Seriously? Actually, seriously pathetic. You should be embarrassed for yourself and all of WBF to be posting **** like this. It makes reasonable discussion impossible and you know this very well I'm sure. You're simply an embarrassment to reasonable, thinking people everywhere.

 

[sbo6]

not the case. the brand of x-over component was not chosen for this reason..dic has used bennic for years (at B&W too) and is happy with their performance vs audiophile caps and resistors i believe.

every one knows if you want to make speakers that sound good you have to have them blessed by god and sacrifice a goat on a bimonthly basis.. luckily both JBL and Vivid do this so michael wont have to do take any retrospective action... put the knife down michael, free the goat from the back yard.. its ok! the blessing was preformed at the factory.

I'd make a slight correction - dic has used bennic for years (at B&W too) and is happy with their PRICE/performance vs audiophile caps and resistors i believe.

@DallasJ - I understand your trepidation to change parts but it seems you are far from the "leave it alone and press play" kind of guy hence all the suggestions to upgrade the xover. Yes, replacement parts need to meet spec/design requirements but at the end of the day if JBL could've purchased the same mfr.s' RLCs but higher quality versions for the same $ they'd jump at it (starting with the cement blocks). Here's an example of an xover upgrade from a reputable "Parts jockey": http://www.evolutionacoustics.com/loudspeakers/mmtwoexact/

 

[RBFC]

Gentlemen, may we please refrain from personal attacks? Examine the content of the post and leave the personal aspects out of the discussion. This is Michael's sub-forum and I ask that we all respect this.

Lee

Michael, I believe you already mentioned that you've ordered new speaker stands. Do you feel that any of the performance issues under question will be improved by the addition of better stands (height, vibration control, etc)?

Lee

 

[treitz3]

Hello and good morning to you gentlemen. Personal comments are not welcome here at the WBF. As always, please refrain from making any while you post. Any more personal comments will be deleted and possible administrative actions could follow as well. We are all better than this. Here we have a topic that has many visitors as well as members looking on, the goal of the WBF is to have a friendly and cordial atmosphere. We will achieve our goal.

Let's talk about the technical merits of the posts without any personal commentary. This is how we learn and share ideas in this great hobby of ours. Thank you in advance for your cooperation.

Tom

 

[dallasjustice]

First of all, I never asked anyone for advice on swapping out crossovers. This is just the way this forum works. Someone posts about a real experience and then all the armchair experts proceed to offer unsolicited "expert" advice.

I don't mind the unsolicited advice as I'm willing to challenge the so called expert advice.

Anyone capable of recognizing basic social cues would have recognized many pages ago that I'd never swap out the parts in my speakers. Yet the experts carry on with their unsolicited recommendations. It's hilarious.

Magico probably uses the most expensive parts in their crossver networks. As I've posted elsewhere, the Magico speakers don't measure even close to as well as speakers like vivid and JBL 4367.

I'd make a slight correction - dic has used bennic for years (at B&W too) and is happy with their PRICE/performance vs audiophile caps and resistors i believe.

@DallasJ - I understand your trepidation to change parts but it seems you are far from the "leave it alone and press play" kind of guy hence all the suggestions to upgrade the xover. Yes, replacement parts need to meet spec/design requirements but at the end of the day if JBL could've purchased the same mfr.s' RLCs but higher quality versions for the same $ they'd jump at it (starting with the cement blocks). Here's an example of an xover upgrade from a reputable "Parts jockey": http://www.evolutionacoustics.com/loudspeakers/mmtwoexact/

 

[FrantzM]

Hi

Humble EE but mostly into IT integration.. Parts are not my expertise...

A few things I know, they are proven facts:

• We human audiophiles, are able to sincerely hear differences where there are NONE.
• We human audiophiles can focus on areas of audio reproduction and mistake this for new perceptions.
• Parts can be indeed different in performance. How much is audible or perceptible is the debate at hand. One more grain of salt for sure change the salinity of a water solution .. Can the human taste apparatus perceive it? I doubt it

Based on that, I need to see proofs of the so-called "better" especially the always brutally-expensive parts from Mundrof, for example, before I would change anything in a design. Of course, I know the designer to be a fallible human being and her/his design can be perfected but by whom? Me? I could overshoot Steph Curry on a fluke day but .. what are the odds? So before I delve into changing parts and proclaiming the system sounds better, I would like to see proofs... objective proofs that things have changed and for the better.
I am interested enough in the 4367 to take a trip to listen to it... I am thinking about serious horns or better high sensitivity controlled or constant distortion speaker systems, now, well-designed speaker system that will provide many years of musical enjoyment. Tweaking ad infinitum while a joy in itself is a detriment to music enjoyment. Some are lucky enough to enjoy highest caliber Live Music, most can't.. The logistics are simply impossible for any human. We invented audio reproduction for this very reason and its potential is infinite. I'd rather enjoy it.

 

[Folsom]

Since I've been told I don't anything about electricity, I've made an effort to learn about capacitor distortion in crossover networks. Believe it or not, there are AES papers on this topic. Here is a good starting place for those who wish to learn more:
http://www.aes.org/e-lib/browse.cfm?elib=14630

The title of the paper is nonlinear distortions in capacitors. The paper breaks down an extreme scenario where a capacitor used for a high pass filter can exhibit distortion. The things I learned from this paper are:
1. One would need to know the resonant frequency for the capacitor. Without this information, it's impossible to know whether a cap can be made better with a replacement.
2. One also needs to know the amount of signal current needed to make the capacitor distort.

The example used for this paper was a very extreme scenario so I wouldn't assume it relevant for any particular loudspeaker design.

As has been pointed out before, these crossver networks are DC biased. All you parts jockeys should also know that these drivers are very efficient. Therefore, very little current ever passes through the high pass filter, even under extreme scenarios.

Capacitor resonate frequency is essentially based on it's value in farad when it comes to film capacitors. Which makes them freely swappable. However in the recent pic with the two electrolytic capacitors concerns come up with high values and inductors, for potential resonation problems. Large capacitance can resonate with inductors; how "stiff" the capacitor is, the "loss factor" are big determiners of this, which is in relation to resonate frequency. So knowing that in order to swap those out one would have to check if the originals are lossy, because the replacements may need to be (and there may not be a replacement that would work).

It's pretty much impossible to exhaust film caps based on current (10kw amp maybe?). However for example with those 100v capacitors, were you to apply a big enough amp with enough voltage you could toast them. The ones in the crossover are rated lower than probably any replacement considerations.

The physical factor to capacitors shows how Teflon can be superior, given how they're huge!

Thank you for reading up on the subject in some way. I wish more people on forums weren't afraid to just read a bit on the subjects they want to talk about. It's not a small effort, but it's very beneficial for community so it's greatly appreciated (by me at least).

 

[sbo6]

Hello and good morning to you gentlemen. Personal comments are not welcome here at the WBF. As always, please refrain from making any while you post. Any more personal comments will be deleted and possible administrative actions could follow as well. We are all better than this. Here we have a topic that has many visitors as well as members looking on, the goal of the WBF is to have a friendly and cordial atmosphere. We will achieve our goal.

Let's talk about the technical merits of the posts without any personal commentary. This is how we learn and share ideas in this great hobby of ours. Thank you in advance for your cooperation.

Tom

Look no further than the OP...

I find it comical that the OP, in a thread that primarily focuses on specs, charts, graphs and DSP is insulted and gets defensive when suggestions to modify the internal xover are offered. How about a "thank you", the same that's offered to any of his WBF buds. Message well received.

I'll add 1 more tidbit as a "part jockey" and ex-amateur musician/studio guy - Studio monitors in general don't focus on the best of the best internal components or cabinet damping material, they primarily focus on their customers' needs - cabinet and driver durability and portability in a working environment. These are the facts. Pop open a pair of Yamaha, Alesis or yes, JBL studio monitors and you'll see the same cheapo components which adversely affect the sound quality.

 

[treitz3]

Hello again gentlemen. 3 posts have been deleted because once again, personal comments were made with zero technical aspect challenged or commented upon. The management team knows exactly who the offenders are and I will state this very clearly as I want you to consider this an official warning - If one more personal comment is made in this thread by those members for any reason, you will be enjoying an involuntary 3 day vacation courtesy of the WBF. This is not up for debate.

To sb06, I went back and took a look at the original post and find nothing wrong with it. The message you received is not the message sent. The "personal commentary will stop" is the message. I can appreciate the suggestions and commentary on modifying the crossover as I have been working on a 12K+ external crossover upgrade for my speakers......for the same reasons you mentioned.

With that said, let's all please get back on topic without the personal insults.

Tom

 

[Robh3606]

FWIW you guys are completely missing the boat on a couple of things. First off you are assuming that the engineering group at JBL is ignoring the boutique capacitors. Well you are incorrect. With the capacitors being DC biased they don't see a benefit to cost ratio worth the cost of $200 each for some of the values. The whole reason that they do the Charge Coupled networks is the improve the sound quality. To do that you double both the value and the part quantity so it is not inexpensive to do so. I build all my networks using the Charge Coupled topology because it really does work. You can hear a difference. As far as the electrolytic's they were specifically chosen and will in no way degrade the sound. We have had that conversation more than once over at Lansing Heritage.

http://www.audioheritage.org/vbulletin/showthread.php?3555-Bypassed-and-Biased-Capacitors

Rob

 

[sbo6]

Hello again gentlemen. 3 posts have been deleted because once again, personal comments were made with zero technical aspect challenged or commented upon. The management team knows exactly who the offenders are and I will state this very clearly as I want you to consider this an official warning - If one more personal comment is made in this thread by those members for any reason, you will be enjoying an involuntary 3 day vacation courtesy of the WBF. This is not up for debate.

To sb06, I went back and took a look at the original post and find nothing wrong with it. The message you received is not the message sent. The "personal commentary will stop" is the message. I can appreciate the suggestions and commentary on modifying the crossover as I have been working on a 12K+ external crossover upgrade for my speakers......for the same reasons you mentioned.

With that said, let's all please get back on topic without the personal insults.

Tom

To the gents in charge - by OP I meant Original Poster, not the Original Post. The post is noble, the resultant exchanges are questionable.

No more posts about xover upgrades from the EE "armchair experts", we will leave this debate and expertise up to the lawyers...

 

[Folsom]

FWIW you guys are completely missing the boat on a couple of things. First off you are assuming that the engineering group at JBL is ignoring the boutique capacitors. Well you are incorrect. With the capacitors being DC biased they don't see a benefit to cost ratio worth the cost of $200 each for some of the values. The whole reason that they do the Charge Coupled networks is the improve the sound quality. To do that you double both the value and the part quantity so it is not inexpensive to do so. I build all my networks using the Charge Coupled topology because it really does work. You can hear a difference. As far as the electrolytic's they were specifically chosen and will in no way degrade the sound. We have had that conversation more than once over at Lansing Heritage.

http://www.audioheritage.org/vbulletin/showthread.php?3555-Bypassed-and-Biased-Capacitors

Rob

DC biasing doesn't stop the benefits of capacitor differences. It reduces microphonics, but doesn't eliminate sonic signature. So, no, no one's incorrect on that. We know Harmon is choosing what they think is the best performance to price ratio for their goals. The boat is not missed. No one thinks Harmon simply doesn't know about different capacitors.

Cost? They probably don't pay over $2 a cap, if even over $1.

This really has nothing to do with differences in capacitors being used. Also it's the What's Best Forum, so of course we'll discuss stuff with diminishing returns!

Do you use diodes to rectify for your DC biasing, like Harmon? It seems most people just do 9v batteries. Either way it's pretty cool.

 

[fas42]

In the really cheap speakers I have played with over the years the very first thing I do is dive inside and eliminate all the obvious weaknesses in the construction of the unit - things like "rubbishy" capacitors and less than ideal connections. Immediately it stops sounding like a "cheap speaker", becomes remarkably more 'musical' - technically and measurement wise very little has altered, but the audible artifacts from poor quality aspects of the assembly that can be easily resolved have been eliminated - sometimes, this is enough to make the listening experience progress from unpleasant, to something worth putting more time into.

This is just to say that an audio component that is capable of very high performance, such as a premium speaker, should have everything reasonable done to extract its full potential.

 

[dallasjustice]

ABX tests on capacitors

Here is another paper. This time we have real supposed science from Duncan and Dodds in conjunction with KEF and B&W and a cap manufacturer.
http://www.aes.org/e-lib/browse.cfm?elib=14444

I'd rather not continue on with the great crossover/capacitor debate on this thread. The following is a breakdown of Duncan & Dodds findings for those of you who don't subscribe to the AES library.
http://www.audiosciencereview.com/f...-digest-audio-capacitors-myth-or-reality.176/

 

[DaveC]

In the really cheap speakers I have played with over the years the very first thing I do is dive inside and eliminate all the obvious weaknesses in the construction of the unit - things like "rubbishy" capacitors and less than ideal connections. Immediately it stops sounding like a "cheap speaker", becomes remarkably more 'musical' - technically and measurement wise very little has altered, but the audible artifacts from poor quality aspects of the assembly that can be easily resolved have been eliminated - sometimes, this is enough to make the listening experience progress from unpleasant, to something worth putting more time into.

This is just to say that an audio component that is capable of very high performance, such as a premium speaker, should have everything reasonable done to extract its full potential.

I agree. Just replacing the push connectors with a soldered connection and upgrading wiring is easily audible let alone upgrading xo parts. Furutech also makes pure copper push connectors, FT-210 I believe, they are really good...

Here is another paper.

Some capacitors sound a lot alike, some are very different. I have no idea exactly what was done in the test, "fancy film capacitor" means nothing to me, but apparently is a cover-all in Amir's eyes for a huge range of different types of capacitors. Caps can use different metals foils and dielectrics, different kinds of metalized films, etc... There's issues with the test imo, if the "fancy film capacitor" was a Jupiter copper foil cap, and the other cap was the crappy metalized film cap in your speakers I have no doubt a significant difference would be noticed. There's also the fact that "Electrolytic capacitor was picked by 14 out of 14 testers/test to sound duller. And 13 out of 14 to have worse spatial information." I can't make out the thumbnails and don't want to register right now either.

With the amount of time you've put into researching the topic you could have figured out what caps were what and ordered a couple of copper film caps to try out, so you can see for yourself. Why people like you never want to experiment for themselves is a great mystery to me.

 

[Folsom]

I'd rather not continue on with the great crossover/capacitor debate on this thread./[/url]

Well, what's next on the list? Dedicated stands?

 

[dallasjustice]

Well, what's next on the list? Dedicated stands?

As Lee recalled, I had custom isoacoustics stands built for the 4367. I really didn't really want to talk about it. I have the stand and they are okay. I think Dave from isoacoustics is a good guy. He followed through and made certain I finally got what I wanted even though there were numerous production/parts mishaps. Overall they are a good product. One thing I noticed which is probably not fixable is that one side of the stand is not perfectly flat. The other side is flat. I have carpet so the slightly mishappen side sits on the carpet and the flat side fits nicely to the underside of the JBLs. I'm sure it doesn't affect performance. But if I had a hardwood floor, I'd have a problem.

I cross my speakers over with a 2nd order NT filter at 80hz. So the JBLs aren't really doing much at really low frequencies. The stands look nice. But I can't make any crazy claims about how they make the system sound better. If there's any difference, it's very subtle. I wouldn't recommend isoacoustics unless one wanted something that looks nice and unobtrusive.

 

[microstrip]

FWIW you guys are completely missing the boat on a couple of things. First off you are assuming that the engineering group at JBL is ignoring the boutique capacitors. Well you are incorrect. With the capacitors being DC biased they don't see a benefit to cost ratio worth the cost of $200 each for some of the values. The whole reason that they do the Charge Coupled networks is the improve the sound quality. To do that you double both the value and the part quantity so it is not inexpensive to do so. I build all my networks using the Charge Coupled topology because it really does work. You can hear a difference. As far as the electrolytic's they were specifically chosen and will in no way degrade the sound. We have had that conversation more than once over at Lansing Heritage.

http://www.audioheritage.org/vbulletin/showthread.php?3555-Bypassed-and-Biased-Capacitors

Rob

Rob,

I have pointed this aspect several times about the top JBL's crossovers. Accepting what you are calling "Charge Coupled topology" - a fancy name to DC biased capacitor opens the Pandora box, as it suggests that it changes the way the capacitor sounds and all the "magic" around it. If DC bias has a real effect we must accept that burn-in, fancy dielectrics and metals all have some "raison d'être". Just FIY, I prefer the Mundorf's in my Soundlab's because they are easily available and sounded better than the originals. Although each speaker uses only one capacitor, unfortunately it is a relatively high value, otherwise I would have already tried the DC bias technique. But it is in my wish list, thanks for remembering me!

 

[Robh3606]

Hello Micro

I don’t think it open pandora’s box at all. I am no stranger to burn in but what are we talking about burn in for electronics of mechanical break in like a loudspeaker. The effects of burn in on electrical components is well understood. There are easilly measureable differences. If you look at the part screening specifications for these parts used for space and military applications there are even delta requirements for selected parameters that if you exceed them the parts cannot be used. There are always shifts but that does not mean they would be audible if used in say an amplifier as an example.

Now with speakers 500 hours of burn/break in?? The only you are breaking in is your mind IMHO. With materials you have beryllium, aluminum, magnesium and titanium used in compression drivers. They are all different in their properties. I like beryllium best. I don’t see it as pandora’s box. Under certain circumstances and uses there will be audible differences but not in all. That is where I make the distinction.

Hello Folsom

I use the older battery method.

Rob

 

[FrantzM]

Not sure that I accept "anything".. I need to be proven somehow of the ways capacitor A is better than cap B...