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Crossover Capacitors and Crossovers In General


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17 minutes ago, Crankysoldermeister said:

There you are. I was starting to worry a little.

 

Getting new carpet installed today.  You don't realize how much crap you have until you have to move it out of the way 😥

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2 minutes ago, mboxler said:

 

Getting new carpet installed today.  You don't realize how much crap you have until you have to move it out of the way 😥

My biggest fear at the moment. The law of "accumulation" is biting me at the ankles now and moving up.

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18 hours ago, Crankysoldermeister said:

There is actually a ton of data on capacitors, it's just that nobody understands it, lol.

NoBody means most people. But some do understand it to various degrees based on requirements beyond Audio frequencies. 

 

When I worked as project manager for a Reverse Engineering/Repair company (upgrading control electronics for GE Wind Generators among other things) a co-worker/engineer proved to me that Non-polar Film type AXIAL leaded capacitors had assymetrical behavior under certain conditions at high frequencies  I can't recall.

 

I call it the "inny vs. the outy." One lead connects to the innermost portion, while the other lead connects to the outermost portion of the "toilet paper roll" for lack of a better term. This is why I sometimes use two capacitors at half the intended value in parallel with the letters on the caps facing opposite directions. It also allows for the purchase of 10 parts at a lower price, which you may not need until later, but the discount allows you to accumulate extra parts, over time, that are "effectively" free for future projects, or tweaking.

 

Example on a first order tweeter rolloff:

You can make a 4 uF capacitor with Two 2 uF caps in parallel with the labels going opposite directions (probably not that important at Audio frequencies, but why not?). Or you can use a single 2 uF if the tweeter is too hot a lower frequencies. So what if, after listening, you think 3 uF would be perfect. You can use a third 2 uF in SERIES with the second 2 uF capacitor to make a 1 uF with a higher voltage rating (not relevant for crossovers but ESR is). Since capacitors in parallel ADD their values, you would have 3 capacitors total. The two in series that make the 1 uF would then be in parallel with the 2 uF, thus creating a 3 uF as seen by the amplifier and tweeter.

 

When PWK was using K-55's and K-77's for all the Heritage speakers with different Bass sections, he was able to buy at higher volume to lower the price, just like in Automotive Electronics!

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32 minutes ago, ClaudeJ1 said:

NoBody means most people. But some do understand it to various degrees based on requirements beyond Audio frequencies. 

 

 

Although I don't consider myself part of the "understanding" group, here's my take on capacitors.  I'll focus on the 2uf value since that's the value of choice in the Heritage tweeter circuit.

 

I bought some 2uf polyester caps off the Bay to play with.  

 

I feel that ESR isn't important at audio frequencies, and because the dissipation factor of all dielectrics changes with frequency, ESR actually decreases as frequency increases.  Here are my measurements of these caps...

 

1000hz, reactive impedance 80 ohms, ESR .37 ohms.  

10000hz reactive impedance 8 ohms, ESR .07 ohms.

 

In either case, the reactive impedance overwhelms the ESR, making it irrelevant???

 

Again, I'm no EE, so please correct me if I'm wrong.

 

Mike

 

 

 

 

 

 

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im late to the party, glanced over the thread at 3 or 4 pages long & saw some well written logical comments... apparently some have been deleted.  :(  

 

some comments on this thread, a couple phone calls & the many PMs ive received have mostly answered the capacitor questions i was asking recently.  the members here that take the time to reply to what some may consider stupid questions are very appreciated... we all were beginners at some point & relied on those that knew more than we do.    

 

this type of info is very constructive & helpful to me & other forum members that are just trying to learn more.  there was never a issue with the service being provided for klipsch crossovers,  most are just looking for some basic details on what this all means for what we will actually hear to make an educated decision. 

 

thanks again to those that take/took the time to help out with non biased data & explanations. 

 

 

 

 

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7 minutes ago, 001 said:

im late to the party, glanced over the thread at 3 or 4 pages long & saw some well written logical comments...

 

thanks to those that take/took the time to help out with non biased data & explanations. 

 

 

 

that's the thing then isn't it...

 

Simply studying something fundamentally changes that thing... inserting a bias.

 

runs away

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16 hours ago, Crankysoldermeister said:

Al used to tell me they were perfect for SET amps because of their benign impedance. I’m like, “Al, they’ve only got 3 watts and now they only have 1.” I honestly still don’t know who was right. 

 

What he means is the output impedance from most SET amps is high due to them not using any negative feedback from the output to lower it. Since the output impedance is so high with any variation in load impedance you get large voltage differences. An amplitude vs frequency plot shows this well and isn't a straight line. The amp behaves more like a constant current source than the ideal voltage source.

 

With a voltage source the voltage stays relatively the same and current though the load changes. With a current source the current through the varying load stays relative the same but voltage changes.

 

He is saying his networks are flat for impedance vs frequency.

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3 hours ago, ClaudeJ1 said:

I call it the "inny vs. the outy." One lead connects to the innermost portion, while the other lead connects to the outermost portion of the "toilet paper roll" for lack of a better term. This is why I sometimes use two capacitors at half the intended value in parallel with the letters on the caps facing opposite directions. It also allows for the purchase of 10 parts at a lower price, which you may not need until later, but the discount allows you to accumulate extra parts, over time, that are "effectively" free for future projects, or tweaking.

 

Exactly why I say construction can have an impact on the variables. The rolled types still are made but for the competitive capacitor manufacturers for high frequency, fast rise time switched currents they have been stacking the layers in different manners and instead of having one lead at the inner foil roll and the other at the outside foil roll they offset each plate to one side of the package and the extended part of the plate is connected to the lead, this give much more uniform characteristics.

 

Here is an image.

capconstruction.png

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4 hours ago, mboxler said:

 

I, too, wonder at what point a measured difference is audible.

 

This would be the debated aspect even if we show different plots with different capacitors. At what point is something audible?

 

In the instance of balance/crossover networks I am not seeing distortion as going to be a huge influence, speaking about just capacitors since there isn't much of a signal across them. When I measure distortion or linearity in capacitors I have push a lot of voltage across them to show it, they are the  entire load not a very small portion of the load.

 

I'd wager it was what was alluded to by "voltage transfer", basically amplitude vs frequency of the filter networks. Even at 20kHz a 2uF cap is still 3.9 ohms differences in ESR aren't going to make a huge difference, there will be a difference but is it audible? If the tweeter is even 8 ohms at 20kHz;

 

With an ESR of say 1 ohm vs .01 ohm we get 67% and 62% respectively. So I suppose the higher ESR gets you'll reduce amplitude out. I would think 1 ohm at 20kHz is a pretty bleak ESR for a film cap so a good worst case scenario will lose 5% of the output at 20kHz.

 

How good is hearing up at 20kHz? Is it sensitive enough to notice 5% difference?

 

These are more the questions we will end up with after we get the measurements.

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28 minutes ago, Schu said:

that's the thing then isn't it...

 

Simply studying something fundamentally changes that thing... inserting a bias.

 

runs away

 

Reminds me of a meme:

 

 

i-used-to-think-then-i-tock-a-sounds-like-23910068d.jpg

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6 minutes ago, Curious_George said:

"Simply studying something fundamentally changes that thing... inserting a bias"

 

Simply studying something, fundamentally changes (AKA - the way you perceive it), that thing. Inserting bias. 

I agree. 

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28 minutes ago, Schu said:

 

 

that's the thing then isn't it...

 

Simply studying something fundamentally changes that thing... inserting a bias.

 

runs away

 

that may be true, but the facts & data are not biased...

 

i usually prefer a more straightforward approach to looking at facts & data, for the most part i am capable of setting aside any personal bias when presented with facts.  having an open mind allows one to learn new things.  

 

 

 

 

 

     

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5 minutes ago, 001 said:

 

that may be true, but the facts & data are not biased...

 

i usually prefer a more straightforward approach to looking at facts & data, for the most part i am capable of setting aside any personal bias when presented with facts.  having an open mind allows one to learn new things.  

 

 

 

 

 

     

 

“Contradictions do not exist. Whenever you think that you are facing a contradiction, check your premises. You will find that one of them is wrong.” ~ Ayn Rand

A premise is "facts and/or data". Not all data is accurate and not all facts are facts.

 

I know we are talking about capacitor data in this case and it is hard to dispute manufacturer data such this. But a blanket statement like "facts & data are not biased" is not necessarily accurate. 

 

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